Impulsivity is a central feature of addiction. Nalmefen is an authorized treatment for alcohol addiction. Baclofen has empathically been advocated to have some efficacy in this indication. The aim of the present study is to test the effect of Nalmefene and Baclofen on impulsivity.

Primary study objective: To examine the effect of Nalmefene and Baclofen on impulsivity (as measured by the Stop Signal Task) in subjects with alcohol use disorder and healthy control subjects.

Main secondary study objectives: To examine the effect of Nalmefene and Baclofen on risk taking (as measured by the Balloon Analogue Risk Task) and on the preference for small immediate rewards over large delayed rewards (as measured by the Delay Discounting Task). To compare subjects with alcohol use disorder and healthy control subjects on these tasks.

Primary study outcome: Stop-signal reaction time in the Stop-Signal Task Main secondary study outcomes: Equivalence point in the Delay-Discounting Task and Average number of pumps delivered in the Balloon Analogue Risk Task

Study Design: Randomized, placebo control, cross-over, single-dose

Inclusion Criteria:

• 30 patients with DSM-5 Diagnosis of Alcohol Use Disorder, at least moderate (303.90/F10.20),
• 30 sex and age-matched healthy controls,
• over 18, informed consent.

Exclusion Criteria:

• opiate-treatment,
• contra-indications for Nalmefene and/or Baclofen,
• unstable psychiatric disorder,
• pregnancy,
• acute withdrawal syndrome.