TMS AND SUBSTANCE USE DISORDER

Substance abuse is clearly a major cause for concern, affecting millions of Americans, often with considerable impact to people's lives, livelihoods, and families.  Addiction is characterized by cravings, withdrawal, and tolerance.  Often people with substance abuse make multiple attempts to quit, and unfortunately not infrequently, these attempts fail.  As time goes on, the addiction typically takes a larger and larger toll on the person's life.  It can affect their health, their relationships, career, finances and even result in legal problems.  The effect on those who love them can also be quite devastating.

With the increase over the last several years in opioid abuse, we are seeing not only more addiction, but more deaths.  The influx of high potency synthetic opioids such as fentanyl has resulted in a fivefold increase in opioid related deaths since 2010, although there is some indication that this may be leveling off.  But leveling off at 111,000 deaths a year is nothing to be complacent about.  The problem is that fentanyl is so potent that even a small mistake in making the batch of drugs can result in a much higher dose than the user thinks they are taking.  Plus, Fentanyl is now being added to all kinds of other drugs such as MDMA (Molly, ecstasy), cocaine, other opioids, etc.  People who have no tolerance to opioids because they are not habitual users, take these other drugs, perhaps even recreationally, and wind-up overdosing and dying.

So, the stakes could not be higher.  The TMS community is wondering if TMS could be useful for substance use disorders.  On paper it would make sense.  The most common targets for TMS, the dorsolateral prefrontal cortex and the dorsomedial prefrontal cortex are part of the brain network involved in emotional regulation and self-control.  These would seem to be relevant to substance use, and in fact the dorsolateral prefrontal cortex has been demonstrated to be involved in cravings, inhibitory control and perhaps relapse.

Thus far, there have only been a few well-done studies, however, employing TMS to treat substance abuse.  Unfortunately, even the good studies have been inconsistent regarding the protocols that they have used, and some appear to involve protocols that are inadequate compared to the protocols that we are using now for depression for instance.  Consequently, the results so far have been variable with both positive and negative findings.  In one small pilot study from 2018, for example, Martinez et. al. delivered 3 weeks of TMS to cocaine users (current depression protocols are for 6 weeks), and demonstrated decreased self-administration compared with the placebo group.

Also consider that "substance abuse" is not a monolithic entity.  It is quite possible that TMS may be helpful for several substances, but not others.  Looking at cigarette smoking cessation, for example, there is much more solid evidence for the benefits of TMS, and the FDA has even cleared the use of TMS for smoking cessation.  This will be the subject of a subsequent article. Right now, there is not enough evidence to support using TMS for substance abuse, but there are hopeful hints, and it is an area of active, ongoing research.  The need is great, current treatments are often inadequate, and lives are at stake.

REFERENCES:

Effect of High-Frequency Transcranial Magnetic Stimulation on Craving in Substance Use Disorder: A Meta-Analysis. Rituparna Maiti, M.D., Biswa Ranjan Mishra, M.D., Debasish Hota, D.M. Published Online:6 Oct 2016https://doi.org/10.1176/appi.neuropsych.16040065

Non-Invasive Brain Stimulation in Substance Use Disorders: Implications for Dissemination to Clinical Settings Elena R. Stein,a Benjamin C. Gibson,a Victoria R. Votaw,a Adam D. Wilson,a Vincent P. Clark,a and Katie WitkiewitzaCurr Opin Psychol. 2019 Dec; 30: 6–10. Published online 2018 Dec 19. doi: 10.1016/j.copsyc.2018.12.009

Transcranial magnetic stimulation of medial prefrontal and cingulate cortices reduces cocaine self-administration: A pilot study. Martinez D, Urban N, Grassetti A, Chang D, Hu MC, Zangen A, Levin FR, Foltin R, Nunes E V: Front Psychiatry 2018, 9:10–15