Repetitive transcranial magnetic stimulation (rTMS) can improve cognitive function and reduce cravings in people addicted to methamphetamine, according to a study recently published in Drug and Alcohol Dependence.
Methamphetamine is a strong stimulant of the central nervous system that is used as a recreational drug all over the world. Part of the reason why people become addicted to substances like methamphetamine is because of cravings. Cravings occur when the user’s body begins to expect the drug and if the drug is given it will eliminate the associated unpleasant withdrawal symptoms.
Methamphetamine craving occurs through a number of brain networks including the prefrontal cortex (PFC). Abnormal PFC functioning produces impulsive behaviour, obsessive-compulsive symptoms and attention deficits. These factors are thought to contribute to the loss of control that leads to drug addiction. In fact, methamphetamine addicts have been shown to have deficits in a specific area of the PFC known as the dorsolateral prefrontal cortex (DLPFC), which is involved in reward and decision-making.
Methamphetamine abuse is a big problem for public health services and currently there is no treatment for methamphetamine addiction. Previous research has revealed that repetitive transcranial magnetic stimulation (rTMS) over the DLPFC reduces cravings in substance abusers of cocaine, heroin and alcohol. But this research had not been carried out on methamphetamine users. In an attempt to find a treatment for methamphetamine addiction a team of scientists from Shanghai Jiao Tong University, China tested high frequency rTMS on a group of methamphetamine users. Fifteen participants received 5 sessions of rTMS treatment and the other 15 received 5 fake sessions.
The results showed that high frequency rTMS of the DLPFC reduced cravings in methamphetamine addicts without any adverse side effects. rTMS additionally improved the learning, memory and social cognition of methamphetamine addicts. This is a finding that has been replicated in studies using healthy volunteers and patients with schizophrenia, although the underlying mechanism is not yet clear. Furthermore, in this study the oldest participants with the lowest level of education responded the best to rTMS treatment. Although this is a finding that has not frequently been reported in previous studies.
Overall, this study demonstrates that high frequency rTMS over the DLPFC could potentially be used as a craving-reducing treatment for methamphetamine addicts, whilst also enhancing their PFC performance.