Attention-deficit hyperactivity disorder with bipolar disorder: a familial subtype?

Current concepts on the neurobiology of Attention-Deficit/Hyperactivity Disorder

Attention-Deficit/Hyperactivity Disorder (ADHD) is an early onset, clinically heterogeneous disorder of inattention, hyperactivity, and impulsivity. In contrast to the widespread acceptance of ADHD as a childhood diagnosis, Its prevalence In adults and its implications for clinical practice remain a source of controversy. Throughout the lifecycle, a key clinical feature observed in ADHD patients is comorbidity with Conduct Depressive, Bipolar, and Anxiety disorders. Family studies consistently support the assertion that ADHD runs in families. Heritability data from twin studies of ADHD attribute about 80 percent of the etiology of ADHD to genetic factors. Adoption studies of ADHD also implicate genes in its etiology. Molecular genetic data are bolstered by considerations suggesting that DRD4 and DAT genes may be relevant for ADHD. Independently of genes, prenatal exposure to nicotine and psychosocial adversity have also been identified as risk factors for ADHD. Structural and functional imaging studies consistently implicate catecholamine-rich fronto-subcortical systems in the pathophysiology of ADHD. The effectiveness of stimulants, along with animal models of hyperactivity, point to catecholamine disruption as at least one source of ADHD brain dysfunction. Although not entirely sufficient, changes in dopaminergic and noradrenergic function appear necessary for the clinical efficacy of pharmacological treatments for ADHD, providing support for the hypothesis that alteration of monoaminergic transmission in critical brain regions may be the basis for therapeutic action in ADHD.

The validity of analyses testing the etiology of comorbidity between two disorders: a review of family studies

BACKGROUND

Knowledge regarding the causes of comorbidity between two disorders has a significant impact on research regarding the classification, treatment, and etiology of the disorders. Two main analytic methods have been used to test alternative explanations for the causes of comorbidity in family studies: biometric model fitting and family prevalence analyses. Unfortunately, the conclusions of family studies using these two methods have been conflicting. In the present study, we examined the validity of family prevalence analyses in testing alternative comorbidity models.

METHOD

We reviewed 42 family studies that used family prevalence analyses to test three comorbidity models: the alternate forms model, the correlated liabilities model, or the three independent disorders model. We conducted the analyses used in these studies on datasets simulated under the assumptions of 13 alternative comorbidity models including the three models tested most often in the literature.

RESULTS

Results suggest that some analyses may be valid tests of the alternate forms model (i.e., two disorders are alternate manifestations of a single liability), but that none of the analyses are valid tests of the correlated liabilities model (i.e., a significant correlation between the risk factors for the two disorders) or the three independent disorders model (i.e., the comorbid disorder is a third, independent disorder).

CONCLUSION

Family studies using family prevalence analyses may have made incorrect conclusions regarding the etiology of comorbidity between disorders.

Does parental ADHD bias maternal reports of ADHD symptoms in children?

Within families, co-occurring attention-deficit/hyperactivity disorder (ADHD) in parents and children may be common. The authors evaluated the hypothesis that parental ADHD may lead to a reporting bias of ADHD symptoms in offspring. They combined 2 family case-controlled studies of ADHD using structured interviews. They compared rates of maternal reported ADHD symptoms among 3 groups of ADHD children: no parental ADHD (n = 231), mother with ADHD (n = 63), and father with ADHD (n = 57). With the exception of 1 symptom, the rates of reporting between groups did not differ. There was no evidence that the discrepancy between maternal reports and self-reports of symptoms differed by parental ADHD. Results were similar across child gender or referral status. These results do not support the notion that parental ADHD affects maternal reports of offspring ADHD.

Parsing the comorbidity between bipolar disorder and anxiety disorders: a familial risk analysis

BACKGROUND

A growing literature suggests that anxiety disorders (ANX) co-occur with bipolar disorder (BPD), but the nature of this overlap is unknown. Thus, we investigated the familial association between BPD and ANX among the first-degree relatives of children with BPD with and without comorbid ANX.

METHODS

We compared relatives of four proband groups defined by the presence or absence of BPD and ANX in the proband: (1) BPD + ANX (n = 23 probands, 74 relatives), (2) BPD without ANX (n = 11 probands, 38 relatives), (3) ANX without BPD (n = 48 probands, 167 relatives), and (4) controls without BPD or ANX (n = 118 probands, 385 relatives). All subjects were evaluated with structured diagnostic interviews. Diagnoses of relatives were made blind to the diagnoses of probands.

RESULTS

The results show high rates of both BPD and ANX in relatives of children with BPD + ANX. Moreover, BPD and ANX cosegregated among the relatives of children with BPD + ANX. Although relatives of both ANX proband groups (with and without BPD) had high rates of ANX, and relatives of both BPD proband groups (with and without ANX) had high rates of BPD, the combined condition BPD + ANX was the predominant form of BPD among relatives of probands with BPD + ANX.

CONCLUSIONS

These family-genetic findings suggest that the comorbid condition BPD+ANX may be a distinct clinical entity. More work is needed to evaluate whether the presence of comorbid ANX may be a marker of very early onset BPD.

Development and natural history of mood disorders

To expand and accelerate research on mood disorders, the National Institute of Mental Health (NIMH) developed a project to formulate a strategic research plan for mood disorder research. One of the areas selected for review concerns the development and natural history of these disorders. The NIMH convened a multidisciplinary Workgroup of scientists to review the field and the NIMH portfolio and to generate specific recommendations. To encourage a balanced and creative set of proposals, experts were included within and outside this area of research, as well as public stakeholders. The Workgroup identified the need for expanded knowledge of mood disorders in children and adolescents, noting important gaps in understanding the onset, course, and recurrence of early-onset unipolar and bipolar disorder. Recommendations included the need for a multidisciplinary research initiative on the pathogenesis of unipolar depression encompassing genetic and environmental risk and protective factors. Specifically, we encourage the NIMH to convene a panel of experts and advocates to review the findings concerning children at high risk for unipolar depression. Joint analyses of existing data sets should examine specific risk factors to refine models of pathogenesis in preparation for the next era of multidisciplinary research. Other priority areas include the need to assess the long-term impact of successful treatment of juvenile depression and known precursors of depression, in particular, childhood anxiety disorders. Expanded knowledge of pediatric-onset bipolar disorder was identified as a particularly pressing issue because of the severity of the disorder, the controversies surrounding its diagnosis and treatment, and the possibility that widespread use of psychotropic medications in vulnerable children may precipitate the condition. The Workgroup recommends that the NIMH establish a collaborative multisite multidisciplinary Network of Research Programs on Pediatric-Onset Bipolar Disorder to achieve a better understanding of its causes, course, treatment, and prevention. The NIMH should develop a capacity-building plan to ensure the availability of trained investigators in the child and adolescent field. Mood disorders are among the most prevalent, recurrent, and disabling of all illnesses. They are often disorders of early onset. Although the NIMH has made important strides in mood disorders research, more data, beginning with at-risk infants, children, and adolescents, are needed concerning the etiology and developmental course of these disorders. A diverse program of multidisciplinary research is recommended to reduce the burden on children and families affected with these conditions.

Characterization of children of bipolar parents by parent report CBCL

In past research the Child Behavior Checklist (CBCL) has differentiated among various diagnostic categories for children and adolescents. However, research has not been conducted on whether the CBCL differentiates among diagnostic categories for children at high risk for development of psychopathology. This study compares four diagnostic groups [bipolar disorder (BD), attention/deficit-hyperactivity disorder (ADHD), Depressed/Anxious and No Diagnosis] within a cohort of 58 children of bipolar parents to determine whether their CBCL scores will replicate the scores of children not at high risk for bipolar disorder. The cohort of children of bipolar parents received elevated scores on the CBCL scales in comparison with non-clinical populations. In addition, the CBCL distinguished between children of bipolar parents with and without clinical disorders. Finally the BD group differed from the ADHD group only on the Aggressive Behaviors, Withdrawn and Anxious/Depressed subscales of the CBCL. Therefore the CBCL did not discriminate between the BD and ADHD groups as it had in previous studies of children with BD and unspecified family history. It is possible that this discrepancy is due to a group of children of bipolar parents with ADHD who are currently prodromal for bipolar disorder and therefore received higher scores on the CBCL based on prodromal symptomatology. A longitudinal follow-up of this cohort is necessary to ascertain whether this is the case.

Severity of bipolarity in hospitalized manic adolescents with history of stimulant or antidepressant treatment

BACKGROUND

Childhood bipolarity (BP) and ADHD frequently co-occur, these children often receive stimulants.

METHOD

We retrospectively evaluated 80 adolescents hospitalized with BP, manic or mixed, assessed severity of hospital course, and compared groups according to current/past stimulant or antidepressant treatment.

RESULTS

Lifetime ADHD rate was 49%; 35% of patients had exposure to stimulants and 44% to antidepressants. Stimulant-exposed patients were younger than non-exposed (mean+/-S.D.=13.7+/-2 vs. 15.1+/-2 years, Z=-3.1, P=0.002). Only stimulant exposure was associated with worse hospitalization course (MANCOVA, Wilks' Lambda=0.87, F=3.4; df=70; P=0.02).

CONCLUSION

Stimulant-exposed BP-adolescents may have more severe illness course not fully explained by ADHD comorbidity.

LIMITATIONS

Retrospective methodology and lack of structured interviewing make it difficult to quantify exposure to stimulants and antidepressants.

Childhood mania, attention deficit hyperactivity disorder and conduct disorder: a critical review of diagnostic dilemmas

OBJECTIVES

Significant debate exists on whether early onset bipolar disorder is mistakenly attributed to attention deficit hyperactivity disorder (ADHD) or conduct disorder (CD), or whether ADHD and CD are frequently misdiagnosed as mania. We review the literature on the extent to which these disorders can be reliably differentiated, and describe the diagnostic confusion that may be the result of features common to both classes of disorders.

METHODS

The review focuses on research studies that have examined whether overlapping symptoms of bipolar disorder, ADHD, and CD contribute to misdiagnosis of the two classes of disorders, the prevalence of early onset bipolar disorder with comorbid ADHD or CD, and theories regarding the origins of this comorbidity.

RESULTS

Reliable and accurate diagnoses can be made despite the symptom overlap of bipolar disorder with ADHD and CD. Children with bipolar disorder and ADHD may have a distinct familial subtype of bipolar disorder. Some findings suggest that manic symptoms may represent 'noise' that indicates the general severity of psychopathology in a child or adolescent.

CONCLUSIONS

Further prospective studies may confirm whether early onset bipolarity can be successfully differentiated from ADHD or CD, whether all three types of disorders can be recognized in comorbid cases, or whether comorbid cases represent a distinct subtype of bipolar disorder.

Familial links between attention deficit hyperactivity disorder, conduct disorder, and bipolar disorder

Although family, twin, and adoption studies indicate that attention deficit hyperactivity disorder (ADHD) is a familial condition with a robust genetic component, molecular genetic studies of candidate genes have produced inconsistent findings. One of the challenges to elucidating the genetic architecture of ADHD is its potential genetic heterogeneity. Therefore, efforts are needed to identify etiologically homogeneous subgroups of subjects with ADHD for use in genetic studies. The current article reviews evidence suggesting that parsing ADHD subjects based on comorbidity with conduct and bipolar disorders may yield familial subtypes that are suitable for genetic analyses.

Genetics of early onset bipolar affective disorder: are we making progress?

Though considerable progress has been made in understanding the molecular genetics of bipolar affective dis order, few studies are currently focusing on the genetics of prepubertal or early adolescent onset illness. A variety of studies of the phenomenology, imaging and comorbidity of early onset bipolarity find significant differences from late onset illness. These studies raise the notion that early onset cases may represent a distinct genetic form or forms of manic-depressive illness.

Relationship between current quality of life and family of origin dynamics for college students with Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

This study examines the relationship between current quality of life, family of origin relationship dynamics, and the presence of Attention-Deficit/Hyperactivity Disorder (ADHD) in college students.

METHOD

Participants were 37 ADHD undergraduate college students and 59 non-ADHD undergraduate students. Participants completed a background information questionnaire, Quality of Life Questionnaire, Family Environment Scale, and the Family Adaption and Cohesion Scale II.

RESULTS

In comparison to the control group, the ADHD group reported lower quality of life. The ADHD and non-ADHD groups did not differ significantly in reported family of origin relationship dynamics. Family of origin dynamics were highly predictive of current overall quality of life for the ADHD group, but less so for the non-ADHD group.

CONCLUSION

The results of this study suggest that family of origin relationship dynamics deserve further study with respect to how they impact adult quality of life for individuals with ADHD.

Pediatric bipolar mood disorder

The diagnosis of bipolar mood disorder (BP) in preadolescents (pediatric mania) has generated considerable controversy in terms of its estimated prevalence and validity as a diagnostic category. The relative paucity of systematic studies and the current diagnostic confusion related to the disorder are often attributed to the apparent discontinuities in the childhood versus adult presentation of the illness, namely, irritability as the predominant "mood" of mania and a continuous course of symptoms. The goal of this article is to review the current literature and identify sources of confusion relating to pediatric mania by considering results to date within a larger context that include findings from studies on (1) BP illness in adults, (2) mood disorders across the lifespan, (3) the role of development in symptom expression, and (4) patterns of heritability in psychiatric disorders. Whereas much remains to be investigated in the validation of the diagnosis for children, integrating results across studies may provide a framework for understanding the differences in the presentation of severe mood disorders in children and adults.

Measures of attention and hyperactivity symptoms in a high-risk sample of children of bipolar parents

BACKGROUND

To determine whether significant symptoms of inattention were present among the offspring of well-characterized bipolar parents.

METHODS

We included 53 offspring of 30 parents meeting DSM-IV criteria for bipolar disorder diagnosed by consensus on the basis of a SADS-L interview and a wealth of longitudinal clinical data. The unaffected parent had no lifetime history of a major psychiatric illness. Offspring, prospectively followed for up to 5 years, completed psychometric measures of attention and mood when judged to be at a good level of functioning (well, remitted or treated).

RESULTS

Those offspring with any lifetime psychiatric diagnosis endorsed more subjective problems with attention. However, there was no measurable difference on tasks of sustained attention between those with and those without a lifetime psychiatric illness including affective disorder. There was a significant association between self-reported symptoms of depression and inattention, but no association between either self-report measure and an objective measure of sustained attention.

LIMITATIONS

This study was not intended to be a comprehensive neuropsychological investigation of at risk offspring.

CONCLUSIONS

In this high-risk population, subjective difficulty with attention appeared to be state-dependent, associated with the degree of subjective distress related to an underlying psychiatric illness.

Unsuspected depressive mania in pre-pubertal Hispanic children referred for the treatment of 'depression' with history of social 'deviance'

BACKGROUND

Despite an emerging Literature on the mixed nature of pediatric mania, initial presentation with conduct problems continues to mislead mental health clinicians. The present report focuses on Hispanic pre-pubertal children referred for the treatment of depression in the context of conduct problems.

METHODS

Eleven boys and two girls received a structured psychiatric assessment in a practice setting to make sense of the presenting clinical complexity. Diagnoses were assigned using the DSM-IV criteria.

RESULTS

Ten of the boys and both girls met criteria for depressive mania. Their family histories were replete with affective disorder. Five (50%) of the boys and both of the girls (100%) with depressive mania had family histories of bipolar disorder. Six (60%) of the boys and neither of the girls with depressive mania had psychotic features. Those with depressive mania exhibited clear-cut circadian changes in symptomatology. Euphoria, oscillating with affective states indicative of psychic pain, was characteristically restricted to the evenings or nighttime. However, the drive to seek treatment had stemmed from social 'deviance'.

CONCLUSION

Children with depressive mania are often unrecognized in clinical settings. Boys with conduct problems may be disproportionately represented among such children. These data support Akiskal's hypothesis that externalizing (conduct) problems in clinically referred children with depression are indicative of bipolar disorder.

Affective illness in children and adolescents: patterns of presentation in relation to pubertal maturation and family history

Affective illness is now recognized as a common problem in all age groups, and the various patterns have been well documented in adults. The objective of this study was to evaluate the patterns of affective illness in children and determine changes with increasing age and family history. One hundred children/adolescents with affective illness (72 boys and 28 girls; age range 2-20 years; mean age 10 years), who were consecutively referred to the Pediatric Behavioral Neurology Program, Children's Medical Center at Dallas, were evaluated for the pattern and course of affective illness symptoms, family history, and pubertal stage. Seven patterns of affective illness were identified. In the 65 prepubertal children (Tanner stage 1), disorders with hypomanic/manic symptomatology were most common (47/65, 72%): mania (2/65, 3%), hypomania (8/65, 12%), cyclothymia (11/65, 17%), juvenile rapid-cycling bipolar disorder/ultradian cycling bipolar disorder (8/65, 12%), and dysthymia with bipolar features (18/65, 28%). In contrast, the 26 fully pubertal adolescents (Tanner stages 3-5) had a predominance of patterns with only depressive symptomatology (16/26, 61%): dysthymia (4/26, 15%) and depression (12/26, 46%), along with juvenile rapid-cycling bipolar disorder/ultradian cycling bipolar disorder (6/26, 23%). Affective illness, alcoholism, and drug abuse were prominent in the family histories, regardless of the child's pattern of symptoms. Family histories of character disorder and Briquet's syndrome were also common, but thought disorder, suicide, and homicide were infrequent. This study supports the clinical observation that the presentation of affective illness changes with age: manic features predominate in younger children, whereas depressive symptomatology is more evident with pubertal maturation.

National Institute of Mental Health research roundtable on prepubertal bipolar disorder

OBJECTIVE

A research roundtable meeting was convened at the National Institute of Mental Health on April 27, 2000, to discuss the existing controversial areas in the diagnosis of bipolar disorder in prepubertal children.

METHOD

Invited clinicians and researchers with expertise on bipolar disorder in children were asked to share and discuss their perspectives on diagnostic issues for bipolar disorder in prepubertal children.

RESULTS

The group reached agreement that diagnosis of bipolar disorder in prepubertal children is possible with currently available psychiatric assessment instruments. In addition to phenotypes that fit DSM-IV criteria for bipolar I and bipolar II, participants agreed on the existence of other phenotypic possibilities that do not meet diagnostic criteria. Bipolar not otherwise specified (NOS) was recommended as a "working diagnosis" for the non-DSM-IV phenotype.

CONCLUSIONS

Bipolar disorder exists and can be diagnosed in prepubertal children. In children who present with both the DSM-lV and non-DSM-IV phenotypes (i.e., those given a diagnosis of bipolar-NOS), assessment should include careful evaluation of all behaviors that are impairing. Moreover, these children should be monitored systematically to explore stability and change over time in diagnosis and impairment.

Mood disorders in children and adolescents: an epidemiologic perspective

Epidemiologic studies show that major depression is comparatively rare among children, but common among adolescents, with up to a 25% lifetime prevalence by the end of adolescence. Mania is much less common, with no more than a 2% lifetime prevalence by the end of adolescence. Developmental studies that include assessments of both hormonal changes and social changes through the pubertal transition are needed to investigate joint biological and environmental influences on the emergence of the gender difference in depression in puberty. Although subthreshold mood disorder symptoms are common, controversy exists about their clinical significance. This controversy is made more complex by methodologic uncertainties regarding inconsistent symptom reports obtained from parents, teachers, and children and by the pervasive existence of comorbidity. Retrospective reports about age of onset in adult studies suggest that at least 50% of youngsters with major depression and 90% of those with mania continue to have adult recurrences. These recurrences are mediated by adverse role transitions, such as truncated educational attainment and teenage childbearing, that typically occur before the time of initial treatment. Aggressive outreach and early treatment aimed at preventing the occurrence of adverse role effects might help decrease the persistence of child and adolescent mood disorders. Long-term follow-up studies are needed to resolve current uncertainties regarding nosology, methodology, and long-term treatment effects. Innovative epidemiologic research designs aimed at more quickly providing provisional information are also needed to advance understanding of long-term developmental processes.

Heterogeneity of childhood conduct disorder: further evidence of a subtype of conduct disorder linked to bipolar disorder

BACKGROUND

Although a small literature suggests that conduct disorder (CD) co-occurs with bipolar disorder (BPD), little is known about this overlap. Thus, we investigated the familial association of antisocial disorders (CD and/or antisocial personality disorder (ASPD)) and BPD among the first degree relatives of children with CD with and without comorbid BPD.

METHODS

We compared relatives of four proband groups defined by the presence or absence of CD and BPD in the proband: (1) CD+BPD (N=26 probands, 92 relatives; (2) BPD without CD (BPD) (N=19 probands, 53 relatives); (3) CD without BPD (CD) (N=16 probands, 58 relatives); and (4) controls without BPD or CD (N=102 probands, 338 relatives). All subjects were evaluated with structured diagnostic interviews. Diagnoses of relatives were made blind to the diagnoses of probands.

RESULTS

The results show high rates of antisocial disorders and BPD in relatives of children with CD+BPD. Moreover, antisocial disorders and BPD cosegregated among the relatives of children with CD+BPD. While relatives of both CD proband groups with and without BPD had high rates of CD/ASPD, the combined condition CD/ASPD+BPD was found exclusively among relatives of probands with CD+BPD.

LIMITATIONS

Since we pooled two datasets, subjects were not all evaluated at the same time. Also, the lack of direct psychiatric interviews with children younger than 12 may have decreased the sensitivity of some diagnoses.

CONCLUSIONS

These family-genetic findings suggest that CD and BPD represent separate disorders. Furthermore, they suggest that the comorbid condition of CD+BPD may be a distinct nosological entity. This suggests that clinicians treating CD or BPD children should consider the treatment implications of this comorbid condition.

Reliability of the Washington University in St. Louis Kiddie Schedule for Affective Disorders and Schizophrenia (WASH-U-KSADS) mania and rapid cycling sections

OBJECTIVE

To investigate the reliability of the Washington University in St. Louis Kiddie Schedule for Affective Disorders and Schizophrenia (WASH-U-KSADS) mania and rapid cycling sections.

METHOD

The 1986 version of the KSADS was modified and expanded to include onset and offset of each symptom for both current and lifetime episodes, expanded prepubertal mania and rapid cycling sections, and categories for attention-deficit/hyperactivity disorder and other DSM-IV diagnoses. To optimize diagnostic research, skip-outs were minimized. Subjects participated in the ongoing "Phenomenology and Course of Pediatric Bipolar Disorder" study. Mothers and children were interviewed separately by research nurses who were blind to diagnostic group status. In addition, ratings of off-site child psychiatrists, made from the narrative documentation given for each WASH-U-KSADS item, were compared with research nurse ratings. This work was performed between 1995 and 2000.

RESULTS

There was 100% interrater reliability, five consecutive times, as both interviewer and observer after 10 to 15 trials. The kappa values of comparisons between research nurse and off-site blind best-estimate ratings of mania and rapid cycling sections were excellent (0.74-1.00). High 6-month stability for mania diagnoses (85.7%) and for individual mania items and validity against parental and teacher reports were previously reported.

CONCLUSIONS

The WASH-U-KSADS mania and rapid cycling sections have acceptable reliability.

Prior stimulant treatment in adolescents with bipolar disorder: association with age at onset

OBJECTIVES

To compare demographic and clinical characteristics between bipolar adolescents with and without a history of stimulant treatment, we hypothesized that adolescents treated with stimulants would have an earlier age at onset of bipolar disorder, independent of co-occurring attention-deficit-hyperactivity disorder (ADHD).

METHOD

Thirty-four adolescents hospitalized with mania were assessed using the Washington University at St Louis Kiddie Schedule for Affective Disorders and Schizophrenia (WASH-U-KSADS). We systematically evaluated age at onset of bipolar disorder and pharmacological treatment history.

RESULTS

Bipolar adolescents with a history of stimulant exposure prior to the onset of bipolar disorder had an earlier age at onset of bipolar disorder than those without prior stimulant exposure. Additionally, bipolar adolescents treated with at least two stimulant medications had a younger age at onset compared with those who were treated with one stimulant. There was no difference in age at onset of bipolar disorder between bipolar adolescents with and without ADHD.

CONCLUSIONS

Our results suggest that stimulant treatment, independent of ADHD, is associated with younger age at onset of bipolar disorder. A behavioral sensitization model is proposed to explain our findings. There are several limitations to our study including the small sample size, the retrospective assessment of stimulant exposure and age at onset of bipolar disorder, and the inclusion of only hospitalized patients, who may be more likely to present with a severe illness. Nonetheless, future prospective longitudinal investigations that systematically assess the effects of stimulant medications in children with or at genetic risk for bipolar disorder are warranted.

Attention deficit hyperactivity disorder with bipolar disorder in girls: further evidence for a familial subtype?

BACKGROUND

To clarify the nosologic status of girls with attention deficit hyperactivity disorder (ADHD) who also satisfy diagnostic criteria for bipolar disorder (BPD).

METHODS

Using blind raters and structured psychiatric interviews, we examined 140 girls with ADHD, 122 non-ADHD comparisons and their 786 first degree relatives. Analyses tested specific hypotheses about the familial relationship between ADHD and bipolar disorder in girls.

RESULTS

After stratifying our ADHD sample into those with and without BPD, we found that: (1) relatives of both ADHD subgroups were at significantly greater risk for ADHD than relatives of non-ADHD controls, (2) the two subgroups did not significantly differ in their relatives' risk for ADHD; (3) an elevated risk for bipolar disorder was observed among relatives when the proband child had BPD but not ADHD alone; (4) weak evidence of cosegregation between ADHD and BPD, and (5) no evidence of a trend for random mating between ADHD parents and those with mania.

LIMITATIONS

Limitations of this study include the lack of direct interviewing of probands and the limited number of ADHD/BPD probands available.

CONCLUSIONS

These findings extend to girls what was previously documented in boys and suggest that comorbid ADHD with BPD in girls is familially distinct from other forms of ADHD and may be related to what others have termed childhood onset BPD. Future work could determine if this subgroup has a characteristic course, outcome and response to treatment.

Psychosocial functioning in a prepubertal and early adolescent bipolar disorder phenotype

OBJECTIVE

To compare psychosocial functioning (PF) in a prepubertal and early adolescent bipolar disorder phenotype (PEA-BP) sample to two comparison groups, i.e., attention-deficit/hyperactivity disorder (ADHD) and community controls (CC).

METHOD

There were 93 PEA-BP (with or without comorbid ADHD), 81 ADHD, and 94 CC subjects who were participants in an ongoing study, the Phenomenology and Course of Pediatric Bipolar Disorders. Cases in the PEA-BP and ADHD groups were outpatients obtained by consecutive new case ascertainment, and CC subjects were from a survey conducted by the Research Triangle Institute. To fit the study phenotype, PEA-BP subjects needed to have current DSM-IV mania or hypomania with elation and/or grandiosity as one criterion. Assessments for PF were by experienced research nurses who were blind to group status. Mothers and children were separately interviewed with the Psychosocial Schedule for School Age Children-Revised.

RESULTS

Compared with both ADHD and CC subjects, PEA-BP cases had significantly greater impairment on items that assessed maternal-child warmth, maternal-child and paternal-child tension, and peer relationships.

CONCLUSIONS

Clinicians need to consider PF deficits when planning interventions. In the PEA-BP group, there was a 43% rate of hypersexuality with a <1% rate of sexual abuse, supporting hypersexuality as a manifestation of child mania.

Parsing the association between bipolar, conduct, and substance use disorders: a familial risk analysis

BACKGROUND

Bipolar disorder has emerged as a risk factor for substance use disorders (alcohol or drug abuse or dependence) in youth; however, the association between bipolar disorder and substance use disorders is complicated by comorbidity with conduct disorder. We used familial risk analysis to disentangle the association between the three disorders.

METHODS

We compared relatives of four proband groups: 1) conduct disorder + bipolar disorder, 2) bipolar disorder without conduct disorder, 3) conduct disorder without bipolar disorder, and 4) control subjects without bipolar disorder or conduct disorder. All subjects were evaluated with structured diagnostic interviews. For the analysis of substance use disorders, Cox proportional hazard survival models were utilized to compare age-at-onset distributions.

RESULTS

Bipolar disorder in probands was a risk factor for both drug and alcohol addiction in relatives, independent of conduct disorder in probands, which was a risk factor for alcohol dependence in relatives independent of bipolar disorder in probands, but not for drug dependence. The effects of bipolar disorder and conduct disorder in probands combined additively to predict the risk for substance use disorders in relatives.

CONCLUSIONS

The combination of conduct disorder + bipolar disorder in youth predicts especially high rates of substance use disorders in relatives. These findings support previous results documenting that when bipolar disorder and conduct disorder occur comorbidly, both are validly diagnosed disorders.

Prodromal symptoms before onset of manic-depressive disorder suggested by first hospital admission histories

OBJECTIVE

A priority for research on manic-depressive or bipolar I disorder (BPI) for children and adolescents has been to search for early predictors of the illness.

METHOD

Medical record data were reviewed and systematically coded for a sample of 58 adult patients (32 males/26 females) with confirmed diagnoses of BPI to identify prodromal features and possible patterns of symptoms from the Amish Study.

RESULTS

The most frequently reported symptoms included episodic changes in mood (depressed and irritable) and energy plus anger dyscontrol, with no significant gender differences. A progression of ages is seen for the most commonly reported symptoms prior to age 16. The time interval was 9 to 12 years between appearance of the first symptoms and onset of a documented BPI syndrome.

CONCLUSIONS

The data suggest testable hypotheses about specific symptoms and behaviors that may be useful for the early detection of children at highest risk for developing manic-depressive disorder.

Failure to replicate an excess of the long dopamine D4 exon III repeat polymorphism in ADHD in a family-based study

The DRD4 exon III repeat polymorphism has been associated in adults with Novelty Seeking personality traits and in children with attention deficit hyperactivity disorder (ADHD) in some but not all studies. In a previous report we failed to observe preferential transmission of the long DRD4 repeat in ADHD compared to the haplotype relative risk (HRR) derived control group in a group of 49 triads (both parents and ADHD child) recruited in the Jerusalem area. In the current study we independently recruited an additional group of 49 triads from a different geographical location (Petak Tikvah) in Israel but having a similar ethnic background. In contrast to previous findings from a number of groups, in the current study an excess of the long DRD4 alleles was observed in the HRR control group compared to the ADHD subjects (Likelihood ratio = 5.50, P = 0. 02). In the expanded Israeli group of 98 triads so-far examined for the DRD4 repeat polymorphism there is an excess of the long alleles in the HRR control group (Likelihood ratio = 3.81, P = 0.05). These results attest to the complexity of ADHD inheritance and the likelihood that genetic heterogeneity characterizes this disorder especially across ethnic and cultural boundaries.

Psychiatric phenomenology of child and adolescent bipolar offspring

OBJECTIVE

To establish prodromal signs of and risk factors for childhood bipolar disorder (BD) by characterizing youths at high risk for BD.

METHOD

Structured diagnostic interviews were performed on 60 biological offspring of at least one parent with BD. Demographics, family histories, and parental history of childhood disruptive behavioral disorders were also assessed.

RESULTS

Fifty-one percent of bipolar offspring had a psychiatric disorder, most commonly attention-deficit/hyperactivity disorder (ADHD), major depression or dysthymia, and BD. BD in offspring tended to be associated with earlier parental symptom onset when compared with offspring without a psychiatric diagnosis. Bipolar parents with a history of childhood ADHD were more likely to have children with BD, but not ADHD. Offspring with bilineal risk had increased severity of depressed and irritable mood, lack of mood reactivity, and rejection sensitivity, while severity of grandiosity, euphoric mood, and decreased need for sleep were not preferentially associated with such offspring.

CONCLUSIONS

Bipolar offspring have high levels of psychopathology. Parental history of early-onset BD and/or childhood ADHD may increase the risk that their offspring will develop BD. Prodromal symptoms of childhood BD may include more subtle presentations of mood regulation difficulties and less presence of classic manic symptoms.

Bipolar disorder in youth

The debate regarding the possible existence of prepubertal bipolar illness has surfaced at various points in history. In its most recent incarnation, proponents of a childhood bipolar diagnosis argue that there is an early-onset form of bipolar illness that is highly comorbid and characterized by simultaneous irritability and depression. Others have suggested that childhood manic symptoms are more likely a nonspecific indicator of risk, or may be the result of symptom overlap with various other forms of childhood pathology. This article briefly reviews pertinent findings from epidemiologic, developmental, family, and treatment studies that shed light on the etiology, phenomenology, and developmental significance of manic symptoms in young people.

Genetic influences on attention deficit hyperactivity disorder

In this article we review behavioral and molecular genetics studies of attention deficit hyperactivity disorder (ADHD). Family, twin, and adoption studies, along with segregation analyses and molecular genetic studies, all support the hypothesis that both genetic and environmental factors contribute to the etiology of ADHD. Despite this strong evidence for the familial transmission of ADHD, the mode of transmission requires further clarification. In addition, because ADHD appears to be genetically heterogeneous, more work is needed to delineate genetically homogeneous subtypes and describe the range of expression of their underlying genotypes.

Validity of DSM-IV subtypes of attention-deficit/hyperactivity disorder: a family study perspective

OBJECTIVE

To test the hypothesis that the clinical severity of subtypes paralleled a gradient of familial severity.

METHOD

One hundred forty children with attention-deficit/hyperactivity disorder (ADHD) and 120 normal control children and their biological relatives were studied: Because these data had been collected prior to the publication of DSM-IV, DSM-III-R symptoms were used to approximate DSM-IV subtypes using a method the authors had validated in prior work.

RESULTS

The first prediction from the hypothesis was true: rates of ADHD among relatives of each subtype group were greater than rates among relatives of controls. But the second prediction did not hold: rates of ADHD were not significantly higher among relatives of combined-typed probands compared with relatives of other probands. The "gradient model" also predicted that subtypes would not "breed true" (i.e., the subtype of the relative would not be the same as that of the proband). The prediction of nonspecificity was refuted for the inattentive and combined subtypes, but hyperactive-impulsive ADHD was found almost exclusively among relatives of hyperactive-impulsive probands.

CONCLUSIONS

Although the results are limited by some small subsamples along with the use of a DSM-III-R-ascertained sample, they provide little evidence for the idea that DSM-IV subtypes of ADHD correspond to familially distinct conditions. They also do not confirm the idea that the subtypes fall along a gradient of familial severity. Instead, they suggest that symptom differences among subtypes are due to nonfamilial, environmental causes.

Toward guidelines for pedigree selection in genetic studies of attention deficit hyperactivity disorder

Converging evidence from family, twin, and adoption studies points to a substantial genetic component of the etiology of attention deficit hyperactivity disorder (ADHD). These data about ADHD have motivated molecular genetic studies of the disorder, which have produced intriguing but somewhat conflicting results. Some studies have reported associations with candidate genes and others not. Our review of the literature shows that one problem facing molecular genetic studies of ADHD is that its recurrence risk to first-degree relatives is only about five times higher than the population prevalence. This suggests that, to produce consistently replicated results, molecular genetic studies should either use much larger samples or should select those families in which genes exert the largest effect. Risch [(1990a) Am J Hum Genet 46:222-228; (1990b) Am J Hum Genet 46:229-241] proved that the statistical power of a linkage study increases with the magnitude of risk ratios (lambda's) computed by dividing the affection rate among each relative type to the rate of affection in the population. Our prior work suggests two dimensions of genetic heterogeneity that might be useful for selecting ADHD subjects for molecular genetic studies: comorbidity with conduct disorder and persistence of ADHD into adolescence. This paper shows that these sub-phenotypes are useful for molecular genetic studies because (1) they have much higher empirical lambda values and (2) they affect a substantial minority of ADHD patients.

Serotonin transporter gene (HTTLPR) is not in linkage disequilibrium with prepubertal and early adolescent bipolarity

BACKGROUND

As part of an ongoing, larger study, "Phenomenology and Course of Pediatric Bipolarity", a subset of prepubertal and early adolescent onset bipolar (PEA-BP) probands, on whom trio blood collection was complete, were used to study genetic transmission of the serotonin transporter linked promoter region (HTTLPR) short and long alleles using the transmission disequilibrium test(TDT). The HTTLPR alleles were selected based on postulated serotonergic mechanisms for PEA-BP and on the burgeoning number of HTTLPR allele studies in bipolar (BP) adults.

METHODS

There were 46 complete trios of PEA-BP probands and both biological parents. Probands had a mean age of 11.1 +/- 3.0 years and a mean age of onset of PEA-BP of 8.1 +/- 4.0 years. Comprehensive diagnostic assessments included a semi-structured research interview, the WASH-U-KSADS, administered separately to mothers and to children by blind raters. Probands manifested severe impairment (CGAS 43.9 +/- 8.9), elated mood (84.8%), grandiosity (78.3%), rapid cycling (78.3%) and psychosis (63.0%). The HTTLPR length variant was genotyped using fluorescently labeled primers and automated capillary electrophoresis using laser-induced fluorescence.

RESULTS

The TDT was not significant (TDT chi square = .020, df = 1, p = .89).

CONCLUSIONS

This negative result is consistent with the one negative TDT and two negative linkage studies of HTTLPR alleles in bipolar adults in the literature.

Further evidence of a bidirectional overlap between juvenile mania and conduct disorder in children

OBJECTIVE

To investigate systematically the overlap between mania and conduct disorder (CD) in a sample of consecutively referred youths. It was hypothesized that neither CD nor manic symptoms were secondary to the other disorder and that children with the 2 disorders would have correlates of both.

METHOD

Subjects were consecutively referred children and adolescents meeting DSM-III-R diagnostic criteria on structured diagnostic interview for CD (n = 116), mania (n = 110), and CD + mania (n = 76).

RESULTS

Of 186 children and adolescents with mania and of 192 with CD, 76 satisfied criteria for both CD and mania, representing 40% of youths with CD and 41% of youths with mania, respectively. Examination of the clinical features, patterns of psychiatric comorbidity, and functioning in multiple domains showed that children with CD and mania had similar features of each disorder irrespective of the comorbidity with the other disorder.

CONCLUSIONS

The data suggest that when mania and CD co-occur in children, both are correctly diagnosed. In these comorbid cases, CD symptoms should not be viewed as secondary to mania and manic symptoms should not be viewed as secondary to CD.

Evaluation of ADHD typology in three contrasting samples: a latent class approach

OBJECTIVE

To identify subtypes of attention-deficit/hyperactivity disorder (ADHD) and characterize them as either categorical or continuous; to investigate familial resemblance for ADHD among sibling pairs; and to test the robustness of all results by using contrasting data sets.

METHOD

Latent class analysis was applied to the ADHD symptom profiles obtained from parents or best informant about their offspring in 3 samples: a population-based set of female adolescent twins (724 monozygotic pairs, 594 dizygotic pairs) and male (N = 425) and female (N = 430) child and adolescent offspring ascertained from high-risk alcoholic families.

RESULTS

Latent class analysis revealed 2 categories of clinically significant ADHD which were replicated in all 3 study groups: a subtype with high endorsements of ADHD inattention symptoms and a second combined type with high endorsements of both inattention and hyperactivity-impulsivity items. Both appeared to be continuous across all 3 data groups. The high-risk families contained a class in which members heavily endorsed the ADHD "fidget" item but not other ADHD items. A large proportion of the monozygotic sibs (80%) versus a smaller proportion of dizygotic sibs (52%) were assigned to the same latent class. Among the high-risk children and adolescents, 51% of the female and 41% of the male siblings were concordant for class membership.

CONCLUSIONS

The pattern of latent classes suggested that ADHD consists of an inattentive and a combined subtype, within each of which lies a dimensional domain. These analyses further support that genetic factors are significant determinants of latent class membership.

Neurobiology of attention-deficit hyperactivity disorder

Attention-deficit hyperactivity disorder (ADHD) is an early-onset, clinically heterogeneous disorder of inattention, hyperactivity, and impulsivity. Family, twin, adoption, segregation analysis, and molecular genetic studies show that is has a substantial genetic component. Although their results are still tentative, molecular genetic studies suggest that three genes may increase the susceptibility to ADHD: the D4 dopamine receptor gene, the dopamine transporter gene, and the D2 dopamine receptor gene. Studies of environmental adversity have implicated pregnancy and delivery complications, marital distress, family dysfunction, and low social class. The pattern of neuropsychological deficits found in ADHD children implicate executive functions and working memory; this pattern is similar to what has been found among adults with frontal lobe damage, which suggests that the frontal cortex or regions projecting to the frontal cortex are dysfunctional in at least some ADHD children. Moreover, neuroimaging studies implicate frontosubcortical pathways in ADHD. Notably, these pathways are rich in catecholamines, which have been implicated in ADHD by the mechanism of action of stimulants--the class of drugs that effectively treats many ADHD children. Yet human studies of the catecholamine hypothesis of ADHD have produced conflicting results, perhaps due to the insensitivity of peripheral measures.

Premorbid functioning in adolescent onset bipolar I disorder: a preliminary report from an ongoing study

BACKGROUND

This study reports on premorbid academic and peer functioning and psychiatric illness in a rigorously diagnosed sample (N = 28) of adolescent onset bipolar I patients.

METHODS

Premorbid functioning was assessed by parental report and review of the Ontario School Record (OSR). Premorbid psychiatric diagnoses were assigned on the basis of all information gathered.

RESULTS

Overall, findings suggest that this cohort demonstrates good to excellent peer and academic functioning prior to illness onset. Rates of premorbid psychiatric illnesses were similar to that described in epidemiologic samples.

CONCLUSIONS

Results are discussed in relation to current understanding of early onset bipolar illness and directions for future research.

Young referred boys with DICA-P manic symptoms vs. two comparison groups

A total of 23 boys met DICA-P manic symptom and clustering criteria in a diagnostic investigation of 233 outpatient boys between ages 6 and 10. In this manic-symptom group, the most frequently endorsed of an average of five manic symptoms were extreme mood changes, difficulty concentrating, feeling too 'up' to sit still, and racing thoughts. Comparison groups were 23 non-manic boys seen next in the investigation and 23 non-manic boys matched to the manic-symptom boys on symptoms of three comorbid disruptive disorders (ADHD, ODD and CD). Manic-symptom boys differed significantly from next-seen boys, but not from matched comorbid boys, in number of oppositional symptoms and pervasiveness of problems. Manic-symptom boys differed significantly from next-seen boys on six of eight mother-rated RCBCL factors. In contrast, manic-symptom and matched comorbid boys did not differ on any of eight RCBCL factors, which suggests that the RCBCL differences can be attributed to shared ADHD, ODD and/or CD. However, manic-symptom and matched comorbid boys tended to differ on RCBCL Anxiety/Depression. On the teacher-rated TRF, manic-symptom boys were rated higher than next-seen boys on four internalizing factors, and higher than matched comorbid boys on two of those factors, including Anxiety/Depression. Thus, manic symptomatology also predicted substantial emotionality, which was not a controlled comorbidity. The findings of this and other studies suggest that there is a mania dimension or syndrome, which may be an indicator of true bipolar disorder--or simply a marker for disruptive comorbidity, behavioral and emotional multimorbidity, or general severity of psychopathology.

Manic symptoms in psychiatrically hospitalized children--what do they mean?

OBJECTIVE

To examine the clinical implications of manic symptoms in psychiatrically hospitalized children aged 5-12.

METHODS

DSMIIIR manic symptoms, along with symptoms of other psychiatric disorders, were rated by parents and teachers on the Child Symptom Inventory IIIR prior to hospitalization. The Child Behavior Checklist (CBCL; was also completed. During hospitalization children were evaluated by structured interview (K-SADS-E), and numerous rating scales weekly. Children with symptoms of mania (mania criteria with/without episodes) were compared to those without mania. Severity of attention deficit hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), depression, CBCL factors, and comparable factors from teacher and parent inpatient rating scales were examined. Finally, a subgroup of both groups of children treated with stimulants were compared at baseline and at least two weeks of treatment.

RESULTS

Children with manic symptoms had more severe ADHD, ODD and depression symptoms. CBCL scores on aggression, social and thought problems were higher. Teachers and nursing staff made similar observations. Time in hospital was greater for children with manic symptoms. Both groups improved significantly on stimulant medication though reduction in overall psychopathology was often modest.

CONCLUSIONS

Manic symptoms, regardless of whether or not they represent bipolar disorder, are a marker of serious psychopathology and treatment resistance.

Clinical features of children with both ADHD and mania: does ascertainment source make a difference?

OBJECTIVE

We evaluated the structural diagnostic results of children ascertained through an ADHD diagnosis with comorbid mania to determine if they have the same phenotype as children ascertained through a mania diagnosis with comorbid ADHD.

METHOD

We compared a sample of children participating in a family genetic study of ADHD to a sample of children ascertained through a study of childhood mania.

RESULTS

Similar correlates of ADHD and mania were observed in children satisfying criteria for both disorders irrespective of ascertainment source.

CONCLUSIONS

Findings suggest that children with mania and ADHD have two disorders, their features not varying with the primary diagnostic focus.

LIMITATIONS

The results may have been limited by small sample size.

CLINICAL RELEVANCE

Because the coexistence of ADHD and mania seriously complicates the course and treatment of children, understanding the compatibility of these disorders has important clinical implications in the management of this population.

Neuropsychiatric disorders

Neuropsychiatric disorders of childhood include autism spectrum disorders, disorders comprising attention deficits (attention-deficit-hyperactivity disorder and deficits in attention, motor control and perception), tics (motor or vocal, or both), and obsessions and compulsions (obsessive-compulsive disorder). They affect a small proportion of the child population. They can now reliably be diagnosed, and are valid and clinically meaningful conditions. Effective interventions are available for most of these disorders.

Attention-deficit hyperactivity disorder with bipolar disorder: a familial subtype?

OBJECTIVE

To clarify the nosological status of children with attention-deficit hyperactivity disorder (ADHD) who also satisfy diagnostic criteria for bipolar disorder (BPD).

METHOD

Blind raters and structured psychiatric interviews were used to examine 140 children with ADHD, a sample of 120 non-ADHD comparisons, and their 822 first-degree relatives. Data analyses tested specific hypotheses about the familial relationship between ADHD and BPD.

RESULTS

After stratifying the ADHD sample into those with and without BPD, the authors found that (1) relatives of both ADHD subgroups were at significantly greater risk for ADHD than relatives of non-ADHD controls; (2) the two subgroups did not differ significantly from one another in their relatives' risk for ADHD; (3) a fivefold elevated risk for BPD was observed among relatives when the proband child had BPD but not when the proband had ADHD alone; (4) an elevated risk for major depression with severe impairment was found for relatives of ADHD + BPD probands; (5) both ADHD and BPD occurred in the same relatives more often than expected by chance alone; and (6) there was a trend for random mating between ADHD parents and those with mania.

CONCLUSIONS

The data suggest that comorbid ADHD with BPD is familially distinct from other forms of ADHD and may be related to what others have termed childhood-onset BPD.

Is comorbidity with ADHD a marker for juvenile-onset mania?

OBJECTIVE

To compare the characteristics and correlates of mania in referred adolescents and to determine whether attention-deficit hyperactivity disorder (ADHD) is a marker of very early onset mania.

METHOD

From 637 consecutive admissions, 68 children (< or = 12 years) and 42 adolescents (> 13 years) who satisfied criteria for mania were recruited. These were compared with the 527 nonmanic referrals and 100 normal controls.

RESULTS

With the exception of comorbidity with ADHD, there were more similarities than differences between the children and adolescents with mania in course and correlates. There was an inverse relationship between the rates of comorbid ADHD and age of onset of mania: higher in manic children intermediate in adolescents with childhood-onset mania, and lower in adolescents with adolescent-onset mania.

CONCLUSIONS

ADHD is more common in childhood-onset compared with adolescent-onset cases of bipolar disorder, suggesting that in some cases, ADHD may signal a very early onset of bipolar disorder. Clinical similarities between the child- and adolescent-onset cases provide evidence for the clinical validity of childhood-onset mania.

Conduct disorder with and without mania in a referred sample of ADHD children

OBJECTIVE

To test the hypothesis that dysphoric and non-dysphoric types of CD could be distinguished from one another in their patterns of familiality, adversity, and comorbidity.

METHODS

We examined 140 ADHD and 120 normal controls at baseline and 4 years later using assessments from multiple domains. We compared ADHD subgroups with and without conduct (CD) and bipolar (BPD) disorders on psychiatric outcomes at a 4-year follow-up, familial psychopathology and psychosocial functioning.

RESULTS

We found that ADHD children with both disorders had higher familial and personal risk for mood disorders than those with CD only, who had a higher personal risk for antisocial personality disorder. Among ADHD probands, having both CD and BPD was associated with poorer functioning and an increased risk for psychiatric hospitalization.

DISCUSSION

Although preliminary, our findings suggest that the distinction between dysphoric and non-dysphoric CD may be clinically meaningful. If confirmed, our findings could have important diagnostic and therapeutic implications for the management of antisocial youth.