D-TMS IN COCAINE ADDICTION: preliminary findings

Abstract

Cocaine-related disorders are currently among the most devastating mental disease as they leads to profound disturbances in an individual’s behaviour resulting in tremendous economic, social, and moral costs. Imaging studies in human have shown a reduction of dopamine (DA) receptors accompanied by a lesser release of endogenous DA in the ventral striatum (AVT) of cocaine subjects thereby resulting in a ‘dopamine-impoverished’ brain[1-2]. This perturbations lead to neuroadpatations in several other circuits which are related to motivation, inhibitory control, and memory which finally determ compulsive-impulsive self drug administration[3]. The lasting reduction in physiological activity of the DA system leads to the idea that an increment on its activity, to restore pre-drug levels, may yield significant clinical improvements[2]. There is a substantial need for therapeutic tools in addictive states and TMS appears to be a promising ‘non-pharmacologic’ candidate, since it can modulate the DA system and the function of related areas[4]. It has been just reported[5] that rTMS over the left dorso-lateral prefrontal cortices (DLPfcx) temporarily reduces the craving for cocaine in cocaine addicts but there are no studies which have investigated the TMS effects in the cocaine intake. Considering that we applied bilateral deep-rTMS to the DLPfcx of cocaine abusers, in order (1) to evaluate the short/long term therapeutic effects of TMS in cocaine intake trough hair analysis during the time line (T0,T1,T2,T3.. ), (2) to identify optimal parameters of stimulation (1HZ/10HZ), (3) to highlight possible correlation between cocaine intake and clinical parameters. 20 cocaine abusers have been recruited selected on the DSM-IV criteria and randomly assigned to real rTMS group (100% of motor threshold, 10 HZ/1 HZ, 5 second per train, 20 trains, 15 seconds of inter-stimulus) or to sham stimulation one. In order to investigate the effect of TMS on cocaine dependence we assessed the cocaine intake trough hair analysis before (T0) and after treatment (T1) and every 3 months for the follow-up data. The interim analysis shows that all subjects have reduced the intake of cocaine regardless of the frequency (10 Hz or sham condition) of the stimulation protocol applied. Six months after the treatment (T2) all treated subjects show a reduction in cocaine intake with no distinction among groups (real vs sham). 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. We hypothesize an initial placebo/sham effect which disappears over time in the sham patients group. More cases are needed in 1 hz and sham condition to balance the groups. 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. References 1 Volkow et al., 2010 Bioessays 32(9):748-755 2 Diana, 2011 Front Psychi 2:64 3 Volkow et al., 2004 Neurophar 47:3-13 4 Feil et al., 2010 Neurosci&Biobe 35:248-275 5 Politi et al., 2008 Am J on Add, Vol.17(4): 345-346