APOE and major depressive disorder: Our results are convergent with those observed in a population-based study by Burke et al.3 where, in a sample of more than 11,000 cognitively intact participants, delusions, hallucinations, agitation, depression, anxiety, elation apathy, disinhibition, irritability, motor disturbances, appetite, and sleep disturbances appeared to have additive interactions with APOE ε4 as risk factors for dementia conversion.