A systematic review of diffusion tensor imaging studies in affective disorders

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Affective disorders involve network dysfunction, with white matter abnormalities being a key component.
• Neuroimaging and histological techniques have previously identified white matter differences between affected individuals and controls.

Purpose of the Study:

• To systematically review diffusion tensor imaging (DTI) studies investigating white matter abnormalities in affective disorders.
• To synthesize findings on white matter integrity using DTI in subjects with affective disorders.

Main Methods:

• Systematic literature search of EMBASE and MEDLINE databases for DTI studies on affective disorders.
• Inclusion of 27 comparative studies and a meta-analysis of eight studies focusing on superior frontal regions.

Main Results:

• Twenty-one of 27 studies reported significantly lower white matter anisotropy in subjects with affective disorders versus controls.
• Reduced anisotropy was consistently observed in frontal and temporal lobes/tracts, with a large effect size in the superior frontal gyrus.
• Significant heterogeneity in methods and subject characteristics was noted across studies.

Conclusions:

• DTI studies consistently demonstrate reduced white matter anisotropy in the frontal and temporal regions of individuals with affective disorders.
• Despite methodological heterogeneity, DTI provides valuable insights into the neurobiological underpinnings of affective disorders.
• Findings support DTI as a crucial tool for understanding white matter alterations in affective disorders.