Reduced in vivo visual cortex GABA in schizophrenia, a replication in a recent onset sample

Area of Science:

• Neuroscience
• Psychiatry
• Neuroimaging

Background:

• The gamma-aminobutyric acid (GABA) deficit hypothesis is a leading explanation for schizophrenia's information processing deficits.
• Previous in vivo studies on GABA in schizophrenia have produced inconsistent findings, often relying on post-mortem data.

Purpose of the Study:

• To replicate findings of reduced early visual cortex GABA in recent-onset schizophrenia using in vivo magnetic resonance spectroscopy (MRS).
• To investigate whether antipsychotic treatment confounds GABA level measurements in schizophrenia.

Main Methods:

• Single voxel proton magnetic resonance spectroscopy (MRS) with a MEGA-PRESS sequence was used on a 3T MR scanner.
• GABA concentration was measured in the early visual cortex of 23 recent-onset schizophrenia patients and 31 healthy controls.
• Head movement during scans was quantified and excessive movement was excluded to control for motion artifacts.

Main Results:

• Patients with recent-onset schizophrenia exhibited significantly lower GABA levels in the early visual cortex compared to healthy controls (p=0.029).
• No significant difference in GABA levels was observed between antipsychotic-naïve patients and those treated with antipsychotics.

Conclusions:

• Reduced GABA levels in the visual cortex are a reliable finding in schizophrenia, evident even in the early stages of the illness.
• Illness chronicity and antipsychotic medication do not appear to confound these GABA level reductions in the visual cortex.