Effect of a history of major depressive disorder on smoking-induced dopamine release.
BACKGROUND
Dopamine (DA) system dysfunction is implicated in the pathophysiology of major depressive disorder (MDD). We sought to determine if cigarette smokers with a history of MDD and current mild depressive symptoms have abnormal smoking-induced DA release (measured indirectly as change in (11)C-raclopride binding potential [BP(ND)]).


METHODS
Fifty-six cigarette smokers either with (n = 10) or without (n = 46) a history of MDD (MDD+ and MDD-, respectively) underwent bolus-plus-continuous-infusion (11)C-raclopride positron emission tomography, during which they smoked a regular cigarette. Presmoking to postsmoking changes in (11)C-raclopride BP(ND) were compared between groups. Also, correlations were determined between change in BP(ND) and depression, anxiety, and withdrawal rating scale scores for the MDD+ group.


RESULTS
The MDD+ group had a significantly greater reduction in (11)C-raclopride BP(ND) (-16.3%) than the MDD- group (-8.4%) (analysis of covariance [ANCOVA], p = .03). Significant negative correlations were found between depression/anxiety and change in (11)C-raclopride BP(ND) (r = -.77, p < .01 and r = -.74, p = .01, respectively).


CONCLUSIONS
MDD+ smokers have greater smoking-induced DA release than MDD- smokers, and higher depression/anxiety levels are associated with greater smoking-induced DA release. These findings support the theory that MDD+ smokers have DA system dysfunction, including heightened smoking-induced DA release.
Brody
Arthur L
AL
Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, California 90095, USA. abrody@ucla.edu
Olmstead
Richard E
RE
Abrams
Anna L
AL
Costello
Matthew R
MR
Khan
Aliyah
A
Kozman
Daniel
D
Saxena
Sanjaya
S
Farahi
Judah
J
London
Edythe D
ED
Mandelkern
Mark A
MA
D000328:Adult; D000368:Aged; D001007:Anxiety / Q000378:metabolism; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism; D003865:Major Depressive Disorder / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D020891:Raclopride / Q000378:metabolism; D011869:Radioligand Assay; D012907:Smoking / Q000378:metabolism*; D013375:Substance Withdrawal Syndrome / Q000378:metabolism; D014029:Tobacco Use Disorder / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism
D020891:Raclopride; D004298:Dopamine