The road to diagnosis and treatment in girls and boys with ADHD – gender differences in the diagnostic process

Abstract

Introduction

The number of referrals for diagnostic assessments of Attention Deficit/Hyperactivity Disorder (ADHD) has increased in the last decade. There is a lack of studies examining the diagnostic process and the treatment provided, particularly from a gender perspective.

Methods

From a consecutive cohort of Child and Adolescent Psychiatric (CAP) outpatients, the medical records of 50 boys and 50 girls (under 18 years of age) with a diagnosis of ADHD were selected by an Excel random numbers generator. Data about referral reason, diagnostic process and treatment were analysed.

Results

Emotional symptoms were more common as a reason for referral to CAP among girls, whereas neurodevelopmental disorders were more common among boys. Compared to the boys, the girls were older at first visit to CAP and at the ADHD diagnosis. The girls had had more visits to the clinic prior to the ADHD diagnostic decision and had more often been prescribed non-ADHD medication both before and after the ADHD diagnosis. The rate of ADHD medication was similar in boys and girls. Girls had more often been admitted to a CAP inpatient care unit prior to the ADHD diagnosis due to acute psychiatric symptoms, and had received more individual psychotherapeutic counselling.

Conclusion

The results highlight the need for broader psychiatric investigations including neuropsychiatric symptoms in girls referred for ‘emotional problems’.

Keywords:

• ADHD;
• gender;
• diagnosis;
• assessment;
• emotional symptoms

Introduction

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder affecting about 5–7% children and about 2.5% adults [1–3]. The male:female ratio in children is 2:1 (2 boys in 1 girl) and in adults 1.6:1 [1]. Barkley [4] has suggested that the gender difference is even smaller and that adult ADHD is as common in women as in men.

Kopp [5] reported no gender differences in the proportion of preschool children referred to child psychiatric clinics due to behavioral problems. However, with the exception of girls with hyperactivity disorders, more boys than girls are referred for behavioral problems in school age [5]. ADHD in girls is more often identified in adolescence or in adulthood [6]. Parents and teachers seem often to fail to identify ADHD symptoms in girls, while the girls themselves report ADHD symptoms [4,6]. Reported gender differences regarding the clinical symptoms of ADHD are a higher level of hyperactivity and impulsivity in boys with ADHD [7] and higher levels of attention deficits in girls [8,9]. Anxiety and depression appear to be more common in girls with ADHD, and parents are better able to identify such problems in girls than in boys with ADHD [10,11]. ADHD symptoms are sometimes overshadowed by emotional and affective symptoms in the clinical presentation [8,9,12]. Another possibility is that girls with ADHD might have better ‘coping skills’ than boys, and that such skills might compensate and ‘hide’ the ADHD symptoms [9].

The ADHD diagnosis in clinical practice is based on the criteria according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth revised version [1]. It is recommended to involve several informants (e.g. teachers, parents), and instruments (rating scales, neuropsychological test) in the diagnostic assessment of ADHD [13]. However, the diagnosis is based on the overall clinical impression and no single instrument is exclusive for the diagnostic decision [2,14]. Recommended professions involved in the diagnostic procedure of ADHD are physicians (e.g. child and adolescent psychiatrists, pediatricians or child neurologists) and developmental psychologists with expertise in the field of developmental disorders. However, other professional’s contributions, such as special education teacher, occupational therapist, physiotherapist or speech and language therapist, are valuable not only for intervention but also in the diagnostic assessment especially in more complex cases [2,14,15]. The need to evaluate the diagnostic process has been highlighted, particularly regarding gender differences [14,16].

The recommended treatment of ADHD is to apply a multimodal approach including medication, behavioural therapy, psychosocial and pedagogic intervention as well as cognitive aids [2,4,14,17]. The treatment should be individually adapted and include the child/the adolescent itself but also the family, school and other concerned [2,4,14]. Treatment and/or support is needed throughout life, even in adulthood, regardless of gender, in the majority of the cases [18–23]. Research has shown that children with combined subtype of ADHD have more frequent contact with psychiatric care/health care [7], and that girls with ADHD more often are prescribed antidepressive medication prior to the ADHD diagnosis compared to boys [9]. However, there are no gender differences regarding ADHD medication after the diagnosis is given [13].

Research on children with ADHD is to a large extent based on samples comprised primarily of boys, and has suggested that girls with ADHD in many cases might be unidentified. This might be related to gender differences in the diagnostic process.

Aims

The purpose of this study is to examine if there are any gender differences in the diagnostic procedure and in received treatments prior to and after the ADHD diagnosis, in Swedish outpatient Child and Adolescent Psychiatric Clinic.

Methods

Selection of participants

In this retrospective diagnostic register study, 100 cases of registered ADHD (50 boys and 50 girls) were identified. They came from six Child and Adolescent Psychiatric outpatient care units (CAPs) in western Sweden (Västra Götaland region) and had been randomly identified by the health care computer system used for registration of all daily contacts. To capture the whole diagnostic process and treatment, we selected outpatients who had received their ADHD diagnosis at one of the six included CAPs and who were still in treatment at the clinic. During this period, all children in the region were referred to the CAP clinics for ADHD assessment except for a small proportion of children with permanent functional impairments that had their assessment at Habilitation Centres. The study included patients with an ADHD diagnosis (regardless of subtype), who during the year of 2015 at the age of 17 years (birth years 1997 and 1998) had at least one registered visit in any of the six included CAPs. Cases diagnosed with ADHD diagnoses prior to referral were excluded.

The original selection yielded 155 unique patients, 96 (62%) boys and 59 (38%) girls. By using a random numbers generator program in Excel, we selected 50 medical records for each gender.

The patient data, registered in the medical record system, was collected from the time of referral until the preset endpoint for data collection (30^th June 2016). All patient files were anonymised.

Data

The following data, in addition to the first registered ADHD subtype diagnosis, was retrieved; i) referral instance, ii) reason for referral, iii) age (years) at first visit to the clinic, iv) number of visits before receiving an ADHD diagnosis, v) age (years) when receiving the ADHD diagnosis, vi) type of professionals involved in the diagnostic procedure, vii) received psychotherapy prior or after diagnosis, viii) received medication prior or after diagnosis, and ix) inpatient care prior or after diagnosis. Number of visits did not include inpatient care. Referral instance was split into five alternatives; parents, school, social services, other health care clinics, or from the youth itself. Reasons for referral were defined as the initial referral questions stated in the written referral. The reason for referrals was categorised into eight alternatives; 1) symptoms of ADHD (e.g. hyperactivity and attention deficits) or demand for a neurodevelopmental assessment; 2) emotional problems (e.g. anxiety, depression, self-injurious behaviour or eating disorders); 3) family related problems; 4) school problems (e.g. reading and writing difficulties); 5) externalising problems (e.g. behavioural problems/aggression); 6) major psychosocial traumatic experiences; 7) drug abuse; 8) other reasons not included under referral reasons 1–7 above.

Psychotherapy, both prior to and after the diagnostic decision, was categorised according to five alternatives; 1) individual counselling, 2) family therapy, 3) parent counselling/training, either individually or in group, 4) combination of 1–3 above, 5) no psychotherapy at all. Families who received both family therapy and parent counselling were categorised into the ‘family therapy’ group. Follow-ups of prescribed medication by a nurse was not registered as individual counselling. Prescribed medication was categorised into 1) ADHD medication (e.g. methylphenidate, lisdexamfetamine, atomoxetine or guanfacine) or 2) non-ADHD medication (e.g. for anxiety, depression or sleep disorder). It was also recorded whether or not the medication had been prescribed prior to and/or after the diagnosis of ADHD.

Statistical analyses

All data analyses were performed by using SPSS statistics, version 25. The alpha levels were set at p < .05. All analyses were two-tailed. Independent sample t-test was used for continuous variables. When Kolmogorow–Smirnov statistic indicated a not normally distributed data, the non-parametric alternative to t-test for independent samples, the Mann–Whitney U test, was used. Chi-square test for independence was used for categorical variables. In all 2 × 2 tables, we used the Yates Continuity Correction. In cases with a low expected cell frequency, we used correction with Fisher´s Exact Probability test.

Ethics

The study was approved by the Human Ethics Committee at the Medical Faculty, University of Gothenburg, Sweden, registration number 902–16, and have therefore been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. Register data was obtained without individual consent, but only after permission from the Ethical committee where the scientific merit/benefit to patient outcomes has been assessed as sufficient to warrant such an approach.

Results

Referral procedure

There was a statistically significant difference between girls and boys regarding reasons for referral. Neurodevelopmental disorders were more common as a distinct question in boys compared to girls (x² (1, n = 100) = 16.1, p < .001). The most common question for referral in girls was emotional symptoms (x² (1, n = 100) = 16.8, p < .001). Treatment for traumatic experiences was the reason for referral in four girls, while none of the boys was referred for that reason. Substance abuse was not a reason for referral in any participant.

No statistically significant difference between the genders was found regarding referral instance. For both girls and boys, most referrals came from parents and secondly from school (Table 1).

Table 1. Reasons for referral and the diagnostic procedure.

	Girls n = 50 (%)	Boys n = 50 (%)
Reasons for referral
Neurodevelopmental disorders***	13 (26)	34 (68)
Emotional disorders***	20 (40)	2 (4)
Family related problems	2 (4)	2 (4)
School problems	1 (2)	2 (4)
Externalising problems	5 (10)	8 (16)
Traumatic life experiences	4 (8)	0 (0)
Drug abuse	0 (0)	0 (0)
Multiple reasons for referral^a	5 (10)	2 (4)
ADHD subtype^b
ADHD combined	8 (16)	12 (24)
ADHD predominantly inattentive	19 (38)	13 (26)
ADHD predominantly hyperactive	0 (0)	2 (4)
ADHD unspecified	23 (46)	23 (46)
Diagnostic procedure	Mean (SD)	Mean (SD)
Age at first visit (years)*	12.7 (3.1)	11.4 (3.0)
Age at ADHD diagnosis (years)**	15.6 (2.2)	14.0 (3.0)
Months from first visit to diagnosis	36.1 (32.9)	31.9 (30.2)
Number of visits*	35.4 (47.0)	20.9 (32.6)

Significant difference between gender at *p < .05, **p < .01, ***p < .001.

^aMultiple causes listed in the table (except suspicion of neurodevelopmental disorders).

^bCoded ADHD diagnosis in the medical journal.

Diagnostic procedure

There was a significant gender difference in age at the time of the first visit to CAP, with girls being older than boys (M = 12.7 years, SD = 3.1, versus M = 11.4 years, SD = 3.0, t (98) = 2.1, p = .037). Girls were also older than boys when they received the ADHD diagnosis (M = 15.6 years, SD = 2.2, n = 50 versus M = 14.0 years, SD = 3.0, n = 50, U = 851.5, z = −2.8, p = .006). The mean age in the whole sample (n = 100) was 14.8 years (SD = 2.7) at the time when the ADHD diagnosis was given. The mean time that elapsed from the first visit to diagnosis was 35.7 months (SD = 30.0) with no significant gender difference (Table 1).

In the whole sample (N = 100), the median number of visits at CAP from first visit to diagnosis was 15.5. However, girls had more visits at CAP from the first visit to diagnostic decision compared to boys (Md = 18.5, n = 50, versus Md = 12.5, n = 50, U = 960.5, z = −2.0, p = .046).

Beyond physician and psychologist, the same professional categories were involved in the diagnostic procedure regardless of the child’s gender. However, two girls did not meet any psychologist prior to the diagnostic decision and one girl did not meet any physician before the diagnosis was registered in journal. All boys in the sample met a psychologist before the diagnostic decision and one boy did not meet a physician before the diagnosis was registered in journal.

The ADHD diagnosis in the study group was ADHD combined type in 8 (16%) girls and in 12 (24%) boys, ADHD predominantly inattentive type in 19 (38%) girls and in 13 (26%) boys, and predominantly hyperactive type in 2 (4%) boys. No girl received ADHD predominantly hyperactive type as the first ADHD diagnosis. ADHD unspecified type was the initial ADHD diagnosis for the remaining 23 (46%) girls and 23 (46%) boys participant. No gender difference was found regarding ADHD subtype (Table 1).

Treatment received before ADHD diagnosis

More girls than boys received non-ADHD medication before ADHD diagnosis (x² (1, n = 100) = 12.9, p < .001). A subgroup had received ADHD medication prior to the final ADHD diagnosis, but no gender difference was found in this regard. No gender difference was found in terms of individual counselling, family therapy or parent counselling/training. However, girls had more often received a combination of both individual counselling and family/parental therapy (x² (1, n = 100) = 9.4, p = .002) compared to boys.

Twelve girls had been admitted to a CAP inpatient care unit prior to the ADHD diagnosis was given, but none of the boys (x² (1, n = 100) = 11.5, p = .001) (Table 2). Three of these girls received the ADHD diagnosis during the inpatient care, the remaining received the ADHD diagnosis in the outpatient care.

Table 2. Treatment before/after ADHD diagnosis.

	Girls	Boys
	n = 50 (%)	n = 50 (%)
Before ADHD diagnosis
Non-ADHD Medication^1,**	26 (52)	8 (16)
ADHD medication	6 (12)	8 (16)
Individual counselling	4 (8)	3 (6)
Family therapy	5 (10)	8 (16)
Parent counselling/training^2	0 (0)	4 (8)
Individual + family/parent*	28 (56)	12 (24)
No psychotherapy at all	13 (26)	23 (46)
Inpatient care**	12 (24)	0 (0)
After ADHD diagnosis
Non-ADHD Medication^a,*	35 (70)	19 (38)
ADHD medication	47 (94)	49 (98)
Individual counselling*	14 (28)	2 (4)
Family therapy	2 (4)	8 (16)
Parent counselling/training^b	5 (10)	6 (12)
Individual + family/parent	15 (30)	19 (38)
No psychotherapy at all	14 (28)	15 (30)
Inpatient care	6 (12)	6 (12)

Significant difference between gender at *p < .01, **p < .001.

^aAll types of medication subscribed by psychiatrists at CAP except ADHD (often for anxiety and/or depression).

^bIndividual or in group.

Treatment received after the ADHD diagnosis

ADHD medication was prescribed to the majority of the study group after the ADHD diagnosis has been established. Only three girls and one boy did not receive ADHD medication after the ADHD diagnosis. Even after the ADHD diagnosis had been given, more girls than boys received non-ADHD medication (x² (1, n = 100) = 9.1, p = .003). With regard to psychotherapy after the ADHD diagnosis, there was a significant gender difference. Girls received individual therapeutic counselling more often than boys (x² (1, n = 100) = 9.0, p = .003). No gender difference was found after the ADHD diagnosis was given regarding the prevalence of inpatient care due to psychiatric problems.

Discussion

The purpose of this study was to examine if there were gender differences in the diagnostic assessment procedure of ADHD and received treatments prior and after diagnosis in a CAP setting. We found that the reason for referral was different across genders. Girls were more often referred to CAP due to suspected emotional problems and boys had more often a primary referral question formulated as symptoms of neurodevelopmental disorders. Girls were older than boys when they first visited the clinic and when the ADHD diagnosis was given. Girls also had more visits at the clinic before the ADHD diagnosis was given. No gender difference was found regarding ADHD medication, but that girls more often received non-ADHD medication, usually for emotional symptoms, both before and after the ADHD diagnosis had been given. Before the ADHD diagnosis, girls more often than boys had received a combination of individual counselling and family/parental treatment. Girls also more often received individual counselling after the diagnostic decision. Before the ADHD diagnosis was given, more girls had been inpatients due to their psychiatric problems. Finally, the same professional categories were involved in the assessments regardless of the child’s gender.

There was a gender difference in age for the first visit at the clinic. A possible explanation is that symptoms in girls are perceived as less serious than in boys, or that boys with higher levels of hyperactivity and impulsivity more often show behavioural symptoms with greater impact on the surrounding contexts, leading to a more urgent need to assess.

We also found that most of the girls were referred to CAP during adolescence due to emotional problems. It seems that ADHD often coexists with emotional symptoms in girls [5,9,24]. Girls with ADHD have been reported to have more emotional problems than boys with ADHD and more than girls with high level of ADHD symptoms (but not fully meeting ADHD criteria) [25]. This might be explained by that a higher burden of emotional problems are required before the ADHD diagnosis is met in girls. Another explanation might be that ADHD symptoms in girls are not recognised by teachers and/or parents until they are older and thereby have increased emotional problems. A hypothesis by Kopp [5] is that girls with ADHD, in the teens no longer can compensate for and hide their symptoms by developed ‘coping strategies’. This could also contribute to increased emotional problems for teenage girls. O’Brien et al [26] report that girls earlier than boys develop a higher cognitive maturity during the school age. This gender difference is reduced in adolescence. Maybe, the functional difficulties for girls in adolescence are easier to compare with the ADHD symptoms seen in boys of the same (adolescent) age. Another interesting possibility is the impact of the female hormone fluctuations during puberty, which contributes to a more obvious degree of functional difficulties and more prominent symptoms among girls in the adolescence [24].

Several studies have highlighted the association between an ADHD diagnosis and problematic peer functioning [7,8,27]. Furthermore, difficulties related to social interaction are often associated with a higher degree of anxiety and depression as well as a low self-esteem in girls [8,9,27]. The gender difference in respect of individual counselling, higher rate of non-ADHD medication (mostly for emotional symptoms) and higher rate of being admitted to inpatient care might best be considered in the light of the increased emotional problems in the girl group. Quinn & Madhoo [9] also report that girls often are prescribed anti-depressive medication prior the ADHD diagnosis.

The increased level of emotional problems might be seen as a result of impaired everyday functioning due to difficulties related to ADHD. It is possible that treatment for ADHD also will reduce the emotional symptoms, both anxiety and depression, as well as reduce stress if the child with ADHD experiences a higher level of inner control in everyday life situations.

No gender difference was found regarding the time span between first visit and diagnosis. The mean time from first visit to diagnostic discussion was 3 years, albeit with individual variations. However, the girls had more visits at the clinic before they received the ADHD diagnosis. Diagnostics of ADHD rely on clinical experience and the clinician’s expertise regarding gender specific symptoms [13]. Girls self-report more symptoms when getting older [4]. Despite this, ADHD in girls might go undetected if the clinician is not familiar with gender specific presentations of symptoms. Many girls can also be missed if greater emphasis is given to parent- and teacher rating scales compared to youth self-rating scales. Furthermore, requiring symptoms according to diagnostic criteria in at least two contexts can delay correct diagnosis for those girls who only show subtle symptoms in school.

There might also be a gender difference in the self-perception and/or the self-report of ADHD symptoms, which might complicate the diagnostic process. Maybe girls and boys use different words and have different ways to describe the same type of inner feelings and to describe similar symptoms. A girl with ADHD might describe (and experience?) ADHD symptoms as ‘emotional’ symptoms. What a boy with ADHD describes as restlessness might be described by a girl with ADHD as anxiety. As Barkley [4] states, the DSM-5 is lacking some consideration related to the gender differences.

Strength and limitations of the study

The strength of the study is the random selection of cases with girls and age matched boys with ADHD from registers at six different CAP outpatient clinics. The study is retrospective which guarantees that the diagnostic process was not be influenced by the study. A limitation is the limited number of the participants, and the non-standard collection of the original medical record data.

Conclusion

Girls with ADHD seem more often to be referred to CAP due to emotional problems, be older than boys when they first visit the clinic and older when they receive the diagnosis. More visits to CAP were required for girls before the diagnosis was established. The results highlight the need for broader psychiatric investigations including neuropsychiatric symptoms in girls referred for ‘emotional problems’. A broad diagnostic perspective from the first visit at CAP is essential.

Disclosure statement

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

Additional information

Funding

Financial support was given by the Per and Ann-Marie Ahlqvist Foundation (E.B, C.G.) and by the Torsten Söderberg Foundation (C.G).