The research project has been cancelled before any participants were enrolled.

It has been suggested that N-acetylcysteine exerts neuroprotective effects by regulating neurotransmitters and cell signaling pathways. We hypothesize that oral N-acetylcysteine augmentation will help reduce symptoms in patients with posttraumatic stress disorder as well as improve cognitive functions. We also expect that the N-acetylcysteine augmentation will induce change in structural, functional, and neurochemical aspects of the brain.

In this study, we plan to conduct a randomized, double-blind, placebo-controlled augmentation study with N-acetylcysteine in addition to escitalopram. We will assess the efficacy and safety of the N-acetylcysteine augmentation.

Inclusion Criteria:

• 20-65 year-old male or female
• Posttraumatic stress disorder diagnosed by SCID-IV
• Written informed consent

Exclusion Criteria:

• Medication treatment for posttraumatic stress disorder within 2 weeks
• Neurologic disease (eg., penetrating or open head injury, epilepsy, multiple sclerosis, brain tumor, cerebrovascular diseases)
• Any other axis I psychiatric disorder
• IQ below 80
• Contraindications to magnetic resosnance imaging (e.g., pacemaker implantation, claustrophobia, etc.)
• Any psychotropic medication within 2 weeks
• Unstable medical illness or severe abnormality in laboratory test at screening assessment
• Women who are pregnant, breastfeeding, or planning pregnancy
• History of myocardial infarction within 6 months
• Current diagnosis of duodenal ulcer or asthma
• Contraindications to drugs used in the study (e.g., epilepsy, uncontrolled narrow-angle glaucoma, etc.)
• Allergy or intolerance to the study drug