Parental diagnoses bipolar disorder in youth with narrow phenotype or severe mood dysregulation

Objective: Controversy exists regarding whether nonepisodic irritability and hyperarousal (severe mood dysregulation) is a phenotype of pediatric bipolar disorder. The authors compared axis I diagnoses in parents of children with narrow phenotype bipolar disorder and parents of youth with severe mood dysregulation. Method: Parents of youth with narrow phenotype bipolar disorder (proband N=33, parent N=42) and youth with severe mood dysregulation (proband N=30, parent N=37) were interviewed by clinicians who were blind to the child's diagnostic status using the Diagnostic Interview for Genetic Studies. Results: Compared to parents of youth with severe mood dysregulation, parents of youth with narrow phenotype bipolar disorder were significantly more likely to be diagnosed with bipolar disorder. There were no other diagnostic differences between the two groups. Conclusions: These data suggest that narrow phenotype bipolar disorder may be distinct from severe mood dysregulation in terms of familial aggregation. Additionally, the familiality of narrow phenotype bipolar disorder and adult DSM-IV bipolar disorder is high.