TRANSCRANICAL MAGNETIC STIMULATION IN COCAINE ADDICTION:PRELIMINARY FINDINGS

Abstract

Drug addiction is a brain disease which leads to profound disturbances in an individual’s behaviour. In spite of the progress made in the understanding of the neurobiological mechanisms underlying addiction, expectations from a therapeutic point of view have not been satisfying. Given the modest efficacy of therapeutic tools available, Transcranial Magnetic Stimulation (TMS) seems to be a promising “non-pharmacologic” aid in various neuropathologies including addiction which is characterized by a decrease of dopaminergic activity (DA). Thus, ‘restoring’ pre-pathology DA activity may yield clinical benefits in addicts. In particular, it has been reported that TMS reduces the craving for cocaine in cocaine addicts. Thus, the main aims of the present project is to apply bilateral dTMS to the Dorso-Lateral Pre-frontal Cortices of cocaine abusers in order to deepen understanding the neural correlates of addiction; to identify optimal parameters of stimulation; and, above all, to evaluate short/long term therapeutic effects of dTMS. Wee applied dTMS in nineteen cocaine abusers (average age: 34,57; F: 2; M: 17) selected on DSM IV criteria and randomly assigned to real/sham stimulation protocols. Fourteen of them are currently included in the study while four abandoned due to personal problems (4 drop-out) and one has been excluded because he did not satisfy inclusion criteria. We assessed the intake of cocaine through self-reports and hair analysis at different times pre- (T0) and post-treatment (T1 T2 T3..). We considered the psycho-social impact of Addiction behaviour by assessing the anxiety (STAY-1; STAY-2 ) and the several dimension of hostility (BDHI ) before and after stimulation (T0, T1,T2,T3.. ). The interim analysis shows that all subjects have reduced intake of cocaine regardless of the frequency (1 Hz n. = 6 or 10 Hz n. = 8) of the stimulation protocol applied (sham condition was administered in six subjects). Six months after treatment (T3) all subjects show a reduction in cocaine intake with no distinction among groups (real vs sham nor 10 vs 1 Hz). More cases are needed in 1 Hz and sham conditions to “balance” the groups. The follow-up data, however, shows a strong persistence of the effect in the real group, and decidedly weaker maintenance in sham group. An analogues trend has been observed also in psychological dimensions. We hypothesize an initial placebo/sham effect which disappears over time in the sham patients group. Nevertheless these preliminary data encourage further investigation to evaluate the potential effects of dTMS in the treatment of cocaine abusers and in the prevention of relapses.