Affiliation: College of Arts and Sciences, Department of Psychology and Neuroscience
Four subtypes of pediatric bipolar disorder (PBD) - bipolar I, bipolar II, cyclothymia and bipolar not otherwise specified (NOS) - are defined in DSM-IV-TR. However, these definitions are not followed consistently by research investigators or clinicians, resulting in a lack of agreement and understanding regarding the diagnosis of PBD. The present study uses the diagnostic validation method first proposed by Robins and Guze (1970), to systematically evaluate cyclothymic disorder as a distinct diagnostic subtype of bipolar disorder (BP). Using a clinical sample (N= 827), participants with cyclothymic disorder (N=52) were compared to participants with other BP disorders and to participants with non-affective disorders. Results indicate that cyclothymic disorder shares many characteristics with other bipolar subtypes, supporting its inclusion on the spectrum. Additionally, cyclothymia could be reliably differentiated from non-bipolar disorders based on irritability, sleep disturbance, age of symptom onset, comorbid diagnoses, and family history. These results highlight areas for future research.