Psychiatric comorbidity and functional impairment in a clinically referred sample of adults with attention-deficit/hyperactivity disorder (ADHD)

OBJECTIVE: This exploratory study aims to compare lifetime psychiatric axis-I-comorbidity and psychosocial functioning in a clinically referred sample of adult patients with attention-deficit/hyperactivity disorder (ADHD) with a population-based healthy control group and to examine whether patients with ADHD and lifetime comorbid diagnoses differ from patients with pure ADHD in their functional impairment. METHOD: Seventy adult patients with ADHD according to DSM-IV criteria and a gender- as well as age-matched population based control group underwent diagnostic evaluations with clinical interviews for ADHD, DSM-IV disorders and demographic information. RESULTS: The prevalence of psychiatric lifetime comorbidity was 77.1% in patients with ADHD and thus exceeded the rate in the control group, which was 45.7%. Significantly more patients suffered from depressive episodes, substance related disorders and eating disorders. Compared to the control group adults with ADHD were significantly impaired in a variety of psychosocial functions (education, occupational training). Patients with ADHD and lifetime diagnosis of comorbid psychiatric disorders differed from patients with pure ADHD in their psychosocial functioning only in the percentage of unemployed individuals, which was higher in patients with psychiatric comorbidity. CONCLUSION: Adults with ADHD suffer significantly more often from other psychiatric disorders than individuals of the population-based control group and are impaired in several areas of psychosocial functioning. Poor psychosocial outcome is primarily related to ADHD and not to additional psychiatric disorders. Due to the limited number of assessed patients these results need to be confirmed by studies with larger sample size.     

Psychiatric comorbidity associated with DSM-IV ADHD in a nonreferred sample of twins

OBJECTIVE: To test the external validity of the dimensions and subtypes of DSM-IV attention-deficit/hyperactivity disorder (ADHD) by assessing the prevalence of psychiatric comorbidity. METHOD: Eight- to 18-year-old twins with ADHD (n = 105) and without ADHD (n = 95) were recruited through local school districts. Comorbid disorders were assessed by structured diagnostic interviews with the parent and child and by a behavioral rating scale completed by the child's classroom teacher. RESULTS: Symptoms of inattention were associated with lower intelligence and higher levels of depression, whereas symptoms of hyperactivity-impulsivity were associated more strongly with symptoms of oppositional defiant disorder (ODD) and conduct disorder (CD). All DSM-IV subtypes were associated with higher rates of ODD and CD in comparison with controls, and the combined type was associated with more disruptive behavior disorder symptoms than the other 2 subtypes. The combined type and predominantly inattentive type were associated with more symptoms of depression than controls or the predominantly hyperactive-impulsive type. CONCLUSIONS: These results provide support for the discriminant validity of the dimensions and subtypes of DSM-IV ADHD and suggest that clinicians should carefully screen for comorbid disorders as part of a comprehensive assessment of ADHD.     

ADHD and comorbid depression

Attention-deficit/hyperactivity disorder (ADHD) is prevalent, chronic, and often comorbid with other disorders. This article reviews the literature on ADHD and comorbid major depressive disorder from childhood through adolescence and adulthood. We also report findings from a study we conducted that examined the prevalence of ADHD and comorbid major depression in adults. Diagnostic history data were analyzed in 524 adults (308 men; 216 women), 383 of whom had a diagnosis of ADHD. Adults with ADHD were more likely to have current major depression than adults without ADHD. Adults with the combined subtype of ADHD were more likely to have past and current major depression than those with the inattentive and hyperactive impulsive subtypes. Men and women with ADHD were more likely to have current major depression than men and women without ADHD, but women in the inattentive and combined subtype groups were more likely to have had past major depression than women in the hyperactive impulsive subtype group. Implications for diagnosis and treatment are discussed.     

成人注意缺陷多动障碍临床特点的初步分析

目的初步分析我国成人注意缺陷多动障碍(ADHD)患者的症状特点、共病及社会功能情况。方法对6～16岁曾就诊于我院的88例符合美国精神障碍诊断与统计手册第4版(DSM-IV)的ADHD患儿在≥18岁时采用DSM-IV配套的定式会谈工具进行再评估,以满足成人ADHD诊断标准者59例为研究组,对照组为29例不满足ADHD诊断标准且GAF评分70分者,比较两组临床特点的不同。结果成人ADHD临床分型以ADHD-I为主,占86.4%(51/59);"经常"出现的症状依次是:"组织事情有困难"(98.3%)、"逃避需要大量持续用脑的任务"(96.6%)、"不能注意细节"(94.9%)、"很难遵从指令且完不成工作"(96.6%)、"注意持续时间短"(88.1%)和"因外界刺激而分心"(72.9%)。成人ADHD中共患任何一种DSM-Ⅳ轴Ⅰ或轴Ⅱ障碍者66.1%(39/59),其中39.0%(23/59)至少共患一种轴Ⅰ精神障碍,49.2%(29/59)至少共患一种轴Ⅱ障碍。成人ADHD组功能大体评定量表得分明显低于对照组(t=12.96,P0.001),74.6%(44/59)出现轻或中度社会功能损害。结论成人ADHD的临床表现以注意缺陷型为主,共患其他精神障碍及人格障碍较多,总体社会功能相对较差。     

Assessing adult attention-deficit/hyperactivity disorder: a Turkish version of the current symptoms scale

We report normative data for a Turkish translation of the Current Symptoms Scale (CSS), a screening measure of adult attention-deficit/hyperactivity disorder (ADHD). The CSS yields 3 scores reflecting diagnostic criteria for: (1) ADHD, predominantly hyperactive-impulsive type; (2) ADHD, predominantly inattentive type, and (3) ADHD, combined type. For comparison purposes, we also present normative data from a community sample in the United States. Central tendency, variability, and correlation patterns among Turkish subjects (n=181) were similar to patterns demonstrated by respondents in the United States (n=114). Mann-Whitney U tests revealed that the Turkish and US groups did not differ significantly on the subscales assessing inattentive and hyperactive-impulsive symptoms. Both versions demonstrated acceptable levels of internal consistency (Cronbach's alpha coefficients ranged from 0.65 to 0.78 for the Turkish version, and from 0.63 to 0.75 for the English version). The Turkish version of the CSS demonstrated excellent test- retest reliability. The test-retest coefficient for the CSS (total score) was 0.82. The inattentive type subscale also showed good test-retest reliability, with r=0.78. The test-retest coefficient for the hyperactive-impulsive type subscale was appreciably lower, with r=0.68; albeit, in the acceptable range. Investigators have determined that many adults, initially diagnosed with ADHD as children, continue to demonstrate clinically significant symptoms. Since adult ADHD is associated with a number of comorbid psychiatric conditions and treatment of the underlying attentional, executive, and impulse control difficulties is associated with a reduction in comorbid psychiatric symptoms, the routine screening for adult ADHD in psychiatric and mental health settings may be warranted.     

Can adults with attention-deficit/hyperactivity disorder be distinguished from those with comorbid bipolar disorder? Findings from a sample of clinically referred adults.

BACKGROUND: Despite data describing the overlap of attention deficit hyperactivity disorder (ADHD) and bipolar disorder (BPD) in youth, little is known about adults with these co-occurring disorders. We now evaluate the clinical characteristics of referred adults with (n = 24) and without BPD (n = 27). METHODS: Referred adults to clinical trials of ADHD were evaluated by psychiatric evaluation using DSM-IV criteria. Structured psychiatric interviews were used to systematically assess adult and childhood disorders. RESULTS: The vast majority of patients with ADHD plus BPD had bipolar II disorder (88%). Adults with ADHD plus BPD had higher rates of the combined subtype of ADHD compared to ADHD without BPD (chi(2) = 8.7, p =.003), a greater number of DSM-IV ADHD symptoms (14.8 +/- 2.9 and 11.4 +/- 4.0; t = -3.4, p <.01), more attentional symptoms of ADHD (8.1 +/- 1.4 and 6.8 +/- 2.1; t = -2.5, p <.02; trend), poorer global functioning (47 +/- 5.9 and 52 +/- 7.4, t = 2.6, p <.02; trend), and additional comorbid psychiatric disorders (3.7 +/- 2.5 and 2.0 +/- 1.9; t = -2.9, p <.01). CONCLUSIONS: These results suggest that adults with ADHD plus BPD have prototypic symptoms of both disorders, suggesting that both disorders are present and are distinguishable clinically.     

Biological and psychosocial environmental risk factors influence symptom severity and psychiatric comorbidity in children with ADHD

Attention-deficit/hyperactivity disorder (ADHD) is a genetically as well as environmentally determined disorder with a high rate of psychiatric comorbidity. In this study, non-genetic biological and psychosocial risk factors for ADHD symptom severity and comorbid disorders were assessed in 275 children with ADHD, aged 5–13 years, mean age 9.7 (SD 1.9). Pre-/perinatal biological and lifetime psychosocial risk factors as well as data on parental ADHD were obtained. A different pattern of risk factors emerged for inattentive and hyperactive-impulsive ADHD symptoms. Inattentive symptoms were strongly influenced by psychosocial risk factors, whereas for hyperactive-impulsive symptoms, predominantly biological risk factors emerged. Hyperactive-impulsive symptoms also were a strong risk factor for comorbid oppositional defiant (ODD) and conduct disorder (CD). Smoking during pregnancy was a risk factor for comorbid CD but not ODD and further differential risk factors were observed for ODD and CD. Comorbid anxiety disorder (AnxD) was not related to ADHD symptoms and additional biological and psychosocial risk factors were observed. This study adds to the body of evidence that non-genetic biological and psychosocial risk factors have an impact on ADHD symptom severity and differentially influence comorbid disorders in ADHD. The findings are relevant to the prevention and treatment of ADHD with or without comorbid disorders.     

Differential patterns of executive function in children with attention-deficit hyperactivity disorder according to gender and subtype

The present investigation examined differential patterns in executive functions of children with attention-deficit hyperactivity disorder (ADHD; no diagnosed comorbid disorders) according to subtype and gender, and identified instrumentation sensitive to executive function in children aged 6 to 12 years with ADHD. Data were obtained from 94 children diagnosed with ADHD (predominantly inattentive, n = 32, ADHD combined, n = 62), and from 28 controls. Participants with ADHD, who were unmedicated at the time of testing, were administered five tests of executive function (the Wisconsin Card Sorting Test, the Stroop Color-Word Test, the Matching Familiar Figures Test, the Trail Making Test, and the Tower of London). A two-way multivariate analysis of covariance with age as the covariate and subtype and gender as the independent variables was conducted on all of the tests administered. While children with ADHD predominantly inattentive and those with ADHD combined differed from controls, it was only the latter subtype that differed significantly in perseveration and response inhibition. The absence of diagnosed comorbidity in the children with ADHD at the time of test administration demonstrates that the impairments in executive function are clearly located in ADHD, particularly in the ADHD combined subtype, thus providing support for Barkley's proposed unifying theory of ADHD.     

Family adversity in DSM-IV ADHD combined and inattentive subtypes and associated disruptive behavior problems

OBJECTIVE: This study evaluated the relationship between a family adversity index and DSM-IV attention-deficit/hyperactivity disorder (ADHD) subtypes and associated behavior problems. The relationship of family adversity to symptoms and subtypes of ADHD was examined. METHOD: Parents and 206 children aged 7-13 completed diagnostic interviews and rating scales about socioeconomic status, parental lifetime psychiatric disorders, marital conflict, and stressful life events. RESULTS: Children with ADHD combined type experienced more risk factors than community controls (p = .002) or children with ADHD predominantly inattentive type (p = .02). The families of children with ADHD combined type described more risk factors associated with family adversity than the families of children with ADHD inattentive type and the control group. Parent-rated symptoms of child inattention/disorganization were related uniquely to the adversity index score independently of conduct disorder symptoms. Children's perceptions of marital conflict were independently related to inattention and hyperactivity behaviors as rated by parents and teachers after control of all other risk factors. Oppositional defiant symptoms were independently related to marital conflict and maternal psychopathology, whereas conduct disorder symptoms were uniquely related to low socioeconomic status and maternal psychopathology. CONCLUSIONS: Family adversity is related to ADHD combined type in children and may be related specifically to ADHD symptoms in addition to conduct disorder symptoms.     

Family factors and sampling approach differentially influence attention deficit/hyperactivity disorder subtypes

A widely used statistical method to test for genetic association is the transmission disequilibrium test (TDT) using two parent-proband trios. West et al(1) have presented evidence from clinically ascertained ADHD families that children from trios were less likely to have DSM-IV combined subtype ADHD and conduct disorder. They suggest that the exclusion of parent-proband duos could reduce the power of the TDT and similar tests to detect susceptibility genes for this subtype of ADHD. We sought to test this hypothesis in a population-based sample of twin families, while controlling for the effects of other proband and family characteristics in a multivariant logistic regression framework using both latent class and DSM-IV ADHD subtype definitions. For both latent class and DSM-IV defined combined and inattentive ADHD, sex of the proband and comorbid conduct disorder or oppositional defiant disorder, significantly predicted diagnosis. For latent class and DSM-IV defined combined subtype, younger age also significantly predicted ADHD subtype. Latent class and DSM-IV defined combined subtype ADHD with comorbid conduct disorder was significantly less common in children from trios while conduct disorder without ADHD did not differ in frequency between families with zero, one or two participating parents.     

Behavioral and genetic evidence for a novel animal model of Attention-Deficit/Hyperactivity Disorder Predominantly Inattentive Subtype

Background  

According to DSM-IV there are three subtypes of Attention-Deficit/Hyperactivity Disorder, namely: ADHD predominantly inattentive type (ADHD-PI), ADHD predominantly Hyperactive-Impulsive Type (ADHD-HI), and ADHD combined type (ADHD-C). These subtypes may represent distinct neurobehavioral disorders of childhood onset with separate etiologies. The diagnosis of ADHD is behaviorally based; therefore, investigations into its possible etiologies should be based in behavior. Animal models of ADHD demonstrate construct validity when they accurately reproduce elements of the etiology, biochemistry, symptoms, and treatment of the disorder. Spontaneously hypertensive rats (SHR) fulfill many of the validation criteria and compare well with clinical cases of ADHD-C. The present study describes a novel rat model of the predominantly inattentive subtype (ADHD-PI).     

Effect of subtype and psychiatric comorbidities on methylphenidate treatment in adults with attention-deficit hyperactivity disorder

The present study was intended to examine the efficacy of immediate-release methylphenidate (MPH IR) in the treatment of adults with attention-deficit hyperactivity disorder (ADHD) under consideration of subtype according to DSM-IV criteria and psychiatric comorbidity. After baseline assessment over 3 weeks, 47 patients aged 18-59 years with combined ADHD (ADHD-C) (n=27) and predominantly inattentive ADHD (ADHD-I; n=20) were treated in an open, uncontrolled design with an average dose of 0.5 mg MPH IR per kg over 7 weeks. Thirty-nine patients finished the study. The two groups did not differ in response to treatment with regard to ADHD symptoms (very good to good outcome in ADHD-C 73.9%, in ADHD-I 66.7%) or cognitive measures (sustained attention, information processing speed, divided attention). However, ADHD patients with psychiatric comorbidities had significantly worse outcome: total ADHS scores on the T2 Brown Attention Deficit Disorder Scales (BADDS) were 66.2+/-15.5 with psychiatric comorbidity and 51.7+/-13.7 without (P=0.04), despite significantly higher doses of MPH IR (0.56+/-0.17 mg/kg vs 0.46+/-0.13 mg/kg; P=0.004). This effect was mainly seen in the patients with clinically significant depressive symptoms (Beck Depression Inventory > or =18), who clearly benefited less from treatment (total T2 BADDS scores with depressive symptoms 70.7+/-15.9 and without depressive symptoms 48.1+/-21.2; P=0.001).     

Sleep problems in children with attention-deficit/hyperactivity disorder: impact of subtype, comorbidity, and stimulant medication.

OBJECTIVE: To determine the relationship of sleep problems to attention-deficit/hyperactivity disorder (ADHD), diagnostic subtype, comorbid disorders, and the effects of stimulant treatment. METHOD: On the basis of clinical diagnostic interviews, children aged 6 to 12 years were assigned to 4 groups: unmedicated ADHD (n = 79), medicated ADHD (n = 22), clinical comparison (n = 35), and healthy nonclinical comparison (n = 36). These groups were compared on 2 sleep questionnaires completed by the parents that assessed current sleep problems and factors associated with sleep difficulties (i.e., sleep routines, sleep practices, child and family sleep history). RESULTS: Factor analysis revealed 3 sleep problem categories: dyssomnias, parasomnias, and sleep-related involuntary movements. Linear regression analyses showed that (1) dyssomnias were related to confounding factors (i.e., comorbid oppositional defiant disorder and stimulant medication) rather than ADHD; (2) parasomnias were similar in clinical and nonclinical children; and (3) the DSM-IV combined subtype of ADHD was associated with sleep-related involuntary movements. However, sleep-related involuntary movements were more highly associated with separation anxiety. CONCLUSIONS: The results suggest that the relationship between sleep problems and ADHD is complex and depends on the type of sleep problem assessed as well as confounding factors such as comorbid clinical disorders and treatment with stimulant medication.     

ADHD symptoms and subtypes: relationship between childhood and adolescent symptoms

OBJECTIVE: To study attention-deficit/hyperactivity disorder (ADHD) symptoms and DSM-IV subtypes in childhood and adolescence. METHOD: A total of 457 adolescents ages 16 to 18 years from the Northern Finland Birth Cohort 1986 participated in an epidemiological survey for ADHD. After assessment with a diagnostic interview those with current or childhood ADHD were classified using DSM-IV criteria. Childhood diagnosis of ADHD was set according to retrospective recall. The characteristics and relationships in ADHD symptomatology in childhood and adolescence were studied in relation to behavioral problems and parental history of attentional problems. RESULTS: ADHD was reported more commonly in childhood than in adolescence and variations in subtype classification occurred. Those with childhood and adolescent diagnosis had endorsed specific inattentive symptoms more commonly, had greater comorbid major depression and/or oppositional defiant disorder, and had fathers with more reported attentional problems than those with only childhood diagnosis. In childhood, ADHD subtypes differed along symptom severity, but by adolescence these differences were no longer significant. CONCLUSIONS: The persistence of ADHD from childhood to adolescence may be common. Specific inattentive symptoms, certain psychiatric comorbidity, and family history of attention problems (fathers specifically) contribute to the risk of persistent ADHD. ADHD subtype differences reflect symptom severity differences in childhood that are negligible by adolescence.     

Does actigraphy differentiate ADHD subtypes in a clinical research setting?

OBJECTIVE: To compare subtypes of attention-deficit/hyperactivity disorder (ADHD) (predominantly inattentive and combined types) and a comparison group on an objective measure of activity level (actigraphy). METHOD: Actigraphs were worn by 64 children (49 boys, 15 girls) during a full-day clinical diagnostic assessment; 20 subjects had a diagnosis of ADHD predominantly inattentive type, 22 had ADHD combined type, and 22 were non-ADHD controls. Mean actigraph scores were calculated for two 2-hour intervals, comprising, respectively, a psychometric evaluation in the morning and the completion of a speech and language assessment and research measures in the afternoon. RESULTS: There were no significant group differences in activity level in the morning session. During the afternoon session, children with ADHD were significantly more active than controls, but there were no differences between ADHD subtypes. CONCLUSIONS: These data partially support specifications in the DSM-IV regarding hyperactivity in ADHD; however, they also indicate that situational and/or temporal factors may affect the degree to which hyperactivity is expressed. Furthermore, the findings contradict specifications in the DSM-IV that suggest that children with ADHD combined type should be more hyperactive than children with ADHD predominantly inattentive type.     

Neuropsychological assessment of attention in adults with different subtypes of attention-deficit/hyperactivity disorder

Summary There is only little information about varying attention functions of adults with different DSM-IV subtypes of attention-deficit/hyperactivity disorder (ADHD). In the present study groups of adult patients with ADHD – predominantly inattentive type, ADHD – predominantly hyperactive-impulsive type or ADHD – combined type and three healthy control groups were compared regarding multiple components of attention. Assessment of attention was performed using a computerized neuropsychological test battery for attentional functions. In comparison with healthy subjects, the three patient groups displayed impairments of vigilance, selective attention, divided attention, and flexibility. These impairments of attention of ADHD subgroups were primarily observed with regard to reaction time. With regard to tonic and phasic alertness no differences between patient and control groups could be found. Comparison between ADHD subgroups revealed that DSM-IV subtypes of ADHD differ in measures of divided attention, selective attention and flexibility. Differences between ADHD subgroups were primarily observed with regard to task accuracy. The results suggest that while distinct profiles of attentional functioning were observed between adult patients with ADHD and healthy adults indicating gross disturbances of various attention functions in patients with ADHD, differences between ADHD subgroups were only weak. Correspondence: Oliver Tucha, School of Psychology, University of Plymouth, Drake Circus, Plymouth, Devon PL4 8AA, UK     

Instability of the DSM-IV Subtypes of ADHD from preschool through elementary school

CONTEXT: The DSM-IV definition of attention-deficit/hyperactivity disorder (ADHD) distinguished 3 subtypes that had not been extensively studied. OBJECTIVE: To determine whether the ADHD subtypes are stable enough over time to be valid. DESIGN: Longitudinal study with a greater-than 89% retention rate in 7 assessments over 8 years. SETTING: Outpatient clinics. PARTICIPANTS: Volunteer sample of 118 4- to 6-year-olds who met DSM-IV criteria for ADHD, including impairment in 2 settings in at least 1 assessment. MAIN OUTCOME MEASURE: Meeting DSM-IV criteria for the subtypes of ADHD during years 2 through 8. RESULTS: The number of children who met criteria for ADHD declined over time, but most persisted. Children who met criteria for the combined subtype (CT, n = 83) met criteria for ADHD in more subsequent assessments than children in the predominantly hyperactive-impulsive subtype (HT, n = 23). Thirty-one (37%) of 83 CT children and 6 (50%) of 12 children in the predominantly inattentive subtype (IT) met criteria for a different subtype at least twice in the next 6 assessments. Children of the HT subtype were even more likely to shift to a different subtype over time, with HT children who persisted in ADHD mostly shifting to CT in later assessments. The subtypes exhibited consistently different mean levels of hyperactive-impulsive symptoms during years 2 through 8 that corresponded with their initial subtype classifications, but initial subtype differences in inattention symptoms diminished in later years. CONCLUSIONS: In younger children, the CT and IT may be stable enough to segregate groups for research, but they seem too unstable for use in the clinical assessment of individual children. Children rarely remain in the HT classification over time; rather, they sometimes desist from ADHD but mostly shift to CT in later years. Using continuous ratings of hyperactivity-impulsivity symptoms as a diagnostic qualifier should be considered as an alternative to classifying nominal subtypes of ADHD in DSM-V.     

The validity of the DSM-IV subtypes of attention-deficit/hyperactivity disorder

OBJECTIVE: To examine the validity of the three subtypes of ADHD defined by DSM-IV. METHOD: Studies published in English were identified through searches of literature databases. RESULTS: Estimates of the prevalence of ADHD have increased as a result of the introduction of DSM-IV criteria. Factor analytical and genetic studies provide some support for the validity of the distinction between the three subtypes. However, diagnosis of the combined subtype seems more reliable than the other two subtypes, although reliability is largely unknown for the latter. The hyperactive-impulsive subtype, the least common, differs from the other two subtypes in age distribution, association with other factors and neuropsychological parameters. Almost all treatment trials are based on participants with the combined type. CONCLUSION: Data supporting the validity of the inattentive and hyperactive-impulsive subtypes of ADHD a decade after the publication of DSM-IV are still scarce. Given that inattention is the hypothesized core ADHD symptom, it remains to be demonstrated that hyperactive-impulsive children who are not inattentive have the same condition. One of the main research deficits refers to data on treatment of the inattentive and hyperactive-impulsive subtypes.     

Characteristics of adults with attention-deficit/hyperactivity disorder and past conduct disorder

Objective: DSM‐IV Attention‐deficit/hyperactivity disorder (ADHD) comorbid with DSM‐IV conduct disorder (CD) in childhood/adolescence has been proposed as a ‘distinct subtype’. The present study investigated subsequent psychopathological characteristics of this proposed subtype in adults. Method: Questionnaires were completed by 71 adults (mean age 29.6 years) with ADHD and their informants. Results: The 39 subjects with a history of past CD, when compared with the remaining subjects, were associated with significantly increased ratings of aspects of ADHD‐related impulsivity, with features of all three DSM‐IV ‘Clusters’ of personality disorders (PDs) (in particular of ‘Cluster B’ PDs) and with other psychopathology. Also, there were significant correlations between the number of endorsed past CD criteria and various self‐ratings of psychopathology. Conclusion: The results indicate the psychopathological characteristics of adults with a history of the proposed ‘ADHD with CD’ subtype. The findings are relevant to future studies of ADHD subtypes in adults.     

Psychiatric comorbidity in adult attention deficit hyperactivity disorder: findings from multiplex families

OBJECTIVE: Patterns of psychiatric comorbidity were assessed in adults with and without attention deficit hyperactivity disorder (ADHD) identified through a genetic study of families containing multiple children with ADHD. METHOD: Lifetime ADHD and comorbid psychopathology were assessed in 435 parents of children with ADHD. Rates and mean ages at onset of comorbid psychopathology were compared in parents with lifetime ADHD, parents with persistent ADHD, and those without ADHD. Age-adjusted rates of comorbidity were compared with Kaplan-Meier survival curves. Logistic regression was used to assess additional risk factors for conditions more frequent in ADHD subjects. RESULTS: The parents with ADHD were significantly more likely to be unskilled workers and less likely to have a college degree. ADHD subjects had more lifetime psychopathology; 87% had at least one and 56% had at least two other psychiatric disorders, compared with 64% and 27%, respectively, in non-ADHD subjects. ADHD was associated with greater disruptive behavior, substance use, and mood and anxiety disorders and with earlier onset of major depression, dysthymia, oppositional defiant disorder, and conduct disorder. Group differences based on Kaplan-Meier age-corrected risks were consistent with those for raw frequency distributions. Male sex added risk for disruptive behavior disorders. Female sex and oppositional defiant disorder contributed to risk for depression and anxiety. ADHD was not a significant risk factor for substance use disorders when male sex, disruptive behavior disorders, and socioeconomic status were controlled. CONCLUSIONS: Adult ADHD is associated with significant lifetime psychiatric comorbidity that is not explained by clinical referral bias.