Occupancy of dopamine D2 receptors by antipsychotic drugs is related to nicotine addiction in young patients with schizophrenia.
BACKGROUND
Occupancy of dopamine D2 receptors by antipsychotic drugs depends on the individual availability of D2 receptors and on the dose and type of antipsychotic medication. It has been suggested that a low availability of these receptors may increase the risk for addictive behavior.


OBJECTIVE
This study aims to show that patients with relatively high occupancy of D2 receptors by antipsychotic drugs are more prone to nicotine consumption.


METHODS
Striatal D2 receptor occupancy by equivalent doses of olanzapine or risperidone was assessed with [123I]iodobenzamide single-photon emission computed tomography (SPECT) in 36 patients with schizophrenia. Smoking status at the time of SPECT imaging was assessed. The number of cigarettes used in the following three consecutive years was estimated with the Life Chart Schedule (LCS).


RESULTS
There was a positive and significant relation between D2 receptor occupancy following treatment with olanzapine (n=19) or risperidone (n=12) and the number of cigarettes smoked in three consecutive years (r=0.60, p<0.001) in patients who smoked. There was a significant difference in the percentage of D2 occupancy for smokers (mean 74.3%, SD 12.8, n=31) and nonsmokers (mean 49.8%, SD 9.1, n=5).


CONCLUSIONS
Frequency of cigarette smoking in schizophrenic patients treated with antipsychotic medication is significantly and negatively related to the availability of striatal D2 receptors.
de Haan
Lieuwe
L
Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. l.dehaan@amc.uva.nl
Booij
Jan
J
Lavalaye
Jules
J
van Amelsvoort
Therese
T
Linszen
Don
D
D000328:Adult; D014150:Antipsychotic Agents / Q000009:adverse effects* / Q000494:pharmacology / Q000627:therapeutic use; D001569:Benzodiazepines / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use; D001667:Binding, Competitive / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D000077152:Olanzapine; D017448:Receptors, Dopamine D2 / Q000187:drug effects*; D018967:Risperidone / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use; D012559:Schizophrenia / Q000150:complications* / Q000000981:diagnostic imaging / Q000188:drug therapy; D012565:Schizophrenic Psychology; D012907:Smoking / Q000378:metabolism / Q000523:psychology; D014029:Tobacco Use Disorder / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000523:psychology*; D015899:Tomography, Emission-Computed, Single-Photon
D014150:Antipsychotic Agents; D017448:Receptors, Dopamine D2; D001569:Benzodiazepines; D018967:Risperidone; D000077152:Olanzapine