Use of experimental medicine approaches for the development of novel psychiatric treatments based on orexin receptor modulation

Pharmacological management of gambling disorder: an update of the literature

INTRODUCTION

Gambling disorder (GD) is a mental health condition characterized by persistent and problematic betting behavior. GD generates distress and impairment, and treatment options include psychological and pharmacological interventions.

AREAS COVERED

This narrative review explores existing pharmacological treatments for GD. The following classes of medications were considered: opioid-receptor antagonists (e.g. naltrexone and nalmefene), serotonin reuptake inhibitors (e.g. fluvoxamine, paroxetine, sertraline, escitalopram, and citalopram), glutamatergic agents (e.g. N-acetylcysteine (NAC), acamprosate, and memantine), mood stabilizers (e.g. topiramate, carbamazepine, lithium), and other medications (e.g. modafinil, nefazodone, olanzapine, haloperidol, tolcapone, and bupropion).

EXPERT OPINION

Due to the limitations of the studies reviewed, solid conclusions regarding the optimal choice of pharmacotherapy for individuals with GD are challenging to draw at this time. Despite some medications, such as naltrexone and nalmefene, showing promising results, efficacy has varied across studies. The review highlights current gaps/limitations, including small sample sizes, limited diversity in participant demographics, the need for exploring different gambling subtypes and treatment responses, high placebo response rates, lack of longer-term longitudinal information, limited investigation of neurobiological correlates and co-occurring disorders, and the importance of implementation research. Further research is needed to address these gaps and explore additional medications, as well as interventions like neuromodulation.

Neurobiology of Stress-Induced Nicotine Relapse

Tobacco smoking is the leading cause of preventable death and disease. Although there are some FAD-approved medicines for controlling smoking, the relapse rate remains very high. Among the factors that could induce nicotine relapse, stress might be the most important one. In the last decades, preclinical studies have generated many new findings that lead to a better understanding of stress-induced relapse of nicotine-seeking. Several molecules such as α3β4 nicotinic acetylcholine receptor, α2-adrenergic receptors, cannabinoid receptor 1, trace amine-associated receptor 1, and neuropeptide systems (corticotropin-releasing factor and its receptors, dynorphine and kappa opioid receptor) have been linked to stress-induced nicotine relapse. In this review, we discuss recent advances in the neurobiology, treatment targets, and potential therapeutics of stress-induced nicotine relapse. We also discuss some factors that may influence stress-induced nicotine relapse and that should be considered in future studies. In the final section, a perspective on some research directions is provided. Further investigation on the neurobiology of stress-induced nicotine relapse will shed light on the development of new medicines for controlling smoking and will help us understand the interactions between the stress and reward systems in the brain.

Efficacy, safety, and tolerability of nivasorexant in adults with binge-eating disorder: A randomized, Phase II proof of concept trial

OBJECTIVE

This Phase II, placebo-controlled, double-blind study investigated the efficacy, safety, and tolerability of nivasorexant in the treatment of adults with moderate to severe binge-eating disorder (BED).

METHODS

Adults meeting the DSM-5 BED criteria were randomized 1:1 to placebo or nivasorexant (100 mg b.i.d.). The primary endpoint was the change from baseline to Week 12 in the number of binge eating (BE) days per week. Exploratory efficacy endpoints included cessation of BE in the last 4 weeks of treatment; and change from baseline to Week 12 in the number of BE episodes/week, the clinician global impression (CGI) of change, the Yale-Brown Obsessive-Compulsive Scale modified for BE, and the Hamilton rating scale for depression (HAMD-17). Key safety outcomes included treatment-emergent adverse events (TEAEs) and adverse events of special interest (i.e., somnolence and fatigue).

RESULTS

Sixty-eight participants were randomized to each treatment arm. The change from baseline to Week 12 in the number of BE days/week was the same for placebo (least squares mean [LSM]: -2.93) and nivasorexant (LSM: -2.93), with no difference between the treatment groups (LSM difference = .000 [95% confidence interval (CI): -.69, .69], p = .9992). Furthermore, no differences between treatment groups were observed in the exploratory efficacy endpoints. Nivasorexant was well tolerated; the overall incidence of TEAEs was balanced between treatment groups, and the frequency of somnolence and fatigue in the nivasorexant group were similar to placebo.

DISCUSSION

In this proof-of-concept study, 100 mg b.i.d. nivasorexant did not improve BE in adults with moderate to severe BED.

PUBLIC SIGNIFICANCE

The results of this Phase II study indicate that nivasorexant was well tolerated in adults with BED, but did not improve binge eating behavior over placebo. Further research is needed to improve our understanding of the role of the orexin-1 receptor in BED.