There are forms of Alzheimer's disease (AD) that have an autosomal dominant inheritance pattern; one of them is caused by the E280A mutation in the gene that codes for Presenilin-1 (PSEN1). Studying families of people with this mutation allows the evaluation of characteristics of the subjects before cognitive decline begins. To determine whether having the mutation E280A in PSEN1 increases the risk of presenting mental disorders in adults under 30 years old who are in the preclinical stage of AD and may be eligible for primary prevention studies of AD. A psychiatric evaluation was made to 120 people belonging to families with a history of early onset AD. Of these, 62 carried the E280A mutation in PSEN1. The occurrence of mental disorders between carriers and non-carriers of the mutation was compared. No statistically significant differences were found in the frequency of any mental disorder between the group of carriers and non-carriers of the mutation (Hazard Ratio: 0.80, 95% CI 0.49 to 1.31); nor were differences observed when evaluating specific disorders. The E280A mutation does not increase the risk of mental disorders before the age of 30 in the relatives of people affected by familial AD. Studies with larger sample sizes are required to assess the risk of low incidence mental disorders.