Comorbidity between ADHD and symptoms of bipolar disorder in a community sample of children and adolescents.

The prevalence and frequency of comorbidity of possible bipolar disorder was examined with attention-deficit hyperactivity disorder (ADHD) in a nonreferred population of twins. Children and adolescents aged 7 to 18 years with a history of manic symptoms were identified from a population-based twin sample obtained from state birth records (n = 1610). The sample was enriched for ADHD; however, there was also a random control sample (n = 466), which allowed a look at the population prevalence of the disorder. Juveniles with threshold or below threshold manic episodes were further assessed for comorbidity with Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994) and population-defined ADHD subtypes (from latent class analysis) using Fisher's exact test. Nine juveniles who exhibited DSM-IV manic (n = 1), hypomanic (n = 2) or below threshold episodes (n = 6) were identified. The population prevalence of broadly defined mania in the random sample was 0.2%. The possible manic episodes showed significant comorbidity with population-defined severe combined and talkative ADHD subtypes. It can be concluded that there is a significant association of bipolar symptoms with two population-defined subtypes of ADHD. Episodes of possible bipolar disorders as defined by DSM-IV are uncommon in this nonreferred sample. Children and adolescents with ADHD appear to be only modestly at increased risk for bipolar disorders.

Estimation of prevalence of DSM-IV and latent class-defined ADHD subtypes in a population-based sample of child and adolescent twins.

The goal of this study is to determine the prevalence and age of onset of Diagnostic and Statistical Manual of Mental Disorders and latent class-derived attention deficit/hyperactivity disorder (ADHD) subtypes in a population-based twin sample of boys and girls. Missouri birth records identified families with a twin pair 7 to 18 years of age. Telephone screening interviews for ADHD symptoms were completed for 5007 families. Diagnostic assessments were administered to 564 families with at least one twin meeting screening criteria, plus 183 control families. Prevalence and age of onset for both ADHD nosologies were calculated by sex and zygosity from parent report data. The prevalence of any DSM-IV ADHD was 6.2% overall, 7.4% in boys and 3.9% in girls. The inattentive subtype was most common in boys; the combined subtype was most common in girls. The mean age of onset of symptoms in children with any DSM-IV ADHD was 3.5 years, with no significant differences between boys and girls. Prevalences of latent class defined ADHD subtypes also varied by sex with the severe inattentive and combined classes more common in boys than girls. The age of onset of symptoms did not differ between boys and girls but were higher than in the DSM-IV subtypes. Findings in this twin sample showed that clinically significant ADHD, defined by either DSM-IV or latent class criterion, has an early age of onset and is more common in boys than girls. As clinical samples are most commonly composed of male combined subtypes, the inattentive subtype of both sexes in the general population is an under-treated segment of the general population.

Reliability and stability of a semistructured DSM-IV interview designed for family studies.

OBJECTIVE: To determine the interrater reliability and stability of diagnoses, and to compare the results of in-person versus telephone administration of the Missouri Assessment of Genetics Interview for Children (the MAGIC), a new, semistructured, glossary-based diagnostic interview for children and adolescents. METHOD: The interview was developed for a large-scale epidemiological family genetics study. For reliability measures, parent report on offspring, child self-report, and adolescent self-report interviews were independently scored by two different raters on a population-based sample of respondents. The stability of diagnoses was assessed by comparing repeat interviews of parents, children, and adolescents, separated on average by 13 months. Frequencies of parent and adolescent report of disorders were determined for telephone and in-person interviews. RESULTS: High interrater reliabilities were achieved for individual DSM-IV symptoms and diagnoses and for individual characteristics of diagnostic domains, including number, clustering, duration, and impairment of symptoms. The stability of diagnoses was also high for parents and adolescents. No significant differences in the prevalence of attention-deficit/hyperactivity disorder and major depressive disorder were found for interviews administered in person or by telephone. CONCLUSIONS: The MAGIC demonstrates high interrater reliability and stability for DSM-IV symptoms and diagnoses.

Reliability and stability of mothers' reports about their pregnancies with twins.

The objective of this study was to determine if mothers' retrospective reports about events in their pregnancies with twins are reliable and stable. Six hundred and twenty-four mothers completed psychiatric interviews about their twins. These interviews also contained questions about the mothers' pregnancies, the perinatal period, and the child's early development. The mothers reported first on one twin and then on the other with interviews spaced from 3 days to 2 weeks apart. Thus mothers reported on the same pregnancy twice. Of these mothers, 47 were re-interviewed 6 to 18 months later by raters blind to the results of the initial interview. The twin design allowed us to compare the short-term reliability of the 624 mothers' reports of the same pregnancy. The re-interview of the 47 mothers enabled us to compare the stability of reports over a longer time period. Agreement between the reports was measured with the kappa statistic. Kappas were good to excellent for the short-term reports of pregnancy for each twin for the 624 mothers. Kappas were equally high for the 47 mothers that were re-interviewed 6 to 18 months later. Mothers show good reliability and stability of reporting about events during pregnancy.

Discrimination of DSM-IV and latent class attention-deficit/hyperactivity disorder subtypes by educational and cognitive performance in a population-based sample of child and adolescent twins.

OBJECTIVE: Despite the general use of DSM-IV attention-deficit/hyperactivity disorder (ADHD) subtypes, there is controversy over the optimal phenotyping strategy for this disorder.This report contrasts two ADHD subtyping approaches on the prediction of cognitive function and educational achievement. METHOD: ADHD subtypes were determined using DSM-IV and latent class approaches for a population sample of 1,154 child and adolescent twins using parent report data. Twins completed cognitive and achievement testing and parents reported on school grades, special education placement, and history of being held back in school. RESULTS: The DSM-IV primarily inattentive and combined subtype ADHD groups showed significant deficits in cognitive and achievement testing, worse grades, and increased use of special education resources compared with the primarily hyperactive/impulsive subtype and no-ADHD groups. Clinically relevant and less severe latent class ADHD subtypes were also associated with deficits in cognitive and achievement testing, grades, and special education use. CONCLUSIONS: DSM-IV primarily inattentive and combined subtypes of ADHD have similar significant patterns of cognitive and academic dysfunction in the general population. Latent class-defined ADHD subtypes also have patterns of serious cognitive and achievement deficits.