Glial Regulators for Treating Comorbid Posttraumatic Stress and Substance Abuse Disorders

With the increased number of military veterans returning from conflicts in Afghanistan and Iraq diagnosed with posttraumatic stress disorder (PTSD), there is a high vulnerability of these individuals to develop a substance use disorder (SUD). While there have been a host of studies focused largely on dopaminergic mechanisms of drug reward, they have not led to the development of adequate treatments for either preventing people diagnosed with PTSD from developing SUD or for treating comorbid PTSD/SUD. Based on extensive work with addictive drugs and preliminary data from our group, the investigators propose that stress impairs prefrontal cortex regulation of the basal ganglia habit circuitry and this pathology renders PTSD patients susceptible to developing SUD. Moreover, the known effects of addictive drugs to further impair prefrontal regulation are synergistic with this pathology, thereby making treatment of comorbid PTSD/SUD particularly difficult. Preclinical studies have revealed that glutamate levels within the nucleus accumbens have been implicated in drug seeking behavior in the animal model of relapse. The amino acid precursor N-acetylcysteine (NAC) appears to restore glutamate to normal levels and may also prevent glutamate levels from spiking following subsequent stimulant use. The primary goal of the proposed study is to evaluate the efficacy and safety of N-acetylcysteine in preventing relapse in drug dependent individuals with PTSD or subthreshold PTSD. Veterans with substance use disorders who have achieved at lease one week of abstinence will be randomized to either placebo or NAC (2400-3600mg/day) for 8 weeks.