Sleep quality improves during treatment with repetitive transcranial magnetic stimulation (rTMS) in patients with cocaine use disorder: a retrospective observational study

BACKGROUND

Sleep disturbance is a prominent and common complaint in people with cocaine use disorder (CUD), either during intake or withdrawal. Repetitive transcranial magnetic stimulation (rTMS) has shown promise as a treatment for CUD. Thus, we evaluated the relationship between self-perceived sleep quality and cocaine use pattern variables in outpatients with CUD undergoing an rTMS protocol targeted at the left dorsolateral prefrontal cortex.

METHODS

This is a retrospective observational study including 87 patients diagnosed with CUD according to the DSM-5 criteria. Scores in Pittsburgh Sleep Quality Index (PSQI), Cocaine Craving Questionnaire (CCQ), Beck Depression Inventory-II (BDI-II), Self-rating Anxiety Scale (SAS), and Symptoms checklist 90-Revised (outcome used: Global Severity Index, GSI) were recorded at baseline, and after 5, 30, 60, and 90 days of rTMS treatment. Cocaine use was assessed by self-report and regular urine screens.

RESULTS

Sleep disturbances (PSQI scores > 5) were common in patients at baseline (mean ± SD; PSQI score baseline: 9.24 ± 3.89; PSQI > 5 in 88.5% of patients). PSQI scores significantly improved after rTMS treatment (PSQI score Day 90: 6.12 ± 3.32). Significant and consistent improvements were also seen in craving and in negative-affect symptoms compared to baseline. Considering the lack of a control group, in order to help the conceptualization of the outcomes, we compared the results to a wait-list group (n = 10). No significant improvements were observed in the wait-list group in any of the outcome measures.

CONCLUSIONS

The present findings support the therapeutic role of rTMS interventions for reducing cocaine use and accompanying symptoms such as sleep disturbance and negative-affect symptoms.

TRIAL REGISTRATION

ClinicalTrials.gov.NCT03733821.

Neurite orientation dispersion and density imaging in cocaine use disorder

Cocaine use disorder (CUD) is characterized by a compulsive search for cocaine. Several studies have shown that cocaine users exhibit cognitive deficits, including lack of inhibition and decision-making as well as brain volume and diffusion-based white-matter alterations in a wide variety of brain regions. However, the non-specificity of standard volumetric and diffusion-tensor methods to detect structural micropathology may lead to wrong conclusions. To better understand microstructural pathology in CUD, we analyzed 60 CUD participants (3 female) and 43 non-CUD controls (HC; 2 female) retrospectively from our cross-sectional Mexican SUD neuroimaging dataset (SUDMEX-CONN), using multi-shell diffusion-weighted imaging and the neurite orientation dispersion and density imaging (NODDI) analysis, which aims to more accurately model microstructural pathology. We used Viso values of NODDI that employ a three-compartment model in white (WM) and gray-matter (GM). These values were also correlated with clinical measures, including psychiatric severity status, impulsive behavior and pattern of cocaine and tobacco use in the CUD group. We found higher whole-brain microstructural pathology in WM and GM in CUD patients than controls. ROI analysis revealed higher Viso-NODDI values in superior longitudinal fasciculus, cingulum, hippocampus cingulum, forceps minor and Uncinate fasciculus, as well as in frontal and parieto-temporal GM structures. We also found correlations between significant ROI and impulsivity, onset age of cocaine use and weekly dosage with Viso-NODDI. However, we did not find correlations with psychopathology measures. Overall, although their clinical relevance remains questionable, microstructural pathology seems to be present in CUD both in gray and white matter.

Randomized placebo-controlled trial of galantamine in individuals with cocaine use disorder

No pharmacotherapies are approved for the treatment of cocaine use disorder (CUD). Galantamine, a cholinesterase inhibitor, has shown initial promise for cocaine use reduction in methadone-maintained individuals with CUD and cognitive improvement in abstinent individuals with past CUD. However, galantamine has not previously tested in individuals with current CUD and no comorbid opioid use disorder or methadone maintenance. The goal of this 13-week, double-blind, placebo-controlled, randomized controlled trial was to test the efficacy of galantamine (8 mg or 16 mg/day; extended release (ER)) for reducing cocaine use and improving cognitive function in individuals with cocaine use disorder (CUD). Ninety-three treatment-seeking cocaine users were randomized to placebo (n = 32), 8 mg/day galantamine (n = 31) or 16 mg/day galantamine (n = 30). The medication was well-tolerated with minimal reports of side-effects. However, there were no significant treatment group differences in cocaine use outcomes (as measured by self-report or urines). The 16 mg galantamine group had a greater improvement in working memory capacity (Backwards Digit Span), but there were no other significant treatment group differences on key cognitive outcomes. These findings did not provide support for the efficacy of galantamine as a treatment for cocaine use in this sample of individuals with CUD.

[11C]MK-6884 PET imaging reveals lower M4 muscarinic acetylcholine receptor availability following cocaine self-administration in male rats

BACKGROUND

Cocaine Use Disorder (CUD) remains a significant problem in the United States, with high rates of relapse and no present FDA-approved treatment. The acetylcholine neurotransmitter system, specifically through modulation of muscarinic acetylcholine receptor (mAChR) function, has shown promise as a therapeutic target for multiple aspects of CUD. Enhancement of the M4 mAChR subtype via positive allosteric modulation has been shown to inhibit the behavioral and neurochemical effects of cocaine across several rodent models of CUD. However, it is unclear how cocaine exposure affects M4 mAChR expression or distribution.

OBJECTIVES

To evaluate the effects of cocaine self-administration on M4 mAChR availability using [11C]MK-6884 in vivo PET imaging in rats that self-administered cocaine (cocaine SA) or sucrose pellets (control).

METHODS

Sprague-Dawley rats self-administered cocaine or sucrose pellets for 15 days under 2-h or 4-h sessions followed by PET imaging with [11C]MK-6884, a radiolabeled M4 selective positive allosteric modulator to determine the effects of cocaine on [11C]MK-6884 standard uptake values with cerebellum as reference (SUVr).

RESULTS

Cumulative cocaine intake ranged between 324 and 776 mg/kg. Cocaine self-administration was associated with significantly lower [11C]MK-6884 SUVrs in the cortex, hippocampus, and striatum compared to cocaine-naive rats, with a negative correlation between radiotracer SUVrs and cocaine intake in the hippocampus.

CONCLUSIONS

These results suggest that cocaine self-administration decreases M4 mAChR availability, providing further support for pursuing activation/enhancement of M4 mAChR function as a viable pharmacotherapeutic approach for CUD.