Relationship between Platelet Serotonin Uptake Sites and Measures of Impulsivity, Aggression, and Craving among African-American Cocaine Abusers

Abstract

We investigated whether platelet-tritiated paroxetine binding, a measure of serotonin uptake sites, and behavioral measures of impulsivity, aggression, and craving differed between cocaine-dependent subjects and controls and whether paroxetine binding was related to these behavioral measures. One hundred and five African-American cocaine-dependent outpatients and 44 African-American controls were studied. Tritiated paroxetine binding sites on platelets were assayed, and standardized assessments of impulsivity, aggression, and craving were performed. The Bmax values of paroxetine binding were significantly reduced among cocaine patients compared to controls. Cocaine patients showed significantly higher scores on certain measures of sensation seeking, impulsivity, and aggression as compared to controls. Furthermore, paroxetine binding showed a significant negative correlation with most measures of sensation seeking, impulsivity, and aggression--though not craving--among cocaine patients. Our findings indicate that densities of serotonin uptake sites may be reduced among cocaine abusers and related to impulsive-aggressive behavioral dimensions.

Use of stimulants to treat cocaine and methamphetamine abuse

“…Platelet paroxetine binding, a measure of serotonin function, was found to be lower in cocaine users than in controls, and the level of paroxetine binding inversely correlated with measures of impulsivity and aggression [ 15 ]. This study is consistent with the well-documented association between lower serotonin function and impulsivity [ 16 ].…”

Relationship of disinhibition and aggression to blunted prolactin response to meta-chlorophenylpiperazine in cocaine-dependent patients

“…Cocaine abusers consistently score higher on measures of disinhibition and report greater irritability compared to controls (Moeller et al 1994). We have previously shown that alterations in platelet 5-HT transporters, a peripheral measure of 5-HT function, were related to disinhibition and aggression in cocaine abusers (Patkar et al 2003). Therefore, measures of disinhibition and aggression appear to be appropriate clinical measures to subgroup cocaine abusers.…”

Differences in platelet serotonin transporter sites between African-American tobacco smokers and non-smokers

“…Indirect evidence implicating the 5HTT in nicotine dependence comes from studies of substance abusing individuals. Changes in platelet tritiated imipramine or paroxetine binding have been reported in alcoholics (Patkar et al 1995), heroin abusers (Macedo et al 1995), and cocaine abusers (Patkar et al 2003). Furthermore, in addition to nicotine, other constituents of tobacco smoke may also be associated with altered serotonergic function.…”

“…Based on preclinical data, we postulated that platelet 5HTT, a peripheral measure of serotonin activity, would differ between smokers and non-smokers and that severity of nicotine dependence would be related to alterations in 5HTT levels. Since behavioral measures of impulsivity and aggression may be related to platelet 5HTT levels (Coccaro et al 1996;Patkar et al 2003), we also assessed these measures in our sample. We selected a peripheral measure of serotonin activity, since there are methodological difficulties in studying central serotonin function in humans.…”