Single photon emission computed tomography in posttraumatic stress disorder before and after treatment with a selective serotonin reuptake inhibitor.
BACKGROUND
Posttraumatic stress disorder (PTSD) is recognized as a disorder mediated by specific neurobiological circuits. Functional imaging studies using script-driven trauma imagery and pharmacological challenges have documented altered cerebral function (activation and deactivation) in several brain regions, including the amygdala, hippocampus, prefrontal cortex and anterior cingulate. However, the neural substrates of PTSD remain poorly understood and the effect of selective serotonin reuptake inhibition on regional cerebral activity is deserving of further investigation.


METHODS
Eleven adult patients (seven men, four women) (mean age+S.D.=33.6+/-9.2 years) with a DSM-IV diagnosis of PTSD, as determined by the Structured Clinical Interview for DSM-IV (SCID-I) and the Clinician-Administered PTSD Scale (CAPS), underwent single photon emission computed tomography (SPECT) with Tc-99m HMPAO pre- and post-8 weeks of treatment with the selective serotonin reuptake inhibitor, citalopram. Symptoms were assessed at baseline and at 2-week intervals with the Clinician-Administered PTSD Scale (CAPS), Montgomery-Asberg Depression Rating Scale (MADRS), and the Clinical Global Impression Scale (CGI). Image analysis of baseline and post-treatment scans was performed using Statistical Parametric Mapping (SPM).


RESULTS
Treatment with citalopram resulted in significant deactivation in the left medial temporal cortex irrespective of clinical response. On covariate analysis, a significant correlation between CAPS score reduction and activation in the left paracingulate region (medial prefrontal cortex) was observed post-treatment. No significant pre-treatment differences were observed between responders and non-responders in anterior cingulate perfusion.


CONCLUSIONS
These preliminary findings are consistent with clinical data indicating temporal and prefrontal cortical dysfunction in PTSD and preclinical data demonstrating serotonergic innervation of these regions. However, further studies, in particular in vivo receptor imaging studies, are needed to confirm whether these regional abnormalities correlate with clinical features and treatment response.
Seedat
Soraya
S
Department of Psychiatry, University of Stellenbosch, Tygerberg, 7505, Cape Town, South Africa. sseedat@sun.ac.za
Warwick
James
J
van Heerden
Barend
B
Hugo
Charmaine
C
Zungu-Dirwayi
Nompumelelo
N
Van Kradenburg
Jeanine
J
Stein
Dan J
DJ
D000328:Adult; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000187:drug effects; D015283:Citalopram / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006179:Gyrus Cinguli / Q000098:blood supply / Q000000981:diagnostic imaging / Q000187:drug effects; D006801:Humans; D008297:Male; D017397:Prefrontal Cortex / Q000098:blood supply / Q000000981:diagnostic imaging / Q000187:drug effects; D011569:Psychiatric Status Rating Scales; D012039:Regional Blood Flow / Q000187:drug effects; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D013313:Stress Disorders, Post-Traumatic / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000503:physiopathology; D019690:Technetium Tc 99m Exametazime; D013702:Temporal Lobe / Q000098:blood supply / Q000000981:diagnostic imaging / Q000187:drug effects; D015899:Tomography, Emission-Computed, Single-Photon; D016896:Treatment Outcome
D015283:Citalopram; D017367:Selective Serotonin Reuptake Inhibitors; D019690:Technetium Tc 99m Exametazime