Co-use of smoked/vaped tobacco and cannabis is increasing with expanding legalization, yet controlled clinical studies examining mechanisms underlying co-use remain limited. This study evaluated whether acute smoked cannabis influences subsequent use ("chasing") of combustible cigarettes and e-cigarettes among people who use cannabis, cigarettes, and e-cigarettes. Twenty adults who used...
Ketamine is increasingly used in community clinics as a long-term treatment for different psychiatric and pain conditions, including substance use disorders. Data are lacking, however, regarding the potential influence of ketamine on other substance use. In this secondary analysis, we aimed to explore the relationship between medical ketamine and other substance use among real-world patients by...
Major depressive disorder is a multifactorial disorder that originates from a complex web of variables and overlaps with similar disorders (e.g., depression and anxiety). As such, animal models should account for the considerable symptom overlap between psychiatric disorders. We sought to extend the findings of behavioral assays that encompass both anxiety and stress/depression components. To...
Highly potent cannabis concentrates are widely available and associated with affective disturbance and cannabis use disorder. Little is known about the effects of concentrated Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) and their relationship to long-term affect. We explored how baseline affective symptoms (anxiety and depression) relate to acute (i.e., immediate or short-term)...
The use of psychedelics for various purposes was common in different civilizations throughout human history and has been explored scientifically for more than a century. Although the applications of psychedelics show promise in the treatment of various psychiatric and neurological indications, as well as in facilitation of well-being and personal growth, several psychedelic-related risks and...
Treatment-resistant depression (TRD) is a major public health problem worldwide. There are currently five strategies for its treatment: optimization, change, combination, augmentation, and somatic therapies. However, many of these therapies are not fully effective, are not accessible, or have a significant number of side effects. Esketamine nasal spray has recently been approved, in combination...
This study was designed to explore the clinical belief that "set and setting" play an important role in favorable responses to psychedelic agents such as ketamine (KET). In fact, there is evidence in animals that the antidepressant effect of this drug may involve drug-environment interactions in which a context paired with its effects acquires the ability to influence behavior. Therefore, it...
Cannabis has been widely used medically and recreationally for centuries. With a renewed interest in the therapeutic use of cannabinoids, which are active components of Cannabis sativa, it has become important to understand the cannabinoids' neurobiological mechanisms related to both therapeutic and harmful effects. This review summarizes the effects of two major cannabinoids,...
Prior research suggests brief mindfulness (breath counting) interventions may be effective at attenuating stress-induced alcohol-related cravings. However, it remains unclear whether this reduction in craving is due to increased state mindfulness or mere distraction. To test this, the present study examined whether brief breath counting would attenuate a stress-induced increase in the relative...
Similarities between meditative and psychedelic states have long been recognized. Recently, parallels in the psychological mechanisms mediating the beneficial effects of mindfulness and psychedelic treatments-as well as their potential therapeutic complementarity-have been noted. However, empirical research in this area remains limited. Here, we explore the naturalistic use of meditation...
The use of both prescription and illicit drugs creates the potential for drug interactions as a function of both pharmacokinetic and pharmacodynamic processes. One such interaction is that of fluoxetine and methylenedioxymethamphetamine (MDMA) in which fluoxetine attenuates the positive-like effects of MDMA. The present work extends the analysis of their interaction by examining the impact of...
Hallucinogen persisting perception disorder (HPPD) is characterized by visual disturbances that resemble psychedelic intoxication and linger after use has ceased. The most common substances precipitating HPPD, lysergic acid diethylamide (LSD) and psilocybin, are posited to do so via damage to serotonergic neurons involved in vision. Mr. N is a 37-year-old with a history of alcohol, cannabis,...
The interest in psychedelic substances as potential treatments for psychiatric disorders is increasing. The β-carboline harmine, an Ayahuasca component, presents hallucinogenic and antidepressant effects. Although Ayuahuasca-and consequently harmine-is usually consumed in rituals, the role of social contexts in the behavioral effects of harmine has not been investigated yet. In this sense,...
Emerging evidence from randomized, double-blind, placebo-controlled clinical trials suggests psychedelic compounds such as 3,4-methylenedioxymethamphetamine (MDMA), psilocybin, and lysergic acid diethylamide (LSD), when administered as an adjunct to psychotherapy, that is, psychedelic-assisted psychotherapy (PAP), may be beneficial for treating substance use disorders, posttraumatic stress...
Despite research advances, it remains unclear if long-term, regular cannabis use harms cognition once intoxication has passed. Our meta-analysis aimed to investigate the association between cognitive functioning and long-term (mean ≥2 years), regular (mean ≥4 days/week), recreational cannabis use in adults during abstinence (mean ≥12 hr). We searched PubMed, PsycINFO, CINAHL, Scopus, and...
The prototype 5-HT2A receptor agonist hallucinogens LSD, mescaline, and psilocybin are classified as Schedule 1 drugs of abuse by the U.S. Drug Enforcement Administration. Accumulating clinical evidence has also suggested that acute or repeated "microdosing" with these drugs may have utility for treatment of some mental health disorders, including drug abuse and depression. The goal of the...
Cannabis can induce transient psychotic and anxiety symptoms and long-lasting disorders. The acute psychoactive effects of its main active ingredient, (-)-trans-Δ9-tetrahydrocannabinol (Δ9-THC), may be modulated by previous cannabis exposure. Secondary data analyses tested whether modest previous cannabis exposure modulated the acute effects of Δ9-THC on attentional salience and emotional...
Prescription opioid misuse among chronic pain patients is undergirded by self-regulatory deficits, affective distress, and opioid-cue reactivity. Dispositional mindfulness has been associated with enhanced self-regulation, lower distress, and adaptive autonomic responses following drug-cue exposure. We hypothesized that dispositional mindfulness might serve as a protective factor among...
(-) MDMA (0.3, 1.0, or 1.7 mg/kg) at 9 or 16 h (3 h before "lights off"). Morning treatments had no effects on sleep-like parameters. Racemic MDMA decreased general daytime activity during the first hour after injection and increased daytime activity at 3 hr posttreatment. Although afternoon administration of racemic MDMA increased sleep latency, it improved other sleep parameters, decreasing...
No medications are approved for cannabis use disorder (CUD). Gamma-aminobutyric acid (GABA) reuptake is modulated by cannabinoid (CB) receptor agonists, and there are shared effects between CB agonists and the GABA reuptake inhibitor tiagabine. This overlapping neuropharmacology suggested that tiagabine might be useful for CUD. The study determined the ability of tiagabine maintenance to reduce...
Rising interest in medical marijuana has prompted research into its phytocannabinoid constituents, particularly Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD). Coadministration of CBD with THC has been shown to modulate a number of THC's effects, including its negative stimulus properties (e.g., anxiety, paranoia, psychosis) in a clinical setting. The present series of experiments extended...
The glutamate hypothesis proposes that N-Methyl-D-aspartate (NMDA) receptor hypofunction underlies cognitive and perhaps other schizophrenic symptoms. The present study used the odor span task to assess the effects of NMDA antagonists on remembering multiple stimuli in rodents. This task uses an incrementing nonmatching-to-sample procedure in which responses to a new olfactory stimulus are...
Maladaptive decision-making is a cardinal feature of drug use, contributing to ongoing use, and reflecting alterations in how drug users assess uncertain reward value. Accumulating evidence indicates the consequences of heavy marijuana use are worse for female versus male animals and humans, but research assessing sex differences in reward-related decision-making among marijuana users remains...
Hallucinogens fall into several different classes, as broadly defined by pharmacological mechanism of action, and chemical structure. These include psychedelics, entactogens, dissociatives, and other atypical hallucinogens. Although these classes do not share a common primary mechanism of action, they do exhibit important similarities in their ability to occasion temporary but profound...