Dopamine transporter levels in cocaine dependent subjects.

Cocaine use is a significant problem in the US and it is well established that cocaine binds to the dopamine transporter (DAT) in the brain. This study was designed to determine if the DAT levels measured by 99mTc TRODAT SPECT (single photon emission computed tomography) brain scans are altered in cocaine dependent subjects and to explore clinical correlates of such alterations. SPECT brain scans were acquired on 21 cocaine dependent subjects and 21 healthy matched controls. There were significantly higher DAT levels in cocaine dependent subjects compared to controls for the anterior putamen (p=0.003; Cohen's d effect size=0.98), posterior putamen (p<0.001; effect size=1.32), and caudate (p=0.003; effect size=0.97). DAT levels in these regions were 10%, 17%, and 8% higher in the cocaine dependent subjects compared to controls. DAT levels were unrelated to craving, severity of cocaine use, or duration of cocaine use, but DAT levels in the caudate and anterior putamen were significantly (p<0.05) negatively correlated with days since last use of cocaine.