OBJECTIVES~The first objective of the current study is to examine norepinephrine alpha1 (NE-alpha1) receptor involvement in reactivity to unpredictable stressors in humans, by using the NPU stress task in conjunction with an alpha1-blocker, prazosin. The second objective of the study is to provide preliminary evidence that prazosin is effective at reducing stress-reactivity in alcoholics in early abstinence.~PARTICIPANTS~Sixty-four healthy adult participants and sixty-four participants with an Alcohol Use Disorder in early abstinence.~STUDY OVERVIEW~Sixty-four healthy adult participants (32 males & 32 females) will be recruited to participate in a double-blind, placebo-controlled, cross-over design study examining the effects of a NE-alpha1 antagonist (prazosin) on the defensive (physiological and self-report affect) response to stressors using a well-validated animal-human translational stressor task. Participants will complete two overnight study visits where 2 mg prazosin and placebo are administered on separate visits separated by approximately 7 days. Drug order is randomly assigned and counterbalanced across participants (double-blind; study visits 1-2). On each of these two study visits, participants will complete the No Shock, Predictable Shock, Unpredictable Shock (NPU) task 90 minutes after drug administration. The NPU task is designed to examine stress reactivity to predictable and unpredictable stressors (i.e., electric shock). These two visits provide for a within-subject evaluation of the effect of acute antagonism of alpha1-NE receptors (via prazosin) to investigate the role of this NE mechanism in unpredictable (vs. predictable) stressor response.~After the full healthy adult/control sample has completed the study, the investigators will conduct preliminary data analysis to evaluate the first study hypothesis. These analyses are used to evaluate the sensitivity of the NPU task to NE-alpha1 mechanisms and its potential utility as an early surrogate endpoint for stress-related relapse mechanisms in alcoholism. The investigators will only recruit the sample of sixty-four alcoholic participants to complete the study if the first hypothesis is initially supported with healthy controls. These participants will meet Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) criteria for Alcohol Use Disorder (at least moderate severity) and be in early abstinence (1-8 weeks). All other study procedures will be identical for this sample.~OUTCOME MEASURES~The primary outcome is startle potentiation during the NPU task and the secondary outcome is self-reported retrospective fear/anxiety during the NPU task.~HYPOTHESES~Prazosin (2mg vs. placebo) will reduce stress reactivity to unpredictable (vs. predictable) stressors measured via startle potentiation and self-report.~Abstinent alcoholics (vs. controls) will display elevated stress reactivity to unpredictable (vs. predictable) stressors measured via startle potentiation and self-report.~The predicted effects of prazosin on reducing stress reactivity to unpredictable (vs. predictable) stressors (Hypothesis 1) measured via startle potentiation and self-report will be moderated by alcoholism, such that the effects of prazosin will be larger in abstinent alcoholics than control participants.
Double-blind, placebo-controlled, cross-over design study examining the effects of a norepinephrine alpha1 receptor antagonist (prazosin) on stress reactivity in a laboratory stressor task.