Purpose: First-degree relatives of patients with bipolar disorder (BD) or major depressive disorder (MDD) are at risk of developing a major psychiatric disorder. However, preventive studies using pharmacological treatment of this high-risk group are sparse. The present study undertakes a scoping review to evaluate the literature of pharmacological treatment of individuals at familial risk of BP or MDD. Recent findings: Previous reviews on the pharmacological treatment of first-degree relatives at risk of BD, primarily investigates high-risk participants who were offspring of parents with BD and to our knowledge have not included individuals at risk of MDD, although it is well-known that there is a genetic overlap between BD and MDD. Summary: Nine studies comprising 299 high-risk individuals, mainly adolescents, were included. Aripiprazole, lithium, paroxetine, divalproex, quetiapine, lamictal, and escitalopram were investigated. One study only detected a positive effect, reducing mania symptoms, a study on aripiprazole vs placebo. Five planned or ongoing studies were identified. Only one study is still recruiting and the others either terminated due to recruitment difficulties or passed their marked completion date. Recruitment difficulties seem to be a major challenge; however, adult individuals at high risk are not well investigated and would presumably be easier to recruit. It is not clear if pharmacological interventions may prevent the onset of mood disorders, and further research is warranted.