As in all psychiatric disorders, maintenance therapy of bipolar disorder is a treatment carried out for a long period, with a goal of decreasing the probability, frequency, or severity of future
episodes. Because bipolar disorder is by its nature a recurrent condition, some would argue that as soon as it is definitively di-agnosed (e.g., after a single manic episode not attributable to a medical or neurological cause), maintenance therapy is indicated (Table 78.10). More conservative psychiatrists advocate waiting until the frequency and severity of a patient’s disorder become apparent, hoping to avoid long-term exposure to medication that may not be required. The counter to this concern is evidence sug-gesting that recurrent episodes in themselves may worsen treat-ment response and long-term outcome (Gelenberg et al., 1989).
Patients with rapid-cycling bipolar disorder – defined as four or more affective episodes in 1 year, with or without an intervening period of euthymia – tend to be less responsive to lithium treat-ment (Dunner and Fieve, 1974). Whether rapid cycling is a natu-ral progression of the illness or a separate disorder has yet to be determined. The onset of rapid cycling has been associated with antidepressant drugs (especially tricyclic antidepressants) and hypothyroidism (Wehr and Goodwin, 1987; Roy-Byrne et al., 1984). Some people also experience ultrarapid cycling, switching between moods in a period of days or even hours. Various thera-peutic approaches have been investigated for treating patients with rapid-cycling bipolar disorder.