The therapeutic effects of valproate in psychiatric conditions are most substantially recognized in bipolar disorder. However, this well-tolerated medication may be beneficial in the treatment of other mental illnesses. In this article, the authors comprehensively review studies of valproate as treatment for psychiatric conditions, including bipolar, depressive, anxiety, and psychotic disorders; alcohol withdrawal and dependence; tardive dyskinesia; agitation associated with dementia; and borderline personality disorder. Valproate shows the most promising efficacy in treating mood and anxiety disorders, with possible efficacy in the treatment of agitation and impulsive aggression, and less convincing therapeutic response in treating psychosis and alcohol withdrawal or dependence. The authors conclude with a brief summary of its mechanism of action and therapeutic spectrum.