Phenomenology and neurobiology of cocaine withdrawal: are they related?

1. The presence of mood disturbances and platelet 3H-imipramine binding, a putative peripheral serotonergic marker, were evaluated in a group of 27 cocaine users three days after drug withdrawal. 2. Parameters of cocaine use and the linkage between cocaine withdrawal and "post-cocaine depression" were also investigated. In a subgroup of 10 patients, both psychopathological and biological measurements were repeated after 5 or 6 weeks. 3. Interpretation of the data by Pearson's analysis showed a statistically significant and positive correlation between Hamilton Rating Scale for Depression (HAM-D) scores and period of use. A trend towards a negative correlation, which however did not reach the statistical significance, was found between 3H-Imipramine binding and period of cocaine use, number of days of abstinence and HAM-D scores 4. When compared with normal volunteers at baseline, patients had significantly lower Bmax and Kd values which returned towards normal values after 5 or 6 weeks of cocaine withdrawal. 5. These results indicate the presence of a decreased platelet imipramine binding during cocaine withdrawal which may be due to the effect of the drug or alternatively, a result of concomitant depression which may be primary or secondary in origin. The decreased imipramine binding is a reversible phenomenon, since it increases with the time, in parallel with the improvement of depressive symptoms.