Format

Send to

Choose Destination
Sleep. 2014 May 1;37(5):893-900. doi: 10.5665/sleep.3654.

Cortical gamma-aminobutyric acid and glutamate in posttraumatic stress disorder and their relationships to self-reported sleep quality.

Author information

1
Department of Radiology and Biomedical Imaging, Center for Imaging of Neurodegenerative Diseases, DVA Medical Center, and University of California San Francisco, San Francisco, CA.
2
Psychiatry Research Service VAMC, and University of California San Francisco, San Francisco, CA.

Abstract

STUDY OBJECTIVES:

To test if posttraumatic stress disorder (PTSD) is associated with low brain gamma-aminobutyric acid (GABA) levels and if reduced GABA is mediated by poor sleep quality.

DESIGN:

Laboratory study using in vivo proton magnetic resonance spectroscopy (1H MRS) and behavioral testing.

SETTING:

VA Medical Center Research Service, Psychiatry and Radiology.

PATIENTS OR PARTICIPANTS:

Twenty-seven patients with PTSD (PTSD+) and 18 trauma-exposed controls without PTSD (PTSD-), recruited from United States Army reservists, Army National Guard, and mental health clinics.

INTERVENTIONS:

None.

MEASUREMENTS AND RESULTS:

1H MRS at 4 Tesla yielded spectra from three cortical brain regions. In parieto-occipital and temporal cortices, PTSD+ had lower GABA concentrations than PTSD-. As expected, PTSD+ had higher depressive and anxiety symptom scores and a higher Insomnia Severity Index (ISI) score. Higher ISI correlated with lower GABA and higher glutamate levels in parieto-occipital cortex and tended to correlate with lower GABA in the anterior cingulate. The relationship between parieto-occipital GABA and PTSD diagnosis was fully mediated through insomnia severity. Lower N-acetylaspartate and glutamate concentrations in the anterior cingulate cortex correlated with higher arousal scores, whereas depressive and anxiety symptoms did generally not influence metabolite concentrations.

CONCLUSIONS:

Low brain gamma-aminobutyric acid (GABA) concentration in posttraumatic stress disorder (PTSD) is consistent with most findings in panic and social anxiety disorders. Low GABA associated with poor sleep quality is consistent with the hyperarousal theory of both primary insomnia and PTSD. Our data demonstrate that poor sleep quality mediates low parieto-occipital GABA in PTSD. The findings have implications for PTSD treatment approaches.

KEYWORDS:

GABA; brain; glutamate; magnetic resonance spectroscopy; posttraumatic stress disorder; sleep

PMID:
24790267
PMCID:
PMC3985106
DOI:
10.5665/sleep.3654
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center