An Open Label Pilot Study of Adjunctive Asenapine for the Treatment of Posttraumatic Stress Disorder

Inclusion Criteria: * Signed and dated informed consent and acceptable proof of identity. * Male or female subjects ≥19 to 65 years of age of any race or ethnic origin. * Not currently pregnant, breastfeeding or planning on becoming pregnant; use of contraception as follows: * Males - those that are sexually active must use a double barrier method of contraception (condom with spermicide) from the first dose of asenapine until 12 weeks after last dose of asenapine * Women of child-bearing potential - must have a negative urine pregnancy test and confirmed (by the investigator) use of a highly effective form of birth control for 3 months before enrollment and until 12 weeks after their last dose of asenapine. * Women of non-child bearing potential - women who are either permanently sterilized (hysterectomy, bilateral oophorectomy and bilateral salpingectomy but excluding bilateral tubal occlusion) or who are postmenopausal. * Diagnosis of PTSD (DSM-IV-TR criteria; confirmed by MINI and CAPS). * Total CAPS score \> 45. * Currently taking an approved antidepressant at acceptable dose for 8 weeks or more with non-remission of symptoms. * No substance use disorders of dependence (except for nicotine, caffeine) in previous 4 wks. * No substance use disorders of abuse (except for nicotine and caffeine) in the previous 2 wks. * Physical and laboratory panel (within past one year) are within normal limits or not clinically significant Exclusion Criteria: * Lifetime history of bipolar I, schizophrenia, schizoaffective or cognitive disorders (assessed by the MINI) * Actively considering plans of suicide or homicide (assessed by clinical interview) * Psychotic symptoms that in the investigator's opinion impair the subject's ability to give informed consent * A contraindication to the use of asenapine or antidepessant * Intolerable side effects or allergic reaction to asenapine or the current antidepressant * Women planning to become pregnant or breastfeed during the study * Clinically significant unstable or severe medical condition that would contraindicate study participation or expose them to an undue risk of a significant adverse event, including but not limited to: unstable or severe hepatic, renal, respiratory, cardiovascular, endocrine, neurologic, or hematologic disease; hypo- or hyperthyroidism, unless the condition has been stabilized; or a history of seizures (except for a single childhood febrile seizure, posttraumatic, or alcohol withdrawal). The following are exclusionary: platelets \< 75,000/mm; hemoglobin \<9g/dL; neutrophils, absolute \< 1000/mm; LFTs \> 3x upper limit; creatinine \> 2 mg/dL; diastolic BP \< 60 or \> 110mmHg; EKG QTc \> 475 msec. * In regard to vulnerable patient populations, persons with dementia, minors (\<age 19), the elderly (\>age 65), prisoners and the terminally ill are excluded.