Isotretinoin, an active form of vitamin A, is the drug of last resort for the treatment of severe acne. Depression, suicidal ideation, and psychosis are among the most well-documented psychiatric side effects. Here, we report a case of isotretinoin-induced psychosis, which was diagnosed as delusional disorder somatic subtype, in a young male in the absence of any prodromal symptoms, previous psychiatric history, or family history of mental illness. The onset of psychosis was in the context of a dosage increase from 40 mg/day to 80 mg/day. Isotretinoin was discontinued, and the patient showed improvement on low-dose quetiapine.