Dopaminergic activity in depressed smokers: a positron emission tomography study.
Tobacco dependence is highly prevalent in depressed patients. We assessed changes in [(11)C]-raclopride binding potential (BP) using positron emission tomography (PET) before and after the oral administration of d-amphetamine in healthy controls and unmedicated patients with current depression with and without current tobacco dependence. Over a single study day 2 [(11)C]-raclopride positron emission tomography scans were taken in 38 subjects: at baseline and 2 h following oral d-amphetamine 30 mg. Twenty controls (9 smokers, 11 nonsmokers) and 18 subjects with current major depressive episode (8 smokers, 10 non-smokers). Striatal [(11)C]-raclopride binding potential was measured before and after d-amphetamine administration. Depressed smokers had a lower baseline [(11)C]-raclopride binding potential compared with both control non-smokers (P < 0.007) and depressed non-smokers (P < 0.001). There was a main effect of smoking status on amphetamine-induced change in [(11)C]-raclopride binding potential (P < 0.02), but no main effect of depression. This may be due to a floor effect because of the low BP at baseline. Depressed subjects reported significant increase of positive mood after d-amphetamine administration compared with controls (depressed smokers vs. control smokers: P < 0.05; depressed non-smokers vs. controls: P < 0.055). Tobacco dependence appears to decrease d-amphetamine-induced changes in [(11)C]-raclopride binding potential as measured by positron emission tomography. Comorbid major depression and tobacco dependence exacerbates this effect, suggesting an altered dopamine system in comorbid patients.
Busto
Usoa E
UE
Clinical Neuroscience Section, Neuroscience Research Department, Centre for Addiction and Mental Health, Toronto, Ontario, Canada. usoa_busto@camh.net
Redden
Laura
L
Mayberg
Helen
H
Kapur
Shitij
S
Houle
Sylvain
S
Zawertailo
Laurie A
LA
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000661:Amphetamine / Q000494:pharmacology; D001667:Binding, Competitive / Q000187:drug effects; D003863:Depression / Q000000981:diagnostic imaging* / Q000209:etiology*; D004298:Dopamine / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000378:metabolism; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D049268:Positron-Emission Tomography; D020891:Raclopride / Q000378:metabolism; D016037:Single-Blind Method; D013223:Statistics as Topic; D014029:Tobacco Use Disorder / Q000150:complications*; D055815:Young Adult
D018492:Dopamine Antagonists; D018765:Dopamine Uptake Inhibitors; D020891:Raclopride; D000661:Amphetamine; D004298:Dopamine