User Experiences of Ball Blankets in Adults with Depression-Related Insomnia: A Qualitative Content Analysis Study

Abstract

Insomnia is prevalent in patients suffering from depression and may itself exacerbate the disability associated with depression and impede the path to recovery. Although crucial in ensuring meaningful interactions and interventions for patients, research on patients’ experiences of depression-related insomnia and its treatment is limited. The purpose of this study was therefore to investigate how adult patients with depression-related insomnia experience sleeping with a weighted Protac Ball Blanket®, focusing on how the blanket feels and works and contributes to their subjective sleep quality experience. An inductive content analysis approach was adopted. Semi-structured interviews were conducted with 13 patients. Four categories were identified: 1) Deep and dynamic touch pressure from the plastic balls induced calmness; 2) Changing sensory impressions from the rolling balls distracted attention from distressing thoughts and emotions; 3) The ball blanket improved the quality and quantity of sleep, which increased daily well-being; 4) Sleeping with the ball blanket was associated with positive as well as negative experiences depending on personal preferences for sensory stimulation. This study explains how the Protac Ball Blanket® as a potential non-pharmacological sleep-intervention improved the sleep of adult patients with depression-related insomnia. The blanket was found meaningful for coping with sleeplessness and with mental and physical unrest.

Introduction

Insomnia is a core symptom of depression (Baglioni et al., 2011; Riemann et al., 2001) and occurs in more than 90% of the 264 million people who suffer from depression worldwide (Franzen & Buysse, 2008; James et al., 2018; Park et al., 2013). Furthermore, insomnia is a major contributor to the disability associated with depression (Franzen & Buysse, 2008; Park et al., 2013; Riemann et al., 2001; Sunderajan et al., 2010) and is characterised by difficulty falling asleep and maintaining sleep and by early morning awakening, all causing poor sleep quality (Riemann et al. 2017; Riemann et al. 2020). Insomnia may lead to psychosomatic disorders, addiction, cardiovascular and metabolic diseases (Riemann et al., 2001; Sunderajan et al., 2010). It has economic, emotional and social consequences (Faulkner & Bee, 2016; Riemann, et al. 2017; Sunderajan et al., 2010), has a negative impact on depression recovery and is a serious risk factor of suicide (Faulkner & Bee, 2016; Littlewood et al., 2016; Sunderajan et al., 2010). Despite its high prevalence and burden, insomnia remains under-recognised and undertreated in patients with depression (Araújo et al. 2017; Faulkner & Bee, 2016; Sunderajan et al., 2010). This may be explained by the fact that insomnia is viewed as a by-product secondary to depression that will automatically resolve following pharmacological treatment of depression (Faulkner & Bee, 2016). Another explanation may be the sparse research into patients’ experience of depression-related insomnia and its treatment, which hampers meaningful interactions and interventions for patients (Araújo et al. 2017; Dyrberg et al., 2021; Faulkner & Bee, 2016; Kristiansen et al. 2023). Hence, future studies focusing on the subjective experiences of insomnia and its treatment in patients with depression are warranted (Faulkner & Bee, 2016). Pharmacological treatment of insomnia often includes prescription of benzodiazepines and z-drugs, but guidelines recommend these drugs only for short-term use as they often cause addiction or have side effects (Griffiths & Johnson, 2005). Psychological and behavioural approaches, such as cognitive behavioural therapy for insomnia (CBT-I), are guideline-recommended treatment approaches for insomnia Riemannet al. 2017). However, CBT-I requires patient participation during multiple treatment sessions focusing on cognitive therapy, stimulus control, sleep restriction therapy, sleep hygiene education, etc. This challenges patients’ adherence because they may suffer from daytime fatigue, which hampers their cognitive and emotional functioning (Dyrberg et al., 2021). Research underpins the efficacy of CBT-I, but achieving satisfactory results takes time (Hsu et al., 2015; Riemannet al. 2017). Hence, additional, simpler, non-pharmacological methods to promote or maintain better sleep are required. Such methods may also reduce patients’ need for benzodiazepines and z-drugs.

A weighted Protac Ball Blanket^® (PBB) is a potentially appropriate, easy-to-use and self-directed intervention aid for managing sleep problems in depression (Hvolby & Bilenberg, 2011; Kristiansen et al., 2020). Although sparse evidence exists for its use (Gimenno-Ruiz, 2020; Hvolby, 2020; Hvolby & Bilenberg, 2011), the blanket has been used occasionally since the early 1990s in Denmark as a tranquilising treatment option within psychiatry for patients with all sorts of diagnoses and sleep problems. However, patients’ values, preferences and experiences should be scientifically researched to build recommendations for PBB use as a health management strategy for sleep problems in depression.

The use of weighted blankets has been reported to produce beneficial calming, relaxing and anxiety-reducing effects on patients with either chronic insomnia, anxiety or attention deficit hyperactivity disorder (ADHD) (Ackerley et al., 2015; Eron et al., 2020; Larsson & Joensen 2015; Wallis et al., 2018). Furthermore, weighted blankets have been reported to reduce sleep onset latency and other sleep-related symptoms in children with ADHD and adults with affective diagnoses and ADHD with co-occurring insomnia (Ekholm et al., 2020; Hvolby, 2020; Hvolby & Bilenberg, 2011). One of these studies also reported that the daily level of functioning and quality of life increased in children with ADHD after eight weeks of weighted PBB use (Hvolby, 2020). One study found that sleep bout time increased during weighted chain blanket use in patients with chronic insomnia unrelated to a comorbid condition (Ackerley et al., 2015). The same study found that the patients liked sleeping with the weighted chain blanket, found it easier to settle down to sleep and reported a much better sleep quality, which made them feel more rested in the morning (Ackerley et al., 2015). The results of these studies indicate that weighted blankets may positively impact sleep in patients with depression-related insomnia. However, no qualitative studies have explored patients’ subjective experiences and preferences of sleeping with weighted blankets (Champagne et al., 2015), and little is known about the benefits and limitations of using weighted blankets in the treatment of depression-related insomnia. Therefore, the aim of the present study was to investigate how adult patients with depression-related insomnia experience sleeping with a Protac Ball Blanket^® PBB, focusing on how the blanket feels and works and contributes to their subjective sleep quality experience.

Materials and methods

We conducted semi-structured individual interviews and performed inductive content analysis to describe and explain how adult patients experienced sleeping with a PBB (Dey, 2005; Elo & Kyngäs, 2008; Elo et al., 2014; Erlingsson & Brysiewicz, 2017; Graneheim & Lundman, 2004; Lindgren et al., 2020; Schreier, 2012). The reporting of the study adheres to the consolidated criteria for reporting qualitative research (COREQ): a 32-item checklist for interviews (Tong et al., 2007).

Setting

The study was conducted in three outpatient clinics in Denmark: 1) The Outpatient Clinic for Mania and Depression at Aarhus University Hospital, Central Denmark Region; 2) The Mental Health Department Odense—University Clinic, Mental Health Service, Region of Southern Denmark; and 3) The Psychiatric Outpatient Clinic, Esbjerg, Region of Southern Denmark.

Participants

Thirteen patients (eight women and five men) aged 19-62 years (mean 32.9 years) were included in the study.

Inclusion criteria:

1. Male or female, aged ≥18 years with a first depressive episode or recurrent depressive disorders according to the International Classification of Diseases, tenth version (ICD-10) (F32-33) or (F32-33 in combination with anxiety disorders F40-41.2), where the current depressive episode duration is less than 2 years.

2. Patients who experienced poor sleep quality and had a Global Pittsburgh Sleep Quality Index (PSQI) score ≥5.

3. Patients who reported one or more of the following:

   • Sleep onset latency > 30 min, occurring ≥ 3 nights a week for ≥ 14 days.

   • Wake time after sleep onset > 30 min, occurring ≥ 3 nights a week for ≥ 14 days.

   • Early morning awakenings ≥ 3 nights a week for ≥ 14 days.

Early morning awakening was defined as the final morning awakening with a wake-up time ≥ 1 h prior to the desired wake-up time (Bech, 2005; Ikeda et al., 2017;. Riemann. et al. 2017).

Exclusion criteria:

• Depression, according to ICD-10 criteria, duration > 2 years.

• Hypersomnia (ICD-10: F51.13).

• Harmful use of or dependence on psychoactive drugs (ICD-10: F10-19).

• Patients with diseases directly affecting sleep quality (such as severe chronic pain issues, sleep apnoea, etc.).

• Circadian rhythm sleep-wake disorders (ICD-10; G47.20-47.26).

• Participation in other research interventions during the intervention period.

The patients recruited had concluded participation in a randomised crossover trial evaluating the efficacy of the 7 kg Protac Ball Blanket^®, Flexible—cotton 140x200cm filled with plastic balls, on total sleep time (Kristiansen et al., 2020). The PBB contains 5 cm balls, which are divided into compartments so that the balls can move and provide a dynamic sensory stimulation. In the trial, patients were allocated to a sequence, either “AB” or “BA”, each lasting 4 weeks. Patients randomised to the “AB” sequence received treatment A (Protac Ball Blanket^®) in the first 2 weeks and then switched to treatment B (treatment as usual) in the last 2 weeks; patients who were randomised to the BA sequence received the two treatments in the reverse order. Treatment as usual referred to patients’ self-owned duvet, which were all different variations of down quilts. Patients slept in their own home environments, and their sleep was monitored by actigraphy and a sleep diary. For further information, please see the research protocol (Kristiansen et al., 2020).

Purposeful sampling was used to recruit participants to ensure variation in content and multiplicity (Elo et al., 2014). Participants should represent: 1) both genders, 2) both sequences (AB and BA), 3) all three data collection sites and 4) have different ages. Furthermore, both patients with positive and negative experiences with the PBB were asked to participate. Full informed consent was obtained from all study participants before inclusion. None of the consulted patients refused to participate in the interviews.

The participants’ demographic information is presented in Table 1. All but two patients received anti-depressant treatment. Furthermore, all but two patients received either or both hypnotics and antipsychotic drugs to initiate sleep. In three cases, changes to the prescribed medicines were made during the trial (See Participant 1 + 7 + 9, Supplementary Table 1).

Table 1. Participant demographics.

Participant	Gender	Age	Diagnosis*	PSQI score** (baseline)	Randomisation sequence***	Length of interview (min)	Interview format****
1	F	26	F33.1	13	AB	46.35	P
2	F	24	F33.2	13	BA	40.29	P
3	F	25	F32.2	13	BA	44.04	P
4	M	26	F32.2	16	AB	53.68	P
5	F	29	F33.1	17	AB	60.00	P
6	M	24	F32.1	14	AB	27.57	P
7	F	24	F33.1	11	AB	40.54	P
8	F	22	F32.1	14	BA	43.20	P
9	F	19	F32.1	16	BA	40.40	P
10	M	50	F33.1	12	BA	52.19	Z
11	M	56	F33.2	14	BA	41.48	Z
12	F	41	F33.1	17	AB	38.03	Z
13	M	62	F33.1	18	BA	43.13	Z

* F32.1 Moderate depressive episode, F32.2 Severe depressive episode without psychotic symptoms, F33.1 Recurrent depressive episode moderate, F33.2 Recurrent depressive disorder, current episode severe without psychotic symptoms.

** PSQI (Pittsburgh Sleep Quality Index Score) when screened for eligibility.

*** AB (A = Intervention Protac Ball Blanket^®, B = Treatment as usual), BA (B = Treatment as usual, A = Intervention Protac Ball Blanket^®).

**** P = psychical meeting, Z = Zoom online meeting.

Data collection

Data were collected using individual semi-structured interviews (Dicicco-Bloom & Crabtree, 2006; Kvale, 2007). Nine interviews were held in the outpatient clinics and four as online meetings due to a large geographical spread. The interviews lasted approx. 30–60 min (mean 43.92 min). The interviews were conducted by STK from Nov 2020 to Feb 2022. Patients were all interviewed on their last day (day 29) of participation in the controlled trial (Kristiansen et al., 2020).

The interview guide was developed (Table 2) and thematised based on assumptions derived from the authors’ clinical experience, logbook data from a pilot study (N = 8) and background literature on the efficacy of using weighted blankets for sleep problems in patients with psychiatric disorders, enabling the informants to express their views on the topics (Kallio et al., 2016; Kvale, 2007). The complete interview guide (Supplementary Table 2) was piloted on two trial participants using the field-testing technique (Kallio et al., 2016). The pilot produced the addition of a couple of neutral questions to the interview guide that made patients recall their feelings, thoughts and experiences at nights with poor sleep and its consequences. These questions were added to improve the accuracy and richness of the descriptions of the effect of sleeping with the PBB in the context of these experiences.

Table 2. Framing the interview guide, exemplified.

Aim	Assumptions	Theme	Interview question	Additional questions
To investigate how adult patients with depression-related insomnia experience sleeping with a PBB, focusing on how the blanket feels and works and contributes to their subjective sleep quality experience.	The changing sensory impressions from the moving balls have a calming and soothing effect on physical and mental unrest.	How does the PBB feel and how does it work.	Can you describe the importance of the fact that the balls are placed loosely within the blanket and can move around?	What do you feel when you move under the blanket (e.g. when you turn)? How does your body react to the blanket? How does that feel? What significance do you find that the changing sensory impressions have? Please provide some examples, if possible. Do you find that the moving balls are an advantage or a drawback? Can you explain in a bit more detail, please?
	It is easier to fall asleep when sleeping with a PBB.	Patients’ sleep quality experience with the PBB.	Please tell me how you experienced falling asleep when you were using the ball blanket?	How did you experience falling asleep (the period until sleep sets in)? Did you find it was easier or more difficult to fall asleep with a ball blanket than with your own duvet? Can you please describe in more detail? Did you experience a difference with respect to how long it took for you to fall asleep compared with when you were with your own duvet?

The interview guide comprised three themes: 1) Background information on how, when and why the sleep problems started; patients’ knowledge about weighted blankets and their individual expectations for results; 2) Information about how the PBB feels and works; and 3) Patients’ sleep quality experience with the PBB. The interview guide was used flexibly, encouraging a dialogue during the interview (Kvale, 2007). Questions varied between open introductory questions, follow-up questions and questions of a probing, specifying, directing, structuring and interpreting nature (Kvale, 2007). The interview process was continuously discussed with MB to ensure reliability.

All interviews were digitally recorded and transcribed verbatim by STK and a research assistant. Transcriptions were based on written instructions including instructions on how to transcribe emotional expressions like laughter, sighing and pauses, changes in breathing, vocal pitch or tone of voice (Graneheim & Lundman, 2004; Kvale, 2007; Schreier, 2012). Audio recordings and transcripts were treated confidentially and securely stored in the REDCap (REDCap 8.5.22 2019 Vanderbilt University) system. Furthermore, the participants were anonymised in transcripts used for further processing.

Data analysis

The transcripts were analysed in a four-step process in accordance with inductive content analysis methodology (Dey, 2005 Elo & Kyngäs, 2008; Elo et al., 2014; Erlingsson & Brysiewicz, 2017; Graneheim & Lundman, 2004; Lindgren et al., 2020; Schreier, 2012). Both manifest and latent content were analysed (Graneheim & Lundman, 2004). Firstly, STK read the transcripts several times to obtain an overall understanding and noted initial considerations in a logbook. Secondly, meaning units, i.e. statements informing about the study aim were identified and sorted using two analytical questions: 1) What is the patient’s perception of how the ball blanket feels and how it works? 2) What is the patient’s subjective sleep quality experience with the PBB? (Graneheim & Lundman, 2004). To ensure the reliability of the final unit of analysis, two coders (STK and MB, each of whom respectively possess clinical and methodological experience with the subject field) independently extracted meaning units from three randomly selected units of the transcripts to assess inter-rater reliability (IRR) (Graneheim & Lundman, 2004; McAlister et al., 2017). The IRR between coders was 93.3%. Thus, the two coders extracted the same meaning units from the text to the recommended degree (80–90%) (Graneheim & Lundman, 2004; McAlister et al., 2017). Diverging coding decisions mainly stemmed from STK, who generally included more context to each central meaning than MB did (Graneheim & Lundman, 2004). The process was repeated until a consensus was reached that no further relevant data had been inadvertently or systematically excluded and that no irrelevant data had been included (Graneheim & Lundman, 2004). Subsequently, STK extracted meaning units from the remaining transcripts. Thirdly, the derived meaning units were condensed, labelled with a code, analysed focusing on commonality in meaning and assigned to four descriptive categories. During this analytical process, notes from the transcripts and logbook were used to capture the latent content and to contextualise meaning units. Examples of meaning units and codes are shown in Table 3. Fourthly, the categorised meaning units were compared to identify meaningful patterns of regularities and variations; and two explanatory theme(s) emerged, explaining how adult patients with depression-related insomnia experienced sleeping with a ball blanket (Graneheim & Lundman, 2004). Examples of codes, categories and themes from the analysis are presented in Table 3. The entire analytical process was conducted in constant dialogue between STK and MB to strengthen the credibility and dependability of findings, categories and themes; finally, the findings were discussed with psychiatrists PV and ERL (Bengtsson, 2016; Elo et al., 2014; Schreier, 2012).

Table 3. The analytical process, exemplified.

Analytical questions	Meaning units	Codes	Categories	Themes
1. What is the patient’s perception of how the ball blanket feels and how it works?	“I think like I felt calmer, and I had more time to fall… fall asleep given the fact that I spent a lot of my time on… in the past overthinking and being mean to myself. With the ball blanket, I just felt that… that now it was time to sleep. And then I kind of started thinking less and giving my brain room to go to sleep”. “You turn a little bit, the balls also move, and then you are like well, how funny they move too, and now they lie a little differently […], so the fact that the balls also move when you start to get uneasy, and then you remember that you are lying with it (the PBB) […] then I think about it (the PBB) a bit and then I get a little bit distracted”.	The ball blanket induces calmness and removes attention from negative thoughts. The movement and dynamic touch of the balls creates a distraction when feeling unrest.	Changing sensory impressions from the rolling balls distracted attention from distressing thoughts and emotions.	The calming and relaxing feeling of deep pressure stimulation from the rolling balls reduced physical and mental unrest.
2. What is the patient’s subjective sleep quality experience with the PBB?	“I fell asleep faster, and I wasn’t so marked by restlessness when I was lying down having to fall asleep”. “I don’t feel like I’ve had that many awakenings. I think I woke up less. But I also think that the duration was shorter because I didn’t register it, so it may well be a mix…so I just somehow feel like I’ve slept so… heavier that I may not have registered that I’ve woken up”.	Reduced sleep onset latency. Reduced number and length of nocturnal awakenings.	The ball blanket improved the quality and quantity of sleep, which increased daily well-being.	The weight and the changing sensory impressions from the rolling balls promoted the experience of better sleep quality.

Results

The analysis revealed four categories describing how adult patients with depression-related insomnia experience sleeping with a PBB, focusing on how the blanket feels, how it works and its perceived effect on their subjective sleep quality experience: (1) Deep and dynamic touch pressure from the plastic balls induced calmness; (2) Changing sensory impressions from the plastic balls distracted attention from distressing thoughts and emotions; (3) The ball blanket improved the quality and quantity of sleep, which increased daily well-being; and (4) Sleeping with the ball blanket was associated with both positive as well as negative experiences depending on personal preferences for sensory stimulation.

Deep and dynamic touch pressure from the plastic balls induced calmness

The heaviness and pressure of the dynamic rolling balls inside the duvet cover induced calmness as the deep-touch pressure felt like a massage that put pressure on the muscles, joints and skin in a way that relaxed their bodies. Patients’ bodily muscle tensions, unease, restlessness and usual feeling of inability to relax when trying to fall asleep were thereby diminished. For some patients, the weight and pressure of the rolling balls reduced their physical unrest and anxiety before falling asleep as the balls provided a pleasant, soothing feeling of being embraced, enveloped or encircled in a way that felt like a hug, calming their bodies down and making it easier for them to relax.

“It’s almost the same as when you get hugged. Yes, you know what I mean. It’s a nice feeling. Well, I feel surrounded […] As if someone is holding me. When the plastic balls land on my body, I can relax better”. (Participant 11, male, 56 years)

The soothing and embracing feeling of the loose balls moving in step with the patient’s movements underneath the blankets triggered a feeling of lying under a heavy shield, in a secure tunnel, a safety bobble, a protecting cave or capsule that made patients feel secure, protected and safe from worry and fear about everyday situations, relieving physical symptoms caused by anxiety. Such feelings made it easier to lie still, find rest and prepare for sleep.

“It’s also kind of like a little capsule because it’s so heavy, so it just covers you like that, and then you kind of lie in your own little cave. And it’s kind of cosy (laughs), and it’s kind of heavy on you, so that’s how it weighs down against you and kind of protects you”. (Participant 9, female, 19 years)

The deep touch pressure and the heaviness of the PBB made patients feel a calmness in their bodies, which helped them overcome nights with excessive tossing and turning before falling asleep. The heaviness created a positive feeling of being pressed or almost held down, like a fixating feeling that made patients feel physically exhausted, making them give up moving. For others, when sensing the heaviness of the PBB, it was more as if the body just knew it was time to relax, making the patients feel less uneasy and making it easier to settle down, remain quieter and find peace before falling asleep.

“I have been less uneasy, and I think that I have tugged in a lot more quietly. At least I have a feeling that I have not had the need to toss and turn 50 times before I go to sleep, but I can just settle for maybe three times. Less tossing and turning and quicker to find ease. I have been very uneasy before, and it (the PBB) helped me settle down and find peace”. (Participant 8, female, 22 years)

Changing sensory impressions from the rolling balls distracted attention from distressing thoughts and emotions

The movements and sensations when patients turned underneath the blanket distracted their constant negative thoughts due to their overactive brain, making them less likely to dwell on negative thinking about themselves, the world and the future, helping them feel less psychological unrest, making it easier falling asleep.

“I think like I felt calmer, and I had more time to fall… fall asleep than previously when I spent a lot of my time on…, in the past, overthinking and being mean to myself. With the weighted blanket, I just felt that… that now it was time to sleep. And then I kind of started thinking less and giving my brain room to go to sleep”. (Participant 6, male, 24 years)

Moving underneath the PBB helped the patients to shift their focus away from rumination towards their bodies when waking up during night hours experiencing rumination such as repetitive and passive negative thinking. The moving made it possible to break the spiral of constant negative thoughts owing to the bodily distraction which helped them put their mind at rest, making it easier for them to fall back into sleep.

“You turn a little bit, the balls also move, and then you are like, well, how funny they move, too, and now they lie a little differently […], so the fact that the balls also move when you start to get uneasy, and then you remember that you are lying with it (the PBB) […] then I think about it (the PBB) a bit and then I get a little bit distracted”. (Participant 9, female, 19 years)

The PBB contributed to pause, escape or replace negative thoughts by an improved bodily focus. The deep-point and varied touches from the balls as patients turned underneath the blanket made the patients occupy their brain with how their bodies were doing as the sensation of the PBB enhanced their bodily awareness and made them register their bodies’ boundaries instead of, e.g. focusing typically on negative self-blame about what had occurred during the day and in their past. The pause or escape from negative thinking was equated with doing mental exercises like counting sheep or doing deep breathing exercises, signalling to the body that it should relax and go to sleep.

“How is my body doing instead of everything else. Such as what has happened during the day and what happened there and there, so I have kind of used it almost as counting sheep or taking deep breaths […] instead of lying around thinking about all sorts of stupid things”. (Participant 9, female 19 years)

Some patients laid on top of the blanket to achieve stimuli and a massage sensation during the day, which helped them feel their whole body. This made them sense their arms, legs, chest, bag and toes when they needed to distract their attention from overactive thoughts, sadness, suicidal ideations and other negative emotions, causing physical unrest such as chest pain, hyperventilation and other anxiety symptoms. Thus, patients achieved a relaxing and grounding feeling when laying on top of the blanket, which relieved stress and anxiety.

“I feel like I am other than my uneasiness […] you get a different touch, that is… you just feel yourself, you feel like okay, well I also have a back and I have… you know like when you take your shoes of, and you connect with the ground […] it is not only uneasiness, like that discomfort I kind of get around the chest and such. I cannot be in myself, and then I kind of get the grounding somehow. Then I feel okay my arms and my legs are there too… My body is there, too”. (Participant 3, female, 25 years)

Some patients experienced a return of negative thoughts and physical turmoil when returning to sleep with their own duvets after the intervention period with the PBB had concluded. This gave them a feeling of hopelessness and, in one case, suicidal thoughts returned.

“The first nights after I had gone back to my own duvet, I felt incredibly restless. I had a hard time finding peace. My mind was racing. And they (her thoughts) became more negative; more and more focused on how I could get away from the world and stuff like that. Just hurting myself. Because then people could … um, maybe people could see how bad I felt”. (Participant 12, female 41 years)

The ball blanket improved the quality and quantity of sleep, which increased daily well-being

The sensory inputs from the blanket induced calmness and alleviated psychological unrest, which positively influenced patients’ quality and quantity of sleep. Furthermore, most patients experienced that the blanket reduced their sleep onset latency or increased their total night-time sleep by reducing the number and length of nocturnal awakenings. A more cohesive sleep increased their daily well-being, allowing them to feel more rested in the morning and having more energy during the day. When feeling calmer, relaxed, secure and distracted from negative thoughts, it was easier to fall asleep.

“I fell asleep faster, and I wasn’t so marked by restlessness when I was lying down having to fall asleep”. (Participant 7, female, 24 years)

Some patients feared having to return the blanket at the end of the trial because it helped them to relax more and fall asleep faster, so their gratitude for better sleep was mixed with a concern that their sleep problems would return.

“I still had a bit of a hard time falling asleep […]. I may have been lying for half an hour, where I struggled to fall asleep, maybe half an hour to an hour. Instead of the one and a half to two hours it has sometimes been. So, you could say. Uh… I have been a little sad to have to hand in the PBB again. (The patient starts crying, turns his head away, tears fall down his cheeks) […] Yes, yes, because (cries)… yes, because I think it has just done something to me. I have been able to relax better. The last week or so, it has improved. I would put it this way: With my sleep… or what to say. Falling asleep. So, my falling asleep has improved”. (Participant 11, male, 56 years)

Most patients experienced an increase in total sleep time. Awakenings were perceived as fewer and of shorter duration, and early morning awakenings were reduced. Moreover, when the patients did wake up, it was easier for them to fall back to sleep. Few patients experienced an adaption period with the blanket, experiencing an increase in nocturnal awakenings during the first week as they woke up due to difficulties manoeuvring the PBB. The second week, they experienced a more consistent sleep with fewer awakenings than usual. A reduction of awakenings and less wakefulness after sleep onset caused less toilet visits, less wakeful hours in the kitchen, less restless downtown walks listening to podcasts, less early morning awakenings lying in bed waiting for the alarm to go off, and feelings of less dream activity and fewer nightmares. Patients experienced a feeling of calmer and deeper sleep with fewer awakenings; and if awakenings did occur, they did not last long enough to be bothersome.

“I don’t feel like I’ve had that many awakenings. I think I woke up less. But I also think that the duration was shorter because I didn’t register it, so it may well be a mix…so I just somehow feel like I’ve slept so… heavier that I may not have registered that I’ve woken up”. (Participant 3, female, 25 years)

The feeling of falling asleep more easily and staying asleep improved patients’ daily well-being and daytime functioning. They felt calmer, more relaxed, fresher and more rested in the morning, which allowed them to improve their mood and heighten their energy during the day.

“I was kind of rested and was in a good mood. Woke up and was in a good mood. It’s so strange to me because it’s often just like “shit”, another day. I can’t. I’m so tired, when can I go back to bed?” It’s really crazy to wake up and be rested. That’s what I thought about the most”. (Participant 7, female, 24 years)

According to their relatives, the patients were more relaxed in the morning after sleeping with the PBB, e.g. their bodies did not shake right away, they smiled in the morning and were not completely exhausted. Furthermore, the patients felt more on top of their head when they got up in the morning, e.g. experienced less abandonment when their children had to be woken up in the morning and sent to school. More energy to just sit with the children and be present was also noted by relatives. Most patients felt that they had more energy, which produced a positive effect on their ability to concentrate, manage their studies, walk the dog, engage with colleagues and constructively work on their anxiety, etc. Some patients even experienced being happier when sleeping with the blanket.

“I was somehow happier and had a little more surplus to live and not just surplus to being alive, as I said before, it has given me something… somewhat… some more joy… when I have slept well […]. And I’ve been for the past week or so, I feel like I’ve been a little happier… and had a little more energy to work with some anxiety. So, it has been such a nice breath of air… a positive puff… So, there’s been a little more room to work with some anxiety… I think it’s just because I don’t feel like I’ve uh woken up so many times that I’ve kind of been more refreshed in my head to have the energy to say; okay well today I’m doing this work on my anxiety, and then still have a good day. So, there’s kind of been more energy to work on myself (laughs lightly)”. (Participant 3, female, 25 years)

However, a minority of patients experienced no impact of the PBB on daily well-being.

“It was just suddenly a completely different sensation than I was used to. And the thing about knowing… that the weight (from the PBB) was… so it was something I actually felt was very positive. Erm… but then again, so I've had many awakenings, and I've still been really bothered by it, and it’s also affected me in my daily life. Erm so… I haven’t immediately been able to see that my sleep has either improved or worsened my daily well-being, so I've actually felt it…much the same”. (Participant 11, male, 56 years)

A few patients also found that it became harder to get up in the morning as the heaviness and enveloping feeling of the blanket entailed that they stayed in bed with a desire to just stay put and keep sleeping.

“It takes a little bit more motivation to get out of bed. Erm…because you don’t just jump out of bed when the alarm goes off. Erm, so it’s like it (the PBB) will help you stay in bed and sleep, but that might not be. so smart if you have to get up and go to work. But I'm actually good enough to get up when I have to. Erm… it hasn’t been a major challenge, but it’s like motivation to get up has been less (with the PBB)”. (Participant 10, male, 60 years)

Some patients noted taking fewer sleeping pills or other sedatives during the 2-week intervention period. Some reduced their use of Quetiapine, Risperidone or Zopiclone as they could calm down without taking these drugs, whereas others found that the PBB had no impact on their medication use as they took their sleeping pills or sedatives as ordered during the trial period.

“Especially Risperidone, I have taken less of. And Zopiclone […]. And I have definitely taken less of that because I’ve just been less restless”. (Participant 7, female, 24 years)

“It hasn’t crossed my mind while I’ve had the weighted blanket at least… that I have had to take the medicine. But it did … but it has many times with my normal duvet”. (Participant 8, female, 22 years)

Sleeping with the ball blanket was associated with positive as well as negative experiences depending on personal preferences for sensory stimulation

Both positive and negative associations were identified in relation to sleeping with the PBB depending on the patients’ personal sensory stimulation preferences. The weight, temperature, adaptation period to the PBB and, in general, the loose plastic balls in the blanket were perceived differently. Some patients found that the weight of the blanket was suitable with the 7 kg evenly distributed throughout their body, whereas others had a preference for a heavier model preferring more weight from the hip all the way up to the neck putting more deep-touch pressure on the upper body.

“But I don’t think I’ve been able to feel it (the PBB) that much on the upper body. Erm… and maybe I would really like to do that. That it was more obvious… on the upper body”. (Participant 10, male, 60 years)

“I would like one (a PBB) that was a little heavier to… get like… not a numbing feeling, but what should I say, about such a weight on… well, it’s not unpleasant, it’s just… (sighs) nice”. (Participant 7, female, 24 years)

Half of the patients worried that the PBB would be too warm due to its thickness, but found the temperature underneath the blanket to be nice and cool or neutral, adapting to their body temperature. Specifically, it was associated with positive experiences that patients avoided waking up drenched in sweat.

“I didn’t sweat … so I didn’t feel that at any time I had those sweats … hot flashes that I have… I really usually have a lot of that. And especially when I sleep with my boyfriend, I usually wake up and sometimes drenched in sweat. But I don’t think so at all … at least not from what I can remember in the last 14 days that I did. Erm… so it was much cooler and … and nice, actually. In other words, such a positive experience that… that it wasn’t so stuffy.” (Participant 8, female, 22 years)

“I had a bit of fear that the duvet might be very warm because it looks thick. Uh … but luckily it turned out not to be, it feels a lot like lying with a normal duvet … uh, in terms of temperature. Erm… and it was one of those things that I was a little skeptical about. I thought that I wouldn’t be able to sleep because of the heat. But that … that was okay”. (Participant 4, male, 26 years)

In contrast, some patients felt that the blanket was too cold. Some patients occasionally needed to put a blanket on top of the PBB to keep warm. These patients slept with the blanket in the months from November to April. None of the patients who used the blanket from May to October had problems keeping warm.

“Erm, I think it was too cold to sleep with it. Because I don’t think there was any heat in it. So, I actually had a blanket over me so I could sleep at all”. (Participant 12, female, 41 years)

The adaptation period to the blanket lasted from one to seven days, meaning that some patients woke up more than usual in the first days, mostly experiencing manoeuvring problems due to the blanket. Some, especially the ones sleeping on their side, noticed that they could not use the PBB to tuck between their legs due to the size and hardness of the balls. A minority noted that they needed to get used to the blanket, for example being so thick, and that their arms were better tucked underneath than above it as it did not feel comfortable. Few also experienced that the blanket fell over the edge of the bed due to its weight, and some simply just found that the blanket was excruciatingly heavy during the first few nights; as if they were being held down. But after a few nights of sleep, when they were getting used to the PBB, the majority of patients experienced no bother adapting to the sensations of the PBB and had a general feeling of fewer awakenings than initially.

“So uh… getting used to sleeping under it, I’ll say you certainly do. And it has gotten better and better over time… and in that way 14 days may actually be the shortest time to sleep with it… uhm to feel such an effect of it. And I actually managed to move along the way in that experiment here in 14 days…But what I would say is that the effect of it has been clearer and clearer as the days have gone by”. (Participant 10, male, 50 years)

The flexible design of the moveable balls inside the duvet cover made it easier to move underneath the blanket, and the sensations positively helped patients to reduce mental and physical unrest. Even so, a few patients believed that they woke up due to the movements of balls the first couple of days and overall had a feeling that they would have preferred a calmer or softer model with only the weight and not the changing deep-touch-pressure from the moving plastic balls as they felt overstimulated with impressions from the blanket. Some patients found that the blanket took up too much space in the bed, why a minority of patients or bed partners moved to another room to sleep. Furthermore, the PBB stopped couples from cuddling up together.

“I haven’t actually slept with it the last few nights. Because I couldn’t really stand it anymore. At first… when I lay there and had it laid down on me I think it was great. But in the end, as I say, I just couldn’t handle it there. It was also because my wife said it’s simply in the way. It takes up too much space for her as well. And we couldn’t lie down together because she simply gave up approaching me. And so did I because I couldn’t lie down under her duvet. Because it was too unwieldy”. (Participant 13, male, 62 years)

Generally, the soft sound of the balls hitting each other was not bothering or disturbing for patients, though a minority of bed partners found that it bothered their sleep due to the sound appearing every time the patients moved due to unrest. Some patients liked that the plastic balls served as a shield against the movements of their bed partner, which ensured that they did not disturb the patients’ sleep. Despite the negative associations, most patients would use the PBB for sleep every day, whereas others suggested using the PBB on an as-needed basis for sleep problems and as a relaxation-inducing aid during the day when feeling unrest. A common view among the patients was a belief that other people with depression and sleep problems would also benefit from its use.

“Just what it has given me, even if it… it’s not… not miracles, but it has done a… So I have noticed a difference, so… I think it may make a difference to others too”. (Participant 3, female, 25 years)

Discussion

The transversal analysis (Dey, 2005; Graneheim & Lundman, 2004; Schreier, 2012) of the categorised meaning units revealed two explanatory themes related to sleeping with a PBB: 1) The calming and relaxing feeling of deep pressure stimulation (DPS) from the rolling balls reduced physical and mental unrest, and 2) The weight and the changing sensory impressions from the rolling balls promoted the experience of better sleep quality. These themes show that the embracing pressure from a PBB was perceived to induce a sense of calmness and relaxation, alleviating both physical and mental turmoil such as anxiety symptoms, stress feeling, racing thoughts and rumination. PBBs furthermore positively influenced patients’ experience of sleep quality in terms of sleep onset latency, number of awakenings, wake after sleep onset and daytime well-being.

The calming and relaxing feeling of deep pressure stimulation from the rolling balls reduced physical and mental unrest

The PBB reduced both physical and mental unrest related to insomnia and depression. The DPS and embracing feeling from the rolling balls during sleep establishment reduced uneasiness, ruminations and anxiety symptoms. These findings are in line with both quantitative and qualitative studies using DPS from different types of weighted blankets (Champagne et al., 2015; Ekholm et al., 2020; Hjort Telhede et al., 2022; I. Larsson et al., 2021; Wallis et al., 2018). The calming feeling was supported by results from an exploratory pilot study, which found that a 30-pound weighted blanket reduced anxiety in 60% of participants during an acute mental health hospitalisation (measured by the State-Trait Anxiety Inventory-10 (STAI-10) and a self-reported 0-10 anxiety scale) (Champagne et al., 2015). The anxiety-moderating feeling is in line with the results of a randomised controlled study, which found that an 8-kg weighted metal chain blanket significantly reduced symptoms of anxiety (pre HAD-A 13.8 versus week 4 HAD-A 10.3) measured by the Hospital Anxiety and Depression Scale (HAD-A) in patients with depressive disorder, bipolar disorder, generalised anxiety disorder and ADHD (Ekholm et al., 2020). Similarly, a multiple repeated single-case design study found that six weekly sessions with an occupational therapist providing sensory treatment options, such as weighted blankets, reduced anxiety for three of the four participants (measured by the Beck Anxiety Inventory) (Wallis et al., 2018). Furthermore, in qualitative studies, fibre-weighted blankets improved relaxation and reduced anxiety among children with ADHD and sleep problems (I. Larsson et al., 2021), and weighted chain blankets reduced anxiety and worrying among residents with sleep problems in nursing homes (Hjort Telhede et al., 2022). Interpretation of these studies is, however, hampered by the small sample sizes in the quantitative studies and heterogeneity with respect to blanket type, weight and duration of use across the studies (Eron et al., 2020).

Use of the PBB had anxiety-reducing benefits as suggested by the present and previous studies (Champagne et al., 2015; Ekholm et al., 2020; Hjort Telhede et al., 2022; Larsson et al., 2021; Wallis et al., 2018). Moreover, we found that the blanket was used unrelated to sleep when some patients wanted to reduce physical and mental unrest during daytime. Patients found it meaningful to lay on top of the blanket or tucked in when experiencing anxiety, distress or rumination regardless of the time of day. Similar results have been reported in an interview study among patients with serious mental illnesses who used a sensory room with a weighted blanket or a massage chair owing to their relaxing, calming, soothing and protecting effect (Sutton & Nicholson, 2011). The patients in the present study had unipolar depression and insomnia symptoms, whereas previous studies also included patients with other mental health disorders, which may potentially point to general anxiety-reducing effects of the PBB independently of psychiatric diagnosis.

The weight and changing sensory impressions from the rolling balls promoted the experience of better sleep quality

The deep proprioceptive stimulation improved subjective sleep quality for some patients, including reduced sleep onset latency and fewer and shorter nocturnal and early morning awakenings. The sleep was perceived as being deeper and calmer with less dream activity and fewer nightmares. This positively affected their daily well-being as these patients reported feeling fresher and more rested in the morning. These results are in line with those of four previous studies (Ackerley et al., 2015; Ekholm et al., 2020; Hvolby, 2020; Hvolby & Bilenberg, 2011): A randomised controlled trial in adult patients with bipolar disorder, major depressive disorder, ADHD or generalised anxiety disorder found better Insomnia Severity Index (ISI) ratings after sleep with weighted chain blankets than after sleep with light plastic chain blankets (pre ISI 21.7 versus week 4 ISI 9.2) (Ekholm et al., 2020). Among the secondary outcomes, the weighted chain blanket was associated with better sleep maintenance, higher daytime activity level and reduced daytime symptoms of fatigue, anxiety and depression (Ekholm et al., 2020). A repeated-measures study in patients with chronic insomnia found that a weighted chain blanket increased sleep bout time and reduced activity score (Figure 1 in ref, (Ackerley et al., 2015)), and that use of a weighted chain blanket was associated with, e.g. self-reported calmer nights’ sleep and a feeling of being more refreshed in the morning (Ackerley et al., 2015). Two case-control studies investigating ball blankets in children with ADHD found that sleep onset latency and ADHD scores were reduced and daily level of functioning and quality of life were improved (Hvolby, 2020; Hvolby & Bilenberg, 2011). The findings from our study, similarly to those seen in these intervention studies, corroborate that weighted blankets improve patients’ sleep, daily well-being and daytime functioning. In our study, the positive experiences with the PBB outbalanced the negative experiences for the 13 included patients when evaluating the weight, temperature, adaptation and design of the PBB. Importantly, our study suggests that the overall benefit of PBBs depends on the patients’ preferences for sensory stimulation. To accommodate or minimise the negative experiences (e.g. awakenings due to difficulties manoeuvring the blanket, noises from rolling balls and feeling too cold), previous studies recommend that patients should have a choice of blankets with different characteristics available (e.g. tactile, thermal isolation and weight) (Ackerley et al., 2015; Champagne et al., 2015; Sutton & Nicholson, 2011).). Evidence, however, is limited in supporting that the weight of the blanket should relate to the mass of a person, e.g. that blankets weighing more than 10% of the person’s body are preferable (Ackerley et al., 2015).

Overall, the present study and previous studies corroborate the meaningfulness of sleeping with a PBB (in particular when the blankets are tailored to the patients’ preferences for, e.g. weight, temperature and flexible versus calm designs), and show that patients experience PBBs as a meaningful tool to improve sleep quality, but also potentially as an aid to induce calm and reduce anxiety during the day.

Limitations

This study included patients with unipolar depression, which potentially limits the generalisability of our findings to other patient groups. Other studies, however, found comparable results among patients with chronic insomnia, anxiety disorders, bipolar disorder or ADHD, which is reassuring. A further limitation is the relatively short timeframe (14 nights) sleeping with the PBB in the present study. A longer exposure to the blanket may have influenced the experience of how the blanket feels, works and affects sleep quality. Not all patients reported the same benefits from the PBB, which further emphasises the need for tailored treatment of patients with unipolar depression, and, importantly, that clinical trials are much needed.

Conclusion

The weighted PBB assisted most patients with depression-related insomnia with emotional and physical regulation and improved their subjective sleep quality experience. The benefits may partly be mediated by enhanced calmness and distractions from negative thoughts and emotions during sleep time. During the day, the DPS afforded by the ball blanket seemed to reduce the patients’ perceived mental and physical unrest unrelated to sleep. The use of DPS from the ball blanket may therefore potentially be used to reduce both sleeplessness at night and restlessness and anxiety during the day.

Ethical approval

The study was approved by the Danish Scientific Ethics Committee (1-10-72-204-18), Innovation Fund Denmark (7038-00157B) and the Data Protection Agency internally at Aarhus University (2016-051-000001, 1159) before patient enrolment and followed the ethical principles of the Declaration of Helsinki. The trial registration number from where patients were recruited: ClinicalTrials.gov Identifier: NCT03730974.

Acknowledgements

The research team takes this opportunity to express their gratitude to the participants for their willingness to share valuable experiences. Furthermore, we thank project nurses Vicki Häker Berglund and Mathilde Dalgaard, and occupational therapist Anette Bournonville Kjær Wester and consultant Susie Andersen for recruiting eligible participants for the study; and research assistant Iben Rask Heuck who assisted STK with the transcription of interviews.

We also thank the Innovation Fund Denmark, Oestergade 26 A, 4^th Floor, 1100 Copenhagen K; Protac A/S, Niels Bohrs Vej 31D, 8660 Skanderborg, and Aarhus University, Department of Public Health, Bartholins Allé 2, 8000 Aarhus C, Denmark for funding.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data are available on request due to privacy/ethical restrictions.

Additional information

Funding

This is an industry-supported study adhering to Innovation Fund Denmark guidelines for industrial PhDs. The company Protac A/S covered 50% of STK’s salary and Innovation Fund Denmark covered the remaining 50%. The funding sources had no influence on the study design, analysis, interpretation of data or the decision to submit the results. Furthermore, the study data are owned by Aarhus University.