Can brain-imaging studies provide a 'mood stabilizer signature?'

Area of Science:

• Neuroimaging
• Psychiatry
• Neurobiology

Background:

• Bipolar disorder is characterized by mood disturbances.
• Neurobiological underpinnings of bipolar disorder are being investigated using brain imaging.
• Treatment response in bipolar disorder is a critical area of research.

Purpose of the Study:

• To review in vivo brain-imaging studies examining neurobiological correlates of treatment response in bipolar disorder.
• To identify gaps in the characterization of brain correlates for mood stabilizer treatment response.

Main Methods:

• A MEDLINE literature search was conducted for in vivo brain-imaging studies.
• Studies focused on neurobiological correlates of treatment response in mood disorder patients.
• Selected studies examined anatomical, functional, and neurochemical brain alterations.

Main Results:

• Bipolar patients exhibit anatomical abnormalities in the prefrontal cortex, medial temporal lobe, and cerebellum.
• Functional imaging suggests abnormalities in brain circuits involving these regions and the striatum.
• Neurochemical studies indicate reduced N-acetyl aspartate and altered phospholipids in frontal and temporal lobes.

Conclusions:

• Available evidence points to widespread anatomical, neurochemical, and functional brain abnormalities in bipolar disorder.
• Preliminary findings suggest lithium may have neurotrophic effects, increasing gray matter and N-acetyl aspartate.
• In vivo brain correlates of treatment response to mood stabilizers in bipolar disorder are not yet well characterized.