Longitudinal Neurocognitive Effects of Combined Electroconvulsive Therapy (ECT) and Pharmacotherapy in Major Depressive Disorder in Older Adults: Phase 2 of the PRIDE Study

Objective: There is limited information regarding neurocognitive outcomes of right unilateral ultrabrief pulse width electroconvulsive therapy (RUL-UB ECT) combined with pharmacotherapy in older adults with major depressive disorder. We report longitudinal neurocognitive outcomes from Phase 2 of the Prolonging Remission in Depressed Elderly (PRIDE) study. Method: After achieving remission with RUL-UB ECT and venlafaxine, older adults (≥60 years old) were randomized to receive symptom-titrated, algorithm-based longitudinal ECT (STABLE) plus pharmacotherapy (venlafaxine and lithium) or pharmacotherapy-only. A comprehensive neuropsychological battery was administered at baseline and throughout the 6-month treatment period. Statistical significance was defined as a p-value of less than 0.05 (two-sided test). Results: With the exception of processing speed, there was statistically significant improvement across most neurocognitive measures from baseline to 6-month follow-up. There were no significant differences between the two treatment groups at 6 months on measures of psychomotor processing speed, autobiographical memory consistency, short-term and long-term verbal memory, phonemic fluency, inhibition, and complex visual scanning and cognitive flexibility. Conclusion: To our knowledge, this is the first report of neurocognitive outcomes over a 6-month period of an acute course of RUL-UB ECT followed by one of 2 strategies to prolong remission in older adults with major depression. Neurocognitive outcome did not differ between STABLE plus pharmacotherapy versus pharmacotherapy alone over the 6-month continuation treatment phase. These findings support the safety of RUL-UB ECT in combination with pharmacotherapy in the prolonging of remission in late-life depression.