Diagnostic subtypes of bipolar disorder in older versus younger adults

Abstract

To investigate differences in diagnostic subtypes of bipolar disorder as according to ICD-10 between patients whose first contact with psychiatric health care occurs late in life (over 50 years of age) and patients who have first contact earlier in life (50 years of age or below). From 1994 to 2002 all patients who received a diagnosis of a manic episode or bipolar disorder at initial contact with the mental healthcare system, whether outpatient or inpatient, were identified in Denmark's nationwide register. A total of 852 (49.6%) patients, who were over age 50, and 867 patients, who were 50 or below, received a diagnosis of a manic episode or bipolar disorder at the first contact ever. Older inpatients presented with psychotic symptoms (35.4%) significantly less than younger inpatients (42.6%) due specifically to a lower prevalence of manic episodes with psychotic symptoms. Conversely, older inpatients more often presented with severe depressive episodes with psychotic symptoms than younger inpatients (32.0% versus 17.0%). Among outpatients, no significant differences were found between patients older than 50 years and patients 50 years of age or younger. However, a bimodal distribution of age at first outpatient contact was found with an intermode of 65 years and outpatients older than 65 years more often presented with severe depressive episodes with psychosis. Bipolar patients who are older at first psychiatric hospitalization (>50 years) present less with psychotic manic episodes and more with severe depressive episodes with psychosis than younger patients. The distribution of age at first outpatient contact is bimodal with an intermode of 65 years and outpatients older than 65 years more often present with severe depressive episodes with psychosis.