Agitated depression in bipolar I disorder: prevalence, phenomenology, and outcome.

Objective: The study aimed to explore how prevalent agitated depression is in bipolar I disorder, whether it represents a mixed state, and whether it differs from nonagitated depression with respect to course and outcome.
Method: From 313 bipolar I patients with an index episode of major depression, the authors selected those fulfilling Research Diagnostic Criteria for agitated depression. These 61 patients were compared to 61 randomly recruited bipolar I patients with an index episode of nonagitated depression and 61 randomly recruited bipolar I patients with an index episode of mania regarding demographic, historical, and clinical features. The two depressive groups were also compared regarding time to recovery from the index episode, treatment received for that episode, percentage of time spent in an affective episode during a prospective observation period, and 5-year outcome.
Results: Patients with agitated depression were consistently not elated or grandiose, but one-fourth had the cluster of symptoms with racing thoughts, pressured speech, and increased motor activity, and one-fourth had the paranoia-aggression-irritability cluster. Compared to patients with nonagitated depression, they had a longer time to 50% probability of recovery from the index episode, were more likely to receive standard antipsychotic drugs during that episode, and spent more time in an affective episode during the observation period.
Conclusions: The occurrence of agitated depression in bipolar I disorder is not rare and has significant prognostic and therapeutic implications. Whether the co-occurrence of a major depressive syndrome with one or two of these symptomatic clusters makes up a "mixed state" remains unclear.