These terms describe stages of treatment. When somebody is currently experiencing a mood episode, he is said to be in the acute stage. Here the goal is to get the most severe symptoms of mania or depression under control. Once the individual is somewhat stable, the continuation phase of treatment, the next six to twelve months, is a time to address residual symptoms and functional impairments, such as conflicted relationships, work, housing, and so forth. The continuation phase is also a period of high risk for a relapse, so frequent clinical contacts and a tolerable medication regimen are important.
The maintenance phase of treatment occurs after the symptoms have resolved. Medications are now used to decrease the likelihood of recurrence, and other treatments, such as psychotherapy, are geared toward maintaining and improving overall functioning and quality of life.