Rapid cycling bipolar disorder after left temporal polar damage.

The case of a 48-year-old woman with rapid cycling bipolar disorder subsequent to a traumatic brain injury is reported. Both depressive and manic episodes had an average duration of approximately 1 month, alternating without stable euthymic periods. Neuroradiological examinations revealed a circumscribed lesion in the left temporal pole. After 1 year without treatment, psychiatric intervention and pharmacotherapy was initiated. Her mood swings were successfully treated with the co-administration of valproate and lithium. Case reports of rapid cycling bipolar disorder after traumatic brain injury are very rare and this case supports the idea that temporal polar dysfunction is a candidate for the neurobiological basis of rapid cycling bipolar disorder.