Is internet-based psychological therapy effective for treating major depressive disorder?

KEYWORDS:

• Digital interventions
• internet-based interventions
• depression
• telemental health
• smartphone app

1. Introduction

Depression is a prevalent mental disorder [1], responsible for the largest proportion of burden among mental disorders and ranking as the 13th leading cause of disability-adjusted life years across diseases [2]. Even though there is a wide range of evidence-based treatments available, people diagnosed with depression often do not receive treatment, especially in low- and middle-income countries (LMIC) [3], where most of the world population lives. Among several barriers, such as low perceived need and attitudinal barriers, structural barriers are known to hinder depressed people from receiving adequate care [4], including lack of availability of services.

To address such challenges, leveraging digital technology for interventions has emerged as a crucial approach due to its scalability. The widespread affordability of smartphones and computers on a global scale has contributed to this potential. Moreover, digital technologies reduced geographical distances by allowing real-time communication and access to applications and software that can deliver or support mental health interventions. In the context of a stepped care approach, if internet-based interventions are efficacious, they could be incorporated into health systems [5], optimizing resources and minimizing system strain. In light of this, a question emerges: can internet-based psychological therapy be safely implemented for the treatment of depression? We will focus on two modalities of internet-based interventions: telemental health and smartphone apps.

Telemental health, or high-intensity psychotherapeutic digital interventions, is the use of telecommunications or videoconferencing technology to deliver mental health interventions [6]. It allows the delivery of psychological treatment across distances, eliminating geographical barriers. Thus, it can be more accessible, convenient, and flexible for people diagnosed with depression. In this modality, the psychotherapist conducts sessions in a similar manner to traditional in-person sessions, but using video and audio for real-time interaction.

A recent meta-analysis reviewed the literature of randomized controlled trials (RCT) comparing telemental health to face-to-face therapy [7]. Seven studies conducted in the United States were meta-analyzed, showing no statistically significant differences between telemental health and face-to-face in depression outcomes after intervention. Data also revealed no differences in quality of life outcomes and therapeutic alliance. In addition, a systematic review of RCTs addressed the acceptability, satisfaction, efficacy, and cost-effectiveness of telemental health interventions (including psychiatric treatment) [8]. Synthesis of findings from 14 RCTs showed no differences in terms of satisfaction when comparing face-to-face vs. telemental health treatments. Some studies even pointed out that telemental health could provide more satisfaction to both providers and patients. Telemental health interventions were also shown to be cost-effective alternatives to traditional interventions.

Hence, available evidence suggests that telemental health has the potential to produce similar outcomes as traditional in-person psychological therapy. However, although promising, such findings have limited generalizability – not only by the scarcity of RCTs but also by lack of evidence from LMICs. It is also unclear whether geographical location (urban or rural) can affect outcomes. Moreover, there is no conclusive evidence regarding specific subgroups with depression, such as the elderly population, people with comorbidities, and people with severe depression or at-risk for suicide, among others. Studies focused on implementation processes and outcomes are also needed to understand how such interventions can be adequately delivered in low-resource settings that are common in LMICs, where available hardware and internet bandwidth can be limited.

Smartphone app interventions, or low-intensity digital interventions, refer to the use of mobile applications (apps) designed to deliver psychological treatments remotely. It is usually based on well-known evidence-based psychological techniques that were originally developed to be delivered by therapists in traditional clinical settings. Researchers have made the effort to adapt these techniques to the digital context, typically simplifying psychological concepts to optimize learning, since not all smartphone app interventions are guided by a therapist. Such interventions typically follow a psychoeducational framework, wherein individuals gradually acquaint themselves with psychological techniques and subsequently incorporate them into their daily routines. Additionally, they typically enable users to regularly track their symptoms and behaviors, promoting self-awareness and increasing involvement in the treatment process.

In 2019, Weasel et al. investigated the efficacy of smartphone apps for various mental disorders, including depression [9]. The authors included in the meta-analysis 19 RCTs, but only 6 were specifically related to depression. Meta-analytic findings showed significant effects on depression with a moderate effect size. Interestingly, effects were only significant among studies using waitlist control, not other types of controls (e.g. active control). Recently, an umbrella review examined meta-analytic evidence regarding smartphone app interventions for a range of mental disorders. The study included 14 different meta-analyses representing data from 145 RCTs and more than 47,000 participants. Data derived from 10 meta-analyses on depression suggested smartphone apps can reduce depression symptoms, even though effect sizes were small in magnitude. Type of control group significantly impacted effect sizes. More importantly, smartphone apps did not significantly differ from active controls or adjunctive treatment. Information on adverse events related to smartphone apps was lacking. Another meta-analytic study reviewed available data from RCTs testing smartphone apps for perinatal depression, showing no significant improvement in this particular group [10].

Smartphone apps for depression are promising, but high-quality data is still lacking. Limited effect sizes of such interventions are thought to be related to app engagement. Even though more studies are needed to pinpoint the mechanisms explaining poor adherence, current evidence indicates poor usability, privacy and trust concerns, as well as lack of support during crises or human feedback, may be some of the reasons for engagement rates being low [11]. It must be noted that the dropout rate of RCTs of smartphone apps for depressive symptoms is estimated to be 47% [12]. While elevated, these dropout rates align with those observed in other mental health treatment strategies. For instance, dropout rates of around 30% have been reported in studies examining treatment retention for antidepressant medications, and approximately 47% for psychotherapy [12].

Furthermore, smartphone apps may not be suited for all subgroups of depressed people. For instance, a recent meta-analysis showed apps were not effective in reducing perinatal depression or anxiety, even though there are currently more than 70 apps commercially available to treat these conditions [10]. Depressed women in the perinatal period trying to treat their symptoms with an app can not only fail to achieve any improvement but can potentially experience worsening of symptoms and functional impairment, as well as substantially delay seeking for evidence-based treatments. There is a clear need for the development of higher-quality apps to address perinatal depression and anxiety, in addition to high-quality studies testing their efficacy. Another subgroup that warrants attention is people at-risk for suicide. Up-to-date evidence from a comprehensive meta-analysis found apps to treat suicidal ideation did not differ from control conditions [13]. This is a clear indication of the limitation of apps in dealing with safety-related crises of depressed people. Relying on such interventions could potentially lead to an increase in suicidal ideation and in worst cases, suicide attempts. Relying on such interventions may lead to an increase in suicidal thoughts, and in the most severe scenarios, result in suicide attempts. Furthermore, the literature shows that data on safety of use is lacking. Very rarely studies report data on adverse events [13]. This could be related to lack of consensus in defining adverse events in the context of digital interventions, as well as availability of an established tool to assess it [14]. Regardless, without a clear understanding of potential adverse event apps to treat depression, it is difficult to recommend them, especially to vulnerable subgroups of depressed people, including but not limited to depressed women in the perinatal period and people at-risk for suicide.

2. Expert opinion

The potential of internet-based psychological therapy, encompassing telemental health and smartphone apps, holds promise for addressing the challenge of providing effective treatment for depression. The evidence presented here suggests that telemental health can offer comparable outcomes to traditional in-person therapy, offering accessibility and cost-effectiveness. It is currently considered to be safe for clinical practice, as it is widely adopted by health systems worldwide. Meanwhile, smartphone apps show promise in reducing depression symptoms, albeit with some limitations related to user engagement and suitability for specific subgroups. Clinicians should exercise caution in prescribing this type of intervention, adhering to recommendations from regulatory agencies or guidelines from scientific associations.

Finally, to fully harness the benefits of internet-based psychological interventions, further research is needed to expand the evidence base across diverse populations and settings. A recent systematic review identified only 22 studies that tested digital psychological interventions (including telemental health, apps, and others) conducted in LMICs [15]. Thus, further work is needed to develop appropriate digital interventions able to efficiently treat depression in LMICs, especially in low-resource settings. Moreover, refining user engagement, addressing safety concerns, and tailoring interventions to better suit the needs of various subgroups of depressed people necessitate further attention and development. With nearly half of the world’s population lacking access to adequate depression treatment due to logistical, financial, and stigmatization barriers, the future of internet-based psychological therapy appears promising.

Declaration of interest

IC Passos is a CNPq research fellow. IC Passos receives authorship royalties from Springer Nature and ArtMed. IC Passos has also served as consultant, advisor, or CME speaker for the following entities: Janssen Pharmaceuticals, LundBeck, Libbs, Daiichi Sankyo, EMS, and Pfizer Inc. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

AR Brunoni receives scholarships and support from FAPESP, the Brazilian National Council of Scientific Development (CNPq-1B), the University of São Paulo Medical School (FMUSP), the UK Academy of Medical Sciences (Newton Advanced Fellowship), and the International Health Cohort Consortium (IHCC). D Fatori receives financial support from the Wellcome Leap 1kD Program. IC Passos also declares study support, in part, from the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brazil (CAPES) – Finance Code 001. This work was also supported financially by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil.