The hypodopaminergic state ten years after: transcranial magnetic stimulation as a tool to test the dopamine hypothesis of drug addiction.

An altered dopamine transmission has been described for different types of addiction for a long time. Preclinical and clinical evidence support the hypodopaminergic hypothesis and underpin the need to increase dopamine transmission to obtain therapeutic benefit. Repetitive transcranial magnetic stimulation (rTMS) of prefrontal cortex shows efficacy in treating some forms of addiction. Recent imaging studies confirmed that the therapeutic effect of rTMS is correlated with an enhancement of dopamine transmission. Novel targets for rTMS are under evaluation to increase its effectiveness in treating addiction, and research is ongoing to find the optimal protocol to boost dopaminergic transmission in the addicted brain. TMS can thus be considered a useful tool to test the dopamine hypothesis of drug addiction and instrumental in the search for addiction therapeutics.