Relationship of attention-deficit–hyperactivity disorder symptoms, depressive/anxiety symptoms, and life quality in young men

Authors


*Chin-Bin Yeh, MD, Department of Psychiatry, No. 325, Sec 2, Chenggung Road, Neihu, Taipei 114, Taiwan. Email: cyeh@mail.ndmctsgh.edu.tw

Abstract

Aim:  Attention-deficit–hyperactivity disorder (ADHD) continues to be among the most frequently missed of psychiatric diagnoses in adults because its presentation in adulthood so often mimics those of better-known disorders. The aim of the present study was to examine the relationship between ADHD symptoms, depression/anxiety symptoms, and life quality in young men.

Methods:  Nine hundred and twenty-nine draftees into the Taiwanese army completed the Adult ADHD Self-Report Scale (ASRS), the World Health Organization (WHO) Quality of Life–Brief Version, the Epworth Sleepiness Scale, the second edition of the Beck Depression Inventory, and the Beck Anxiety Scale. Based on high ASRS scores, a total of 328 adults (35.3%) were identified as having ADHD: 65 (7.0%) with definite ADHD and 263 (28.3%) with probable ADHD.

Results:  The 328 subjects in the ADHD group had more severe depressive, anxiety symptoms and daytime sleepiness, and had poorer quality of life than the 601 controls (all P < 0.05).

Conclusions:  ADHD should be included in the differential diagnosis for young men presenting with anxiety, depression, daytime sleepiness, and poor quality of life.

ATTENTION-DEFICIT–HYPERACTIVITY DISORDER (ADHD), which affects between 3% and 10% of the school-age population1 and 4% of the general population,2 is a major risk factor for many types of comorbid psychopathology.2–5 Thirty-three percent of childhood patients retain the full ADHD diagnosis into adulthood, and 66% have a partial ADHD diagnosis with moderate persistence of the symptoms of impairment.3

Disorders that co-occur with ADHD have spawned an extensive body of literature.2,6–16 In addition, ADHD itself continues to be mistaken for other disorders,3 especially in adults. ADHD is often accompanied by characteristics not explicitly associated with the current criteria for ADHD as specified in DSM-IV. Although DSM-IV notes that approximately half of all clinic-referred children with ADHD also have oppositional–defiant or conduct disorders (ODD/CD) and also mentions its frequent association with mood disorders, anxiety disorders, learning disorders, and communication disorders, it does not comprehensively describe the clinical presentation of these cases. As a result, most physicians are left to sort out an often bewilderingly complex array of symptoms on their own. In addition, in previous studies, mood and anxiety disorders are less often discussed than ODD, CD, and substance use disorder (SUD) as comorbidities in youth or adults with ADHD.

A cross-sectional study that assessed comorbidity of clinically referred adults with ADHD found current depression in 37%, alcohol abuse or dependence in 33%, and illicit drug abuse or dependence in 22%.17 In another treatment-seeking group, 18% had major depressive disorder, 32% had dysthymic disorder, and 32% had general anxiety disorder.18 The pattern of comorbidity in adults with ADHD was further confirmed in a large family study showing that 87% and 56% had one or two or more psychopathologies, respectively, as compared to 64% and 27% in the control population.2,6 The presence of anxiety and depression during childhood or adolescence, however, did not predict the persistence of ADHD into adulthood.19 Thus, the prevalence of comorbid depressive disorder or anxiety disorder of adults with ADHD remains controversial, although the prevalence of comorbid ODD and CD were consistent in previous studies. In addition, adults with ADHD reported more sleep disturbance20 and poor quality of life.21 Very few studies have focused on daytime sleepiness and the association of severity of ADHD symptoms with the subjective feeling of poor quality of life.

The purpose of the present study was to investigate conditions co-occurring with ADHD in a community-based sample and focus on manifestations of ADHD in young adults most likely to have concurrent conditions. Elucidation of these concurrent characteristics is expected to influence the inclusion of ADHD in the differential diagnosis of childhood and adult psychiatric presentations and increase the accuracy of its identification.

METHODS

Instruments

The instruments included the Chinese version of the World Health Organization (WHO) 18-question Adult ADHD Self-Report Scale (ASRS), the WHO Quality of Life–Brief Version (WHOQOL-BREF), the Epworth Sleepiness Scale (ESS), the second edition of the Beck Depression Inventory (BDI-II), and the Beck Anxiety Scale (BAI).

Chinese ADHD Adult Self-Report Scale

The ASRS is the WHO Composite International Diagnostic Interview (CIDI), which is based on the 18 DSM-IV symptoms of ADHD. Questions in the ASRS have been modified to maximize the questionnaire's face validity. The validity and reliability have been established in previous studies.22 The two-part questionnaire consists of subscales on inattention and hyperactivity/impulsivity, each with nine indications that have persisted for at least 6 months ‘to a degree that is maladaptive and inconsistent with the patient's developmental level’. Scoring is based on a 5-point Likert scale (from 0 for ‘never’ to 4 for ‘very often’).12

The psychometric properties of the Chinese ASRS have been established using large college and army samples,23 and the Chinese ASRS has been used in a previous study examining the association between ADHD and sleep problems in Taiwanese adults.20 The 18-question ASRS Symptom Checklist can be found online at http://www.hcp.med.harvard.edu/ncs/asrs.php

World Health Organization Quality of Life–Brief Version

The WHOQOL-BREF is a standardized self-report assessment tool used to evaluate quality of life in four specific (physical, psychological, social relations, and environment) and two global (overall quality of life and general health) domains on a 5-point scale (1 for ‘not at all satisfied’ to 5 for ‘extremely satisfied’). The Chinese version of the WHOQOL-BREF (TW) has been described in previous studies.24,25 It is scored from 0 to 100 (0, worst quality of life; 100, best). Both the Chinese and English versions of the WHOQOL-BREF have high internal consistency, reliability, and validity in a wide range of studies with different diagnostic populations.24,25

Epworth Sleepiness Scale

The ESS is a self-assessment tool that is used to evaluate the degree of patient daytime somnolence. The respondent completes a self-evaluation of their sleeping habits in eight different situations (sitting and reading; watching TV; sitting inactive in a public place; sitting in a motor vehicle as a passenger for an hour or more; lying down in the afternoon; sitting and talking to someone; sitting quietly after lunch; and sitting in a car at a traffic stop). Patients rate their chance of dozing on a numerical scale from 0 for ‘would never doze’ to 3 for ‘high likelihood of dozing.’ A total score ≥9 indicates that the patient is ‘very sleepy and should seek immediate medical advice’.26 The Chinese version of the ESS has acceptable internal consistency (Cronbach's α = 0.81) and adequate test–retest reliability (correlation coefficient: 0.74).27

Beck Depression Inventory, 2nd edition

The BDI-II is a self-report, 21-item instrument that assesses the existence and severity of the depressive symptoms listed in the DSM-IV; each of its items is scored from 0 for ‘not at all’ to 3 for ‘almost always’. Cut-off score thresholds are adapted to the characteristics of the sample. Total scores of 0–13, 14–19, 20–28, and 29–63 indicate ‘minimal’, ‘mild’, ‘moderate’, and ‘severe’ depression, respectively. The Chinese version of the BDI-II has demonstrated substantial internal consistency, reliability, and stability in a study of Hong Kong adolescents.28

Beck Anxiety Inventory

The BAI is a standardized, 21-item, self-report questionnaire that differentiates anxiety from depression while displaying convergent validity. Items are rated from 0, ‘not at all’, to 3, ‘almost unbearable’. A total score of 14–19 is considered indicative of mild anxiety; 20–28 of moderate anxiety; and 29–63 of severe anxiety. Cut-off score thresholds are adjusted according to the characteristics of the sample. The Chinese version of the BAI has demonstrated high internal consistency (Cronbach's α = 0.95, Guttman split-half coefficient, 0.91) and high convergent validity with Hamilton anxiety scale (Pearson's correlation, 0.72).29

Participants

Between January and July 2005, study subjects were recruited from the pool of Taiwanese men reporting for conscript military duty to three northern Taiwan army bases. Before the implementation of the study, informed oral and written consent was obtained from all participants after the objective and procedure of the study were explained and voluntary participation and confidentiality of data were assured. Data for the present study were from the works added to the routine mental health survey given to all soldiers in conjunction with their routine physical examination. Young men who suffered from any major systemic physical illness, handicap, and/or severe mental disorders were excluded from the conscript military services. Examining physicians had been instructed to exclude study subjects with a history of major somatic illness, schizophrenia, bipolar disorder, major depression, or neurotic disorders, but these routine mental and physical examinations did not reveal any obvious physical or mental problems. Totally, 929 draftees into the Taiwanese army (mean age, 22.27 ± 1.93) were enrolled and filled out questionnaires.

The subjects were placed into either an ADHD or control group on the basis of ASRS inattention and hyperactivity subscores. The inattention subscore was ≥24 in 56 subjects (6.0%), ≥17 and <24 in 240 subjects (25.8%), and <17 in 633 subjects (68.1%). The hyperactivity subscore of the ASRS was ≥24 in 21 subjects (2.3%), ≥17 and <24 in 144 subjects (15.5%), and <17 in 764 subjects (82.2%). ADHD was diagnosed in 328 subjects (35.3%): 65 (7.0%) with inattention or hyperactivity subscore ≥24, and 263 (28.3%) with either inattention or hyperactivity subscore ≥17 and <24. Thus, the remaining 601 were control subjects.

The two groups did not differ significantly in education level, smoking habit, or ethanol drinking habit, but the ADHD group (22.02 ± 1.82 years) was significantly younger than the control group (22.41 ± 1.99 years; P < 0.01).

Other procedures

Individuals at risk for significant psychiatric disorders based on scores for adjustment disorder, major depressive disorder, risk of suicide and so on were referred to psychiatrists. At the time of enrollment in the present study no patients had adjustment disorder, or major depressive disorder, or high risk of suicide.

Data analysis

Independent t-tests for continuous variables and χ2 tests for categorical variables were then performed to compare the two groups. Moreover, analysis of covariance (ANCOVA) was carried out to control for potentially confounding factors and assess the between-group difference in anxiety, depression, quality of life, and ESS. SPSS 13.0 for Windows (SPSS, Chicago, IL, USA) was utilized for all statistical analyses, with significance set at α = 0.05.

RESULTS

Analysis of covariance (ancova) was carried out to control for age. After controlling for the confounding of age, there were significant between-group differences in the BDI-II and BAI, WHOQOL-BREF, and ESS (P < 0.01; Table 1), suggesting that ADHD in adults is associated with more depressive symptoms, anxious symptoms, daytime sleepiness, and impaired quality of life.

Table 1.  Differences in anxiety, depression, sleepiness, and quality of life (n = 929; mean ± SD)
VariableADHD (n = 328)Control (n = 601)P
  1. P < 0.05 indicates statistical significance.

  2. Analysis of covariance (ancova) was carried out to control for age as a confounding factor.

  3. The subjects were placed into either an ADHD or control group on the basis of ASRS inattention and hyperactivity subscores.

  4. ADHD, attention-deficit–hyperactivity disorder; ASRS, Adult ADHD Self-Report Scale; WHOQOL-BREF, World Health Organization Quality of Life-Brief Version.

BDI-II17.53 ± 12.087.83 ± 6.78<0.01
BAI16.36 ± 13.057.57 ± 8.71<0.01
WHOQOL-BREF67.19 ± 15.9880.43 ± 15.48<0.01
Epworth Sleepiness Scale11.08 ± 3.978.83 ± 3.84<0.01

DISCUSSION

Compared with the controls, the present ADHD group had more depressive–anxious symptoms. A recent study in Brazil found that up to 25% of 320 adults clinically referred for treatment of ADHD presented major depressive disorders.4 Other studies also found that major depression is the most common lifetime psychiatric disorder among patients with ADHD.2,30 Between 15% and 35% of children with ADHD also manifest significant anxiety.31 Comorbidity with major depressive disorder was found to exacerbate the impact of ADHD.30 The comorbid anxiety in ADHD subjects may increase their deficit of working memory,32 and impaired the executive functions.33 Most adults with ADHD who are untreated may develop comorbid mental disorders, such as depression or anxiety.34 Also, 23.5% of adults with panic disorder have a history of ADHD.35

Compared with the controls, the ADHD group had poorer quality of life (rated on the WHOQOL-BREF). A recent study measuring the concurrent conditions of adults with undiagnosed ADHD showed that emotional symptoms disrupted work, social life, and fulfillment of family responsibilities, and increased interpersonal difficulties.21 Adults with ADHD had lower socioeconomic status, lower educational level, made more frequent job changes, and had greater level of functional impairment.36 They were prone to unstable relationships, marital problems, and difficulties in family and peer relations.37

We previously found that subjects with ADHD tended to have a variety of current and lifetime sleep problems including inattentiveness (related to increased sleep) and hyperactivity (related to decreased sleep).20 In the present study the ADHD group had a greater daytime sleepiness problem on the Epworth sleepiness scale. A previous study of 84 patients with hypersomnias (mean age 48.45 ± 16.21) and 61 patients with ADHD (mean age 34.98 ± 10.28) found that 37.7% of adults with ADHD had severe excessive sleepiness (ESS ≧ 12). Of the patients with hypersomnias, 18.9% met the criteria for ADHD.38

In the present study, the mean age of the ADHD group was lower. We considered that adults with ADHD might enlist in the army at a younger age because of frustrations in daily living as reported in quality of life surveys, but the two groups did not differ in educational level. This might be due to recruitment of cases from the community rather than from the patient population. Symptoms in the present community-based sample might not be severe enough to interfere significantly with learning, so that subjects could still pursue technological occupations or go to technological rather than academic institutions. In addition, in Taiwan, some military patients (who were diagnosed with adjustment disorder with mixed anxiety or depressed mood/behavior problems or major depressive disorder) were found to have a childhood history of ADHD. This finding may help us understand the relationship between depressive/anxiety symptoms and ADHD symptoms during stress situations. This relationship warrants further study.

To help control for the confounding influences of age and gender, the present subject population consisted entirely of young adult Taiwanese male conscripts into the Taiwanese army. In contrast to previous studies of comorbidity in subjects with ADHD, the present focus was on self-reported psychiatric symptoms rather than clinical diagnosis, and the present control group may have been a more representative age-matched population. Concurrent conditions were identified from self-reports, which may place more emphasis on subjective feelings influenced by diurnal and nocturnal sleep or fatigue problems.

The main limitation of the present study was that the diagnosis of ADHD was not made on the basis of an interview. Instead, we used the ASRS to identify respondents with ADHD. There is a lack of consensus in the psychiatric community on criteria for identifying ADHD in adults, possibly because diagnosis by interview is difficult if there is no childhood history of ADHD. But it is not inconceivable that the results of self-reported questionnaires could help clarify this issue.

The present findings imply that all physicians and mental health professionals should include ADHD, a common but easily missed diagnosis, in the differential diagnosis for adult patients who present symptoms of anxiety, depression, and sleepiness.

ACKNOWLEDGMENTS

This study was supported by the following grants: NSC96-2314-B-016-051-MY2, TSGH-C96-60, and TSGH-C95-55.

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