Background: Abnormalities in the prefrontal cortex have been implicated in the pathogenesis of major depressive disorder (MDD). To our knowledge, no prior study has examined prefrontal cortical anatomy in pediatric patients with MDD near the onset of illness before receiving treatment.
Methods: Volumetric magnetic resonance imaging studies were conducted in 22 psychotropic-naive patients with MDD, aged 9 to 17 years (10 males and 12 females), and 22 case-matched healthy comparison control subjects. Twelve of the 22 patients with MDD had at least 1 first-degree relative with MDD (familial MDD), whereas 10 had no clear family history of MDD (nonfamilial MDD).
Results: Patients with nonfamilial MDD had significantly larger left-sided but not right-sided prefrontal cortical volumes than patients with familial MDD (17% larger) and controls (11% larger). Left-sided and right-sided prefrontal cortical volumes did not differ significantly between patients with familial MDD and controls.
Conclusions: These results provide new evidence of prefrontal cortical alterations in pediatric MDD that may differ in familial and nonfamilial subtypes of MDD. Our findings must be considered preliminary, however, in view of the small sample size.