The Effect of NK1R Antagonism on Alcohol Craving and PTSD Symptoms in Alcohol Dependent Patients With PTSD

Objective: Alcoholism is highly co-morbid with post traumatic stress disorder (PTSD). Since stress and negative affective states are major relapse triggering factors for alcohol use, the negative symptoms associated with PTSD are thought to promote alcohol dependence. Substance P, which is released in the amygdala in response to stress, acts at NK1 receptors (NK1Rs) to mediate behavioral stress responses. Blockade of the NK1R represents a novel approach for anti-stress actions. In a recent double blind, placebo controlled study involving detoxified anxious alcoholics, we found that NK1R antagonism decreased alcohol cravings, attenuated cortisol response to stress, and significantly decreased insula activation in response to negative sensory input. The present study is intended to expand the findings and determine whether the NK1R is a candidate target for treating alcohol dependent patients with PTSD. Study Population: On hundred twenty participants with PTSD and co-morbid alcohol dependence will be recruited and stratified by PTSD etiology (60 participants each with civilian and combat PTSD, resp). Within each stratum, the treatment groups will be balanced for sex using urn randomization. Stratification is indicated since civilian and combat-related PTSD can theoretically have a different pathophysiology. Civilians typically experience a single trauma exposure of invariably high magnitude, resulting in symptoms immediately. Combat-related PTSD typically results from multiple traumatic exposures over a prolonged period of time, of variable magnitude, and frequently with delayed emergence of symptoms. Design: Participants will be admitted to the NlAAA research inpatient unit at the NIH Clinical Research Center (CRC) under protocol number 05-AA-0121 for assessment and treatment of people with alcohol drinking problems, which provides diagnostic assessments and standard withdrawal treatment if needed. Participants will enter into the present protocol once such treatment, if needed, is completed. Following inclusion, all participants will receive 1 week of single blind placebo, and will then be randomized to double blind treatment with aprepitant or placebo. Randomized treatment will be for approximately 3 weeks. Spontaneous cravings for alcohol, and ratings of psychopathology will be obtained twice weekly on the inpatient unit throughout the study. Cravings as well as endocrine and immune responses will also be assessed in a challenge session that combines a social stressor and exposure to physical alcohol cues. During the final week, three sessions utilizing scripts will be carried out, on separate days in counter-balanced order, exposing the participant to personalized trauma, alcohol associated or neutral stimuli. Cravings as well as endocrine and immune responses will also be assessed during the script presentations. An fMRI session will be carried out during week 4 to assess responses to affective stimuli. Participants will remain hospitalized throughout the study, and will remain on the unit for a three day post-medication monitoring period. Outcome Measures: The primary outcome will be change in craving for alcohol and changes in PTSD symptoms resulting from the script sessions. Secondary outcomes will include cravings and changes in PTSD symptoms resulting from the combined social stress-alcohol cue challenge session, spontaneous craving and PTSD symptoms during hospitalization, and brain responses on the fMRI session. Changes in PTSD symptoms and change in craving for alcohol are intended to be surrogate markers for the overall effect of the drug treatment and are not intended to represent global improvement for either PTSD or alcoholism.