Dopaminergic pathways are implicated in motivational aspects of substance use disorders, and might contribute to withdrawal phenomena, as well as an increased long-term risk of relapse. Molecular imaging with positron emission tomography (PET) revealed reductions in the availability of binding sites for D2/3receptor ligands in striatum of withdrawn abusers of cocaine; corresponding results in alcoholics have been inconsistent so far. In the present study, we used the D2/3ligand [18F]fallypride to investigate dynamic changes in receptor availability in the striatum of patients with alcohol use disorder before and after undergoing a detoxification protocol.

18 male patients (mean age 44±5.3y) with alcohol use disorder were recruited and scanned with 180MBq [18F]fallypride upon hospital admission, and again 1-2 weeks later after detoxification. The control group consisted of 10 age-matched healthy volunteers. PET acquisition time was 180min, consisting of 39 frames of increasing duration. Within each group binding potentials (BPND) were calculated in the striatum using the cerebellum as reference.

In the patients, the mean BPND in whole striatum was 17.2±4.2 at baseline, with a trend towards a decline at follow-up. In addition there were inverse correlations of BPNDwith age (r-0.45) and with daily alcohol consumption (r-0.2). The age-dependence of BPNDwas less pronounced in healthy controls. However, mean striatal BPNDwas only slightly lower in the patient group. No pronounced group differences were evident for extrastriatal [18F]fallypride binding.

Regressions with age suggest an accelerated loss of dopamine D2/3 receptors in the striatum of subjects with alcohol use disorder.