The Relations Among Depression, Cognition, and Brain Volume in Professional Boxers: A Preliminary Examination Using Brief Clinical Measures.

Objective: Depression, neuropathology, and cognitive decline are commonly observed with repetitive head injuries (RHIs). We examined whether in boxers (a) clinically significant depression is associated with structural brain changes and cognition; (b) minimal symptoms of depression moderate the relations among RHI and brain volumes and cognition; and (c) baseline depression is associated with longitudinal cognitive changes.

Setting: Clinical Research Center.

Participants: A total of 205 male professional boxers.

Design: Cross-sectional and longitudinal (subsample: n = 45; first visit to follow-up range = 1-6 years; mean = 2.61 years).

Main Measures: Patient Health Questionnaire-9 depression; CNS Vital Signs cognitive battery; brain imaging.

Results: Clinically significant depression was associated with smaller regional volumes in insula, cingulate, orbitofrontal cortex, thalami, and middle corpus-callosum subregions; and with poorer verbal memory and psychomotor speed performance. Depression symptoms moderated the relations between RHI and bilateral thalami, left hippocampus, left medial orbitofrontal cortex, and bilateral insula volumes; but not cognition. Baseline depression was associated with poorer psychomotor speed and reaction time longitudinally and improved verbal memory performance longitudinally.

Conclusion: Clinical depression is associated with volumetric and cognitive changes occasioning RHI exposure, and even minimal depressive symptoms may moderate the relations between exposure and brain volumes in key regions. Longitudinally, there is preliminary evidence that depression precedes cognitive changes.