In a retrospective observational study, participants receiving 20-30 rTMS sessions delivered over a course of 4-6 weeks showed significant reductions in both craving and depression symptom scores.
In addition, the researchers found that the number of rTMS sessions significantly predicted the number of days of drug abstinence, even after controlling for confounders.
“For each additional TMS session, there was an additional 10 days of abstinence in the community,” principal investigator Wael Foad, MD, medical director, Erada Center for Treatment and Rehabilitation, Dubai, United Arab Emirates, told this news organization.
However, Dr. Foad noted that he would need to construct a randomized controlled trial to further explore that “interesting” finding.
The results were published in the Annals of Clinical Psychiatry.
Inpatient program
The researchers retrospectively analyzed medical records of men admitted to the inpatient unit at the Erada Center between June 2019 and September 2020. The vast majority were native to the UAE.
The inpatient program focuses on treating patients with SUDs and is the only dedicated addiction rehabilitation service in Dubai, the investigators noted.
They analyzed outcomes for 55 men with mild to moderate MDD who received rTMS as standard treatment.
Participants were excluded from the data analysis if they had another comorbid diagnosis from the DSM-5 other than SUD or MDD. They were also excluded if they used an illicit substance 2 weeks before the study or used certain medications, including antipsychotics, benzodiazepines, or mood stabilizers.
When patients first arrived on the unit, they were detoxed for a period of time before they began receiving rTMS sessions.
The 55 men received 20-30 high-frequency rTMS sessions over the course of 4-6 weeks in the area of the dorsolateral prefrontal cortex. Each session consisted of 3,000 pulses delivered over a period of 37.5 minutes. Severity of depression was measured with the Clinical Global Impression–Severity Scale (CGI-S), which uses a 7-point Likert scale.
In addition, participants’ scores were tracked on the Brief Substance Craving Scale (BSCS), a self-report scale that measures craving for primary and secondary substances of abuse over a 24-hr period.
Of all participants, 47% said opiates and 35% said methamphetamine were their primary substances of abuse.
Significant improvement
Results showed a statistically significant improvement (P < .05) between baseline and post-rTMS treatment scores in severity of depression and drug craving, as measured by the BSCS and the CGI-S.
The researchers noted that eight participants dropped out of the study after their first rTMS session for various reasons.
Dr. Foad explained that investigators contracted with study participants to receive 20 rTMS sessions; if the sessions were not fully completed during the inpatient stay, the rTMS sessions were continued on an outpatient basis. A study clinician closely monitored patients until they finished their sessions.
For each additional rTMS session the patients completed beyond 20 sessions, there was an associated excess of 10 more days of abstinence from the primary drug in the community.
The investigators speculated that rTMS may reduce drug craving by increasing dopaminergic binding in the striatum, or by releasing dopamine in the caudate nucleus.
Study limitations cited include the lack of a control group and the fact that the study sample was limited to male inpatients, which limits generalizability of the findings to other populations.