A Pilot Study to Assess the Effects of Doxazosin on Polysomnography in PTSD

Inclusion Criteria: 1. Age 18-69 2. Current full or partial syndromal PTSD of at least 3 months duration as indexed by the CAPS (Clinician-administered PTSD scale) score \>30 3. CAPS recurrent distressing dreams item of \>/= 5 Exclusion Criteria: 1. alcohol and or drug abuse/dependence in the last 3 months 2. lifetime history of any psychiatric disorder with psychotic features, bipolar disorder, obsessive-compulsive disorder 3. exposure to trauma within the last 3 months 4. prominent suicidal or homicidal ideation 5. sleep apnea diagnosis or positive screen for sleep apnea by Type III device. 6. neurologic disorder or systemic illness affecting CNS function 7. history of brain trauma or head injury with loss of consciousness greater than 10 minutes 8. chronic or unstable medical illness including unstable angina, myocardial infarction within the past 6 months, congestive heart failure, preexisting hypotension or orthostatic hypotension, chronic renal or hepatic failure, and pancreatitis 9. pregnancy, breastfeeding and/or refusal to use effective birth control 10. previous serious adverse reaction to an alpha-1-antagonist (such as priapism, hepatitis, angioedema, or intraoperative floppy iris syndrome) 11. current use of trazodone, hypnotics/benzodiazepines, mirtazapine, atypical antipsychotics, beta-adrenergic blockers, alpha-2-agonists, and current prazosin or other alpha-1-antagonists 12. previous non-response to prazosin for treatment of PTSD related sleep disturbance Participants taking SSRIs, bupropion, venlafaxine and duloxetine may be included if they have been on a stable dose for 2 months. Participants may be included if they have been stable in psychotherapy treatment for 2 months and/or if they begin no new psychotherapy while in the trial.