Age effects on early-onset bipolar illness may include changes in affective features and recovery. Age effects on the pharmacokinetics of lithium are clinically relevant. Average age at onset is relatively late among geriatric bipolars. Late-onset bipolar disorder is associated with lower rate of familial illness than early-onset cases and greater medical and neurologic comorbidity. The limited literature available points to the need for further studies of geriatric bipolar disorder. In such investigation, the distinction between age and age at onset effects provides a framework within which to enhance knowledge of psychopathology, to expand understanding of natural history and the impact of therapeutic interventions, and to study mechanisms.
