• age of onset;
  • bipolar disorder;
  • mania

Objective:  To compare the clinical presentation of patients with early-onset (age <18 years) and typical-onset (age 20–30 years) bipolar disorder at the time of first hospitalization.

Methods:  Patients, aged 12–45 years at their first psychiatric hospitalization, with a DSM-IV diagnosis of bipolar disorder, manic or mixed, were evaluated on measures of manic, depressive, and positive psychotic symptoms. Differences in symptom profiles between early- and typical-onset groups were examined.

Results:  One hundred three early-onset and 58 typical-onset patients were compared. Mixed episodes were more common in the early-onset group, while psychotic features and current substance use were more common in the typical-onset group. There was no significant difference in manic symptom severity ratings between early- and typical-onset groups (F = 1.8, df = 11, 144, p = 0.06). However, these groups differed in depressive (F = 4.2, df = 16, 139, p < 0.001) and positive psychotic (F = 2.8, df = 16, 139, p = 0.001) symptom profiles. Typical-onset bipolar patients reported more severe weight loss and formal thought disorder compared with early-onset patients.

Conclusions:  Depressive and positive psychotic symptoms may differ in association with age at onset among patients with bipolar disorder. Additional studies are necessary to determine whether homogeneous phenotypes of bipolar disorder can be delineated based upon age at onset.