Smaller brain size likely in young adults (<40 years old) with depressive symptoms compared to healthy controls: a retrospective study.

PURPOSE

The aim of this study was to determine whether the brain size of young patients with depressive symptoms is smaller than that of healthy controls using magnetic resonance imaging (MRI).

MATERIALS AND METHODS

We retrospectively evaluated brain size by calculating the ratio of the brain area to that of the skull (the brain-to-skull ratio) on routine MRI scans including the splenium of the corpus callosum obtained from 19 patients <40 years old with depressive symptoms in 2009. The controls were 12 healthy individuals <40 years old who underwent MRI for medical examinations.

RESULTS

The mean brain-to-skull ratio of the control group was 0.850 ± 0.022 (range 0.822-0.889), and that of the patient group was 0.819 ± 0.041 (range 0.756-0.878). An unpaired t-test showed a significant difference in the brain-to-skull ratios between these groups (P = 0.011). In particular, in 7 of the 19 patients with longer duration of illness and more severe symptoms, the brainto-skull ratio was 89%-92% of the mean ratio of the control group.

CONCLUSION

The brain size of young patients with depressive symptoms appears to be smaller than that of healthy controls.