Elevated cortical glutamate in young people at increased familial risk of depression.
Taylor MJ., Mannie ZN., Norbury R., Near J., Cowen PJ.
Using proton magnetic resonance spectroscopy (MRS), we have demonstrated regional abnormalities in cortical γ-aminobutyric acid (GABA) and glutamate in medication-free recovered depressed patients. It is unclear whether these changes represent an underlying trait vulnerability to depression, or an after-effect of episodes of illness or its treatment. We sought to examine this question by examining a group of high-risk, never-depressed, individuals. We used MRS to measure GABA and glutamate in parieto-occipital cortex in young people (ages 16-21 yr) with a family history of parental depression (n=24) but no personal history of illness and a control group without a history of depression in any first-degree relative (n=28). Participants with a parental history of depression had significantly higher levels of glutamate than controls in parieto-occipital cortex (F₁,₄₇=5.5, p=0.02). These findings suggest that abnormalities in glutamate neurotransmission may reflect a trait marker of vulnerability to depression.