Diagnostic Criteria for Depression in Alzheimer Disease: A Study of Symptom Patterns Using Latent Class Analysis

Context: Although depression in Alzheimer disease (AD) has a negative emotional and functional impact on patients and caregivers, specific criteria to diagnose depression in AD are still to be validated. Objective: To validate a set of diagnostic criteria for major depression in AD. Design: Cross-sectional design using latent cluster analysis (LCA). Setting: Participants were recruited from consecutive referrals to a Memory Clinic of a tertiary hospital. Participants: A consecutive series of 971 outpatients with probable AD. Main Outcome Measure: Clusters of patients with or without major depression as determined with LCA. Results: A LCA demonstrated three clusters that were considered to represent major depression, minor depression, and no depression. All nine Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for major depression were significantly associated with the major depression cluster. Although a diagnosis of generalized anxiety disorder (GAD) and apathy were also associated with the major depression cluster, irritability was not. Conclusions: The DSM-IV criteria for major depression should be used unmodified to diagnose depression in AD. Future studies should determine whether GAD should be included as an additional diagnostic criterion. (Am J Geriatr Psychiatry 2011; 19:551-558)