Risperidone Augmentation for PTSD

Inclusion Criteria: * Signed consent prior to any study procedures being done * Male or female outpatients between 18-65 years of age * Trauma experienced meets trauma defined by DSM * Meets criteria for DSM-IV PTSD as a result of civilian trauma * CAPS Score of greater than or equal to 50 at screening and baseline * Able to swallow whole capsules * Fluency in both written and spoken English * Negative urine drug screen at screening visit * If female of childbearing potential, must have negative serum pregnancy test at screening visit and must agree to use a medically accepted means of contraception throughout the study and for 30 days after completion of the study * To be include in Phase 2, must complete Phase I and must have less than 70% reduction from baseline on the CAPS Exclusion Criteria: * Pregnant women or those likely to become pregnant, or nursing mothers * Medical instability (clinically significant hepatic, cardiac, or pulmonary disease, HIV, uncontrolled hypertension, diabetes or thyroid conditions, seizure disorders, clinically significant laboratory abnormalities at screen * Primary psychotic disorder, or history of schizophrenia, other psychotic disorder, bipolar disorder, or cognitive disorder * Those considered a risk for suicidal or homicidal behavior (the clinician will immediately, upon assessing a risk for suicidal or homicidal behavior, refer the patient for further evaluation and probable hospitalization) * Hypersensitivity or other contraindication to sertraline or risperidone * Meeting DSM-IV criteria for drug or alcohol dependence within 3 months of study entry * Those who are still experiencing an ongoing traumatic stressor (domestic violence/elder abuse) who will need to focus on safety (the clinician will make referrals as appropriate) * DSM-IV primary diagnosis of any other anxiety disorder or major depressive disorder * Current use of antipsychotic, or other psychotropic medications, or supplements with known psychotropic effects * Current involvement in litigation related to PTSD * Current psychotherapy aimed at treating PTSD * PTSD as a result of combat-related trauma * Previous failure to respond to sertraline-risperidone combination at therapeutic dose