Low-intensity focused ultrasound targeting the nucleus accumbens as a potential treatment for substance use disorder: safety and feasibility clinical trial

Introduction

While current treatments for substance use disorder (SUD) are beneficial, success rates remain low and treatment outcomes are complicated by co-occurring SUDs, many of which are without available medication treatments. Research involving neuromodulation for SUD has recently gained momentum. This study evaluated two doses (60 and 90 W) of Low Intensity Focused Ultrasound (LIFU), targeting the bilateral nucleus accumbens (NAc), in individuals with SUD.

Methods

Four participants (three male), who were receiving comprehensive outpatient treatment for opioid use disorder at the time of enrollment and who also had a history of excessive non-opioid substance use, completed this pilot study. After confirming eligibility, these participants received 10 min sham LIFU followed by 20 min active LIFU (10 min to left then right NAc). Outcomes were the safety, tolerability, and feasibility during the LIFU procedure and throughout the 90-day follow-up. Outcomes also included the impact of LIFU on cue-induced substance craving, assessed via Visual Analog Scale (VAS), both acutely (pre-, during and post-procedure) and during the 90-day follow-up. Daily craving ratings (without cues) were also obtained for one-week prior to and one-week following LIFU.

Results

Both LIFU doses were safe and well-tolerated based on reported adverse events and MRI scans revealed no structural changes (0 min, 24 h, and 1-week post-procedure). For the two participants receiving "enhanced" (90 W) LIFU, VAS craving ratings revealed active LIFU attenuated craving for participants' primary substances of choice relative to sham sonication. For these participants, reductions were also noted in daily VAS craving ratings (0 = no craving; 10 = most craving ever) across the week following LIFU relative to pre-LIFU; Participant #3 pre- vs. post-LIFU: opioids (3.6 ± 0.6 vs. 1.9 ± 0.4), heroin (4.2 ± 0.8 vs. 1.9 ± 0.4), methamphetamine (3.2 ± 0.4 vs. 0.0 ± 0.0), cocaine (2.4 ± 0.6 vs. 0.0 ± 0.0), benzodiazepines (2.8 ± 0.5 vs. 0.0 ± 0.0), alcohol (6.0 ± 0.7 vs. 2.7 ± 0.8), and nicotine (5.6 ± 1.5 vs. 3.1 ± 0.7); Participant #4: alcohol (3.5 ± 1.3 vs. 0.0 ± 0.0) and nicotine (5.0 ± 1.8 vs. 1.2 ± 0.8) (all p's < 0.05). Furthermore, relative to screening, longitudinal reductions in cue-induced craving for several substances persisted during the 90-day post-LIFU follow-up evaluation for all participants.

Discussion

In conclusion, LIFU targeting the NAc was safe and acutely reduced substance craving during the LIFU procedure, and potentially had longer-term impact on craving reductions. While early observations are promising, NAc LIFU requires further investigation in a controlled trial to assess the impact on substance craving and ultimately substance use and relapse.

Focused Ultrasound Neuromodulation: Exploring a Novel Treatment for Severe Opioid Use Disorder

BACKGROUND

Opioid use disorder remains a critical health care challenge because current therapeutic strategies have limitations that result in high recurrence and deaths. We evaluated the safety and feasibility of focused ultrasound (FUS) neuromodulation to reduce substance cravings and use in severe opioid and co-occurring substance use disorders.

METHODS

This prospective, open-label, single-arm study enrolled 8 participants with severe, primary opioid use disorder with co-occurring substance use. Participants received a 20-minute session of low-intensity FUS (220 kHz) neuromodulation targeting the bilateral nucleus accumbens (NAc) with follow-up for 90 days. Outcome measures included safety, tolerability, feasibility, and effects of FUS neuromodulation by assessment of adverse events, substance craving, substance use (self-report, urine toxicology), mood, neurological examinations, and anatomical and functional magnetic resonance imaging (fMRI) at 1, 7, 30, 60, and 90 days post-FUS.

RESULTS

No serious device-related adverse events or imaging abnormalities were observed. Following FUS, participants demonstrated immediate (p < .002) and sustained (p < .0001; mean 91%) reductions in cue-induced opioid craving, with median ratings on a scale from 0 to 10 as follows: 6.9 (pre-FUS) versus 0.6 (90-day post-FUS). Craving reductions were similar for other illicit substances (e.g., methamphetamine [p < .002], cocaine [p < .02]). Decreases in opioid and co-occurring substance use were confirmed by urine toxicology. Seven participants remained abstinent at 30 days; 5 participants remained abstinent throughout 90 days post-FUS. Resting-state fMRI demonstrated decreased connectivity from the NAc to reward and cognitive regions post-FUS.

CONCLUSIONS

NAc FUS neuromodulation is safe and a potential adjunctive treatment for reducing drug cravings and use in individuals with severe opioid and co-occurring substance use disorders. Larger, sham-controlled, randomized studies are warranted.

Safety and feasibility clinical trial of nucleus accumbens deep brain stimulation for treatment-refractory opioid use disorder

OBJECTIVE

There were more than 107,000 drug overdose deaths in the US in 2021, the most ever recorded. Despite advances in behavioral and pharmacological treatments, over 50% of those receiving treatment for opioid use disorder (OUD) experience drug use recurrence (relapse). Given the prevalence of OUD and other substance use disorders (SUDs), the high rate of drug use recurrence, and the number of drug overdose deaths, novel treatment strategies are desperately needed. The objective of this study was to evaluate the safety and feasibility of deep brain stimulation (DBS) targeting the nucleus accumbens (NAc)/ventral capsule (VC) and potential impact on outcomes in individuals with treatment-refractory OUD.

METHODS

A prospective, open-label, single-arm study was conducted among participants with longstanding treatment-refractory OUD (along with other co-occurring SUDs) who underwent DBS in the NAc/VC. The primary study endpoint was safety; secondary/exploratory outcomes included opioid and other substance use, substance craving, and emotional symptoms throughout follow-up and 18FDG-PET neuroimaging.

RESULTS

Four male participants were enrolled and all tolerated DBS surgery well with no serious adverse events (AEs) and no device- or stimulation-related AEs. Two participants sustained complete substance abstinence for > 1150 and > 520 days, respectively, with significant post-DBS reductions in substance craving, anxiety, and depression. One participant experienced post-DBS drug use recurrences with reduced frequency and severity. The DBS system was explanted in one participant due to noncompliance with treatment requirements and the study protocol. 18FDG-PET neuroimaging revealed increased glucose metabolism in the frontal regions for the participants with sustained abstinence only.

CONCLUSIONS

DBS of the NAc/VC was safe, feasible, and can potentially reduce substance use, craving, and emotional symptoms in those with treatment-refractory OUD. A randomized, sham-controlled trial in a larger cohort of patients is being initiated.