IMPORTANCE Cannabinoid drugs are widely used as analgesics, but experimental pain studies have produced mixed findings. The analgesic properties of cannabinoids remain unclear. OBJECTIVE To conduct a systematic review and meta-analysis of the association between cannabinoid drug administration and experimental pain outcomes in studies of healthy adults. DESIGN, SETTING, AND PARTICIPANTS A systematic search of PubMed, EMBASE, MEDLINE, PsycINFO, and CINAHL was conducted from the inception of each database to September 30, 2017. Studies were eligible for inclusion if they met criteria, including healthy participants and an experimentally controlled administration of any cannabinoid preparation in a quantified dose. Studies that used participants with chronic pain were excluded. Data extracted included study characteristics, cannabinoid types and doses, sex composition, and outcomes. Study quality was assessed using a validity measure previously established in published reviews. Random-effects meta-analyses were used to pool data and generate summary estimates. MAIN OUTCOMES AND MEASURES Experimental pain threshold, pain tolerance, pain intensity, pain unpleasantness, and mechanical hyperalgesia. RESULTS Eighteen placebo-controlled studies (with 442 participants) were identified. Of the 442 participants, 233 (52.7%) were male and 209 (47.3%) were female. For sample ages, 13 (72%) of the 18 studies reported a mean sample age (26.65 years), 4 (22%) reported a range, and 1 (6%) reported a median value. The search yielded sufficient data to analyze 18 pain threshold comparisons, 22 pain intensity comparisons, 9 pain unpleasantness comparisons, 13 pain tolerance comparisons, and 9 mechanical hyperalgesia comparisons. Cannabinoid administration was associated with small increases in pain threshold (Hedges g = 0.186; 95% CI, 0.054-0.318; P = .006), small to medium increases in pain tolerance (Hedges g = 0.225; 95% CI, 0.015-0.436; P = .04), and a small to medium reduction in the unpleasantness of ongoing experimental pain (Hedges g = 0.288; 95% CI, 0.104-0.472; P = .002). Cannabinoid administration was not reliably associated with a decrease in experimental pain intensity (Hedges g = 0.017; 95% CI, −0.120 to 0.154; P = .81) or mechanical hyperalgesia (Hedges g = 0.093; 95% CI, −0.059 to 0.244; P = .23). The mean quality rating across studies was good. CONCLUSIONS AND RELEVANCE Cannabinoid drugs may prevent the onset of pain by producing small increases in pain thresholds but may not reduce the intensity of experimental pain already being experienced; instead, cannabinoids may make experimental pain feel less unpleasant and more tolerable, suggesting an influence on affective processes. Cannabis-induced improvements in pain-related negative affect may underlie the widely held belief that cannabis relieves pain.

Research suggests one determinant of alcohol consumption may be physical pain, but there is no empirical evidence that pain has a causal effect on drinking. Therefore, the primary aim of this study was to test experimental pain as a determinant of several alcohol consumption proxies: self-reported urge to drink, intention to consume alcohol, and alcohol demand. This study also was designed to test negative affect as a mediator of the effects of pain on alcohol use proxies. We hypothesized that participants randomized to experimental pain induction (vs. no pain) would report greater urge, intention, and alcohol demand, and that these effects would be mediated by increased negative affect. Participants were healthy undergraduates who were moderate-heavy drinkers (N = 61). Experimental pain was induced using a novel capsaicin-heat model intended to approximate key features of clinical pain. Results indicated that participants in the pain condition subsequently endorsed greater urge and intention to drink. Furthermore, these effects were mediated by pain-induced negative affect. We observed no effect of pain on alcohol demand. This is the first study to demonstrate a causal effect of acute pain on urge and intention to drink. Given the close association between alcohol consumption, urge and intention to drink, these findings suggest that pain may influence alcohol consumption, which can have implications for individuals with co-occurring pain and alcohol use disorder (AUD). Specifically, individuals with co-occurring pain and AUD may drink to alleviate pain-related negative affect. Therefore, improving pain-coping skills may enhance pain-management abilities, subsequently reducing coping-motivated drinking. (PsycINFO Database Record

ABSTRACT. Objective: Alcohol use disorder (AUD) relapse is a construct that has been of major clinical and research interest but has been inconsistently defined. The purpose of this study was to review the definitions of AUD relapse that have been used in clinical research as a basis for drawing conclusions about its heuristic value. Method: A systematic review of the literature was conducted on empirical studies that (a) were published in peer-reviewed journals, (b) were published between 2010 and 2015, (c) were written in English, and (d) provided a definition of alcohol relapse (or lapse) that was used in the study. Results: The review yielded 139 individual studies that met inclusion criteria. The studies showed wide variability in how relapse was defined and interpreted in the literature, and there was little direct empirical or theoretical rationale provided for the definitions of relapse that were chosen. Furthermore, the concept of AUD relapse as a discrete state is not consistent with the empirical literature on the clinical course of alcohol consumption. Conclusions: We conclude that the heuristic value of AUD relapse as currently studied is low. An alternative approach that embeds the construct in theory and data on the clinical course of alcohol consumption and aligns with current trends in healthcare would seem to have a better chance of improving AUD clinical decision-making and knowledge about AUD in general. (J. Stud. Alcohol Drugs, 77, 849-858, 2016 T HE TERM RELAPSE is part of the common discourse with respect to addictive behaviors. For example, a simple Google search for either "relapse and addiction" or "relapse and alcohol" yields millions of results. The purpose of this article is to examine the use of the term relapse in the area of alcohol use/alcohol use disorder (AUD) change, whether by self-initiation, the use of mutual-help groups, formal treatment services, or some combination of the three. The ultimate goal of this line of inquiry is to appraise the heuristic value of the term relapse in advancing clinical research and treatment. Heuristic value in this article means value in aiding the discovery of knowledge about AUD clinical course through the generation of research. The article begins with an overview of conceptual definitions of AUD relapse followed by reporting the findings of a systematic review of recently published (2010)(2011)(2012)(2013)(2014)(2015) empirical studies that have included relapse as an independent or dependent variable. Definition of relapseAccording to the online edition of the Merriam-Webster Dictionary (n.d.), "relapse" is derived from the Latin word relabi, which means "to slide back." Relapse as a verb means "to become ill again after a period of improvement in health," or "to return to a bad condition, form of behavior, etc." The noun form of relapse simply means a return of illness or a return to a former and undesirable condition.The construct of relapse is often applied in reference to what typically are considered physical illnesses. In this conte...

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Background The construct of relapse is used widely in clinical research and practice of alcohol use disorder (AUD) treatment. The purpose of this study was to test the predictive validity of commonly appearing definitions of AUD relapse in the empirical literature. Method Secondary analyses of data from Project MATCH and COMBINE were conducted using 7 definitions of “relapse” based on drinking quantity within a single drinking episode: any drinking; at least 4/5 drinks for women/men; at least 4.3/7.1 drinks for women/men; at least 6/7 drinks for women/men; at least 6 drinks; at least 7/9 drinks for women/men; at least 8/10 drinks for women/men. Relapse was used to predict alcohol consumption, related consequences, and non-consumption outcomes (quality of life, psychosocial functioning) at end-of-treatment and up to 1 year post-treatment. Results Regression analyses indicated within-treatment relapse definitions significantly predicted end-of-treatment alcohol consumption and alcohol-related consequences. Heavy drinking definitions were generally more predictive than the any drinking definition, but no single heavy drinking definition was consistently a better predictor of outcomes. Relapse definitions were less predictive of longer-term alcohol-related outcomes and both shorter- and longer-term non-consumption outcomes, including health and psychosocial functioning. Conclusions One particular definition of relapse did not consistently stand out as the best predictor. Advances in AUD research may require reconceptualization of relapse as a multifaceted dynamic process and may consider a wider range of relevant behaviors (e.g., health and psychosocial functioning) when examining the change process in individuals with AUD.