Late-onset major depression: clinical and treatment-response variability.

Objective: To explore clinical and treatment-response variability in late-onset vs early-onset non-bipolar, non-psychotic major depression.

Methods: We grouped patients from a late-life depression treatment study according to illness-course characteristics: those with early-onset, recurrent depression (n = 59), late-onset, recurrent depression (n = 27), and late-onset, single-episode depression (n = 95). Early-onset was defined as having a first lifetime episode of major depression at age 59 or earlier; late-onset was defined as having a first episode of major depression at age 60 or later. We characterized the three groups of patients with respect to baseline demographic, neuropsychological, and clinical characteristics, use of augmentation pharmacotherapy to achieve response, and treatment outcomes.

Results: Rates of response, remission, relapse, and termination were similar in all three groups; however, patients with late-onset, recurrent major depression took longer to respond to treatment than those with late-onset, single-episode depression (12 weeks vs 8 weeks) and had more cognitive and functional impairment. Additionally, patients with recurrent depression (whether early or late) were more likely to require pharmacotherapy augmentation to achieve response than patients with a single lifetime episode.

Conclusion: Late-onset, recurrent depression takes longer to respond to treatment than late-onset single-episode depression and is more strongly associated with cognitive and functional impairment. Further study of biological, neuropsychologic, and psychosocial correlates of late-onset, recurrent depression is needed.