Despite affecting over half the world’s population for up to 10 years of each individual’s life, perimenopause is an understudied, underrecognized, and undertreated condition with profound effects on physical and psychological health. The evidence that does exist suggests that perimenopause is a high-risk time for both new-onset and exacerbation of multiple mental health conditions, including depression and psychosis. This training will review the dominant theories behind these worsening mental health symptoms, how to approach the differential diagnosis, and a range of treatment options for mood and anxiety symptoms during perimenopause. The goal is for providers managing perinatal patients with mental health challenges to gain knowledge and confidence to better help navigate treatment choices.