CADASIL, cerebral autosomal dominant arteriopathy with subcortical infarcts and leuko encephalo - pathy, is a rare hereditary disease characterized by recurrent transient ischemic attacks (TIA), strokes, and vascular dementia. It was first described in 1991 by Tourmier-Lasserve. The causative factor of CADASIL is mutations of the Notch3 gene located on chromosome 19. About 400 families have been diagnosed so far. Its clinical manifestations appear for the first time between 30 and 50 years of age and include attacks of migraine with aura, recurrent ischemic subcortical events, subcortical dementia and psychiatric disturbances varying from anxiety to severe depression, even psychotic disorders. Due to the rare incidence of CADASIL, many cases are still misdiagnosed or undiagnosed and are treated as ordinary psychiatric patients. The existing evidence implies that psychiatric disturbances and CADASIL co-occur so the possibility of a patient suffering from CADASIL should be considered in any individual having mental illness and a suggestive family history. This parer describes the psychiatric approach on a patient presenting anxiety, depression and a family history of CADASIL, who faces the dilemma of being diagnosed with CADASIL.