The selective serotonin reuptake inhibitors have become a first line treatment 
for post-traumatic stress disorder (PTSD). In a recent double-blind study in 
civilians, fluoxetine produced clinically and statistically significant effects 
on all general measures of PTSD. We examined the specific effects of fluoxetine 
versus placebo in the above mentioned study of PTSD clusters and individual 
symptoms. Individuals were included if they met criteria for PTSD according to 
the Structured Clinical Interview for DSM-III-R (SCID). Symptoms were assessed 
at sequential time points by the Structured Interview for PTSD (SIP), a 
clinician interview based assessment, and a self-report scale, the Davidson 
Trauma Scale (DTS). A total of 53 patients were included in the analysis. On the 
SIP and DTS, fluoxetine was found to produce statistically significant changes 
on all clusters. Significant effects for fluoxetine were noted on 10 items of 
the DTS, and 8 items of the SIP. The SIP and DTS had 6 items in common that were 
significant. Fluoxetine exerts a broad spectrum effect in reducing all the 
symptom clusters of PTSD in this sample. The symptoms of being physically upset 
at reminders of the trauma, avoiding thoughts of the trauma, having difficulty 
enjoying things, feeling distant/estranged, having a sense of foreshortened 
future, and impaired concentration, were the symptoms most responsive to the 
effects of treatment with fluoxetine on both scales.