Quetiapine Treatment for Post-Traumatic Stress Disorder (PTSD)

Inclusion Criteria: * Male or female patients 18 years of age or older of any ethnic background meeting Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for PTSD. * Score of at least 50 on the CAPS-SX at baseline. * Competent to give informed consent. * If female, patient should be using a medically approved contraceptive, or not otherwise be of childbearing potential. * Patients who have not taken medications or herbal remedies for a psychiatric indication within one week prior to the randomized phase. * Other medications, if any, must have been kept stable for at least one month prior to randomization. Exclusion Criteria: * History of sensitivity to quetiapine * Use of antipsychotics, antidepressants, or benzodiazepines (except for short-term use during study as specified in Concomitant Medications section) within one week prior to randomization and throughout the study period. * Medical conditions that may prevent safe administration of quetiapine including clinically significant hepatic, cardiac, or pulmonary disease. * Medical disorders that may cause or exacerbate anxiety symptoms. * Alcohol or drug abuse or dependence within one month of study entry as defined by DSM-IV criteria. * Schizophrenia, schizoaffective disorder, or bipolar disorder. * Suicidal or homicidal ideation or other clinically significant dangerousness * Currently seeking compensation or increase in compensation for the effects of the trauma. * Initiation or change in psychotherapy within 3 months of randomization.