The use of complementary and alternative medicines (CAM) has increased among patients with psychiatric disorders over recent decades. Therefore, clinicians must inquire and be knowledgeable about the use of CAM therapies, not only to give their patients accurate and up-to-date information but also to know when to appropriately prescribe CAM therapies to patients. Of the available CAMs, omega-3 fatty acids, folate, SAM-e, and St John’s wort are reviewed.