Notably, even accounting for family psychopathology, maternal warmth predicted outcome. Kim and Miklowitz49
reported on the role of high expressed emotion, akin to low maternal warmth, in the course of adult BP-I, similar to the role of low maternal warmth as a predictor in subjects with child BP-I. However, there are data that do not support an effect of high expressed emotion on the course of adult BP-I,50
so that further research to better define the role of low maternal warmth/high expressed emotion is warranted.
One area of controversy has been the high prevalence of daily cycling (ultradian cycling) during episodes found by several investigative groups.4,5,12,15–17
Because a child must have 4 hours or more per day to count as mania and because the mean number of cycles per day was 3.7 (SD, 2.1), these subjects were spending most of the day in a pathological mood episode. The clinical importance of daily cycling is that a euphoric child can very quickly become seriously depressed and suicidal. Daily cycling continued to be highly prevalent when the subjects with child BP-I reached adulthood. Is this just a peculiarity of some samples, or does the detailed questioning about daily cycling on the WASH-U-KSADS increase the likelihood of finding this phenomenon? The WASHU- KSADS is also being used in the ongoing NIMH-funded “Treatment of Early Age Mania (TEAM)” study. In the TEAM study, daily cycles were found in 98.6% of subjects from 6 national sites,12
which strongly supports that daily cycles are more likely to be found when they are asked about.
Characteristics of second and third episodes also showed that subjects still had substantial morbidity, including long episode duration, psychosis, and daily cycling. Of note, the score on the CGAS (and the Global Assessment Scale in older subjects) was significantly lower during second and third episodes and in subjects who were 18.0 years or older. This likely reflects how functioning in children may be enhanced by parental behaviors (eg, children are taken to school as opposed to adults, who have to show up for work on their own).
In grown-up subjects with child BP-I, the 44.4% frequency of manic episodes was 13 to 44 times higher than population prevalences,51,52
strongly supporting continuity between child and adult BP-I. Subjects with child BP-I who were grown up at the 8-year follow-up constituted approximately half the sample. However, even if all subjects younger than 18.0 years at the 8-year follow-up never had episodes of BP-I as adults, the overall significance of the findings would be similar, because the rate would still be 6 to 22 times higher than population prevalences.51,52
In a study of adults with first episodes of DSM-IV
mania, 20% had a new manic episode during a 2-year follow-up.53
That study used a treated, inpatient population, which is possibly related to the better outcome.
Recent prospective work from Judd et al18
on the course of adults with BP-I found that subjects were ill with mood symptoms 47.3% of weeks. These findings are similar to those in this report, in which subjects with child BP-I, both those younger than 18.0 years and those 18.0 years or older, were ill with mood episodes 65.5% and 49.4% of weeks, respectively.
In the family study data from this cohort, both child-onset and adult-onset BP-I occurred within the same families, 8
further bolstering continuity across the age span. In addition, the prevalence of comorbid SUD in the subjects with child BP-I who were 18.0 years or older, 35.2%, was similar to that reported for adults with BP-I, 42.4%.44
Given that subjects with child BP-I who reached age 18.0 years are not yet through the age of risk for SUDs, the 35.2% found may be higher at future follow-up assessment times. It is difficult to compare the rates of ADHD in the subjects with child BP-I who reached adulthood during follow-up with studies of adult BP-I, because ADHD was not systematically assessed in adult BP-I.44
Whether there is a relationship between child BP-I symptomatology and concurrent parental mood disorder was not examined in this sample. Given the recent work of Weissman et al54
on the relationship between severity of child depressive symptoms and concurrent maternal depression, similar studies for child BP-I are warranted. There are, however, data that support a less deleterious effect of maternal BP-I than maternal MDD on child-aged offspring.55
Limitations of this work are that subjects were largely of higher socioeconomic status (see descriptionin the “Methods” section), so generalization to lower socioeconomic status cannot be known. More frequent assessments and the course of BP-II and BP not otherwise specified are important areas that were not included in this project.
In conclusion, mounting data support the existence of child BP-I, and the severity and chronicity of this disorder argue strongly for large efforts toward understanding the neurobiology and for developing prevention and intervention strategies.