John M. Light

A Proof-of-Concept Randomized Controlled Study of Gabapentin: Effects on Cannabis Use, Withdrawal and Executive Function Deficits in Cannabis-Dependent Adults

There are no FDA-approved pharmacotherapies for cannabis dependence. Cannabis is the most widely used illicit drug in the world, and patients seeking treatment for primary cannabis dependence represent 25% of all substance use admissions. We conducted a phase IIa proof-of-concept pilot study to examine the safety and efficacy of a calcium channel/GABA modulating drug, gabapentin, for the treatment of cannabis dependence. A 12-week, randomized, double-blind, placebo-controlled clinical trial was conducted in 50 unpaid treatment-seeking male and female outpatients, aged 18–65 years, diagnosed with current cannabis dependence. Subjects received either gabapentin (1200 mg/day) or matched placebo. Manual-guided, abstinence-oriented individual counseling was provided weekly to all participants. Cannabis use was measured by weekly urine toxicology and by self-report using the Timeline Followback Interview. Cannabis withdrawal symptoms were assessed using the Marijuana Withdrawal Checklist. Executive function was measured using subtests from the Delis–Kaplan Executive Function System. Relative to placebo, gabapentin significantly reduced cannabis use as measured both by urine toxicology (p=0.001) and by the Timeline Followback Interview (p=0.004), and significantly decreased withdrawal symptoms as measured by the Marijuana Withdrawal Checklist (p<0.001). Gabapentin was also associated with significantly greater improvement in overall performance on tests of executive function (p=0.029). This POC pilot study provides preliminary support for the safety and efficacy of gabapentin for treatment of cannabis dependence that merits further study, and provides an alternative conceptual framework for treatment of addiction aimed at restoring homeostasis in brain stress systems that are dysregulated in drug dependence and withdrawal.

Fundamental Principles of Network Formation among Preschool Children.

The goal of this research was to investigate the origins of social networks by examining the formation of childrens peer relationships in 11 preschool classes throughout the school year. We investigated whether several fundamental processes of relationship formation were evident at this age, including reciprocity, popularity, and triadic closure effects. We expected these mechanisms to change in importance over time as the network crystallizes, allowing more complex structures to evolve from simpler ones in a process we refer to as structural cascading. We analyzed intensive longitudinal observational data of childrens interactions using the SIENA actor-based model. We found evidence that reciprocity, popularity, and triadic closure all shaped the formation of preschool childrens networks. The influence of reciprocity remained consistent, whereas popularity and triadic closure became increasingly important over the course of the school year. Interactions between age and endogenous network effects were nonsignificant, suggesting that these network formation processes were not moderated by age in this sample of young children. We discuss the implications of our longitudinal network approach and findings for the study of early network developmental processes.

Proof-of-concept human laboratory study for protracted abstinence in alcohol dependence: effects of gabapentin

There is a need for safe medications that can effectively support recovery by treating symptoms of protracted abstinence that may precipitate relapse in alcoholics, e.g. craving and disturbances in sleep and mood. This proof‐of‐concept study reports on the effectiveness of gabapentin 1200 mg for attenuating these symptoms in a non‐treatment‐seeking sample of cue‐reactive, alcohol‐dependent individuals. Subjects were 33 paid volunteers with current Diagnostic and Statistical Manual of Mental Disorders‐IV alcohol dependence and a strength of craving rating 1 SD or greater for alcohol than water cues. Subjects were randomly assigned to gabapentin or placebo for 1 week and then participated in a within‐subjects trial where each was exposed to standardized sets of pleasant, neutral and unpleasant visual stimuli followed by alcohol or water cues. Gabapentin was associated with significantly greater reductions than placebo on several measures of subjective craving for alcohol as well as for affectively evoked craving. Gabapentin was also associated with significant improvement on several measures of sleep quality. Side effects were minimal, and gabapentin effects were not found to resemble any major classes of abused drugs. Results suggest that gabapentin may be effective for treating the protracted abstinence phase in alcohol dependence and that a randomized clinical trial would be an appropriate next step. The study also suggests the value of cue‐reactivity studies as proof‐of‐concept screens for potential antirelapse drugs.

Effect of positive and negative affective stimuli and beverage cues on measures of craving in non treatment-seeking alcoholics

RationaleLaboratory paradigms are useful for investigating mechanisms of human alcohol cue reactivity in a highly controlled environment. A number of studies have examined the effects of beverage exposure or negative affective stimuli on cue reactivity independently, but only a few have reported on interaction effects between beverage cue and affective stimuli, and none have evaluated the effects of positive stimuli on beverage cue reactivity.ObjectivesTo assess independent and interactive effects of both positive and negative affective stimuli and beverage cue on psychophysiological and subjective measures of reactivity in alcohol dependence.Materials and methodsA total of 47 non-treatment-seeking paid volunteers with current alcohol dependence participated in a within-subjects trial where each was exposed to a standardized set of pleasant, neutral, or unpleasant visual stimuli followed by alcohol or water cues. Psychophysiological cue-reactivity measures were obtained during beverage presentation, and subjective reactivity measures were taken directly following beverage presentation.ResultsMixed-effect models revealed a significant main effect of beverage and positive (but not negative) affective stimuli on subjective strength of craving and significant main effects of both positive and negative affective stimuli on ratings of emotionality. Despite the power to detect relatively small interaction effects, no significant interactions were observed between affect and beverage conditions on any reactivity measure.Conclusions A key finding of this study is that positive affective stimuli commonly associated with drinking situations can induce craving in the absence of alcohol cues. Main effects of beverage cue replicated results from previous studies. Beverage and affective cues showed no interaction effects.

Does substance use moderate the association of neighborhood disadvantage with perceived stress and safety in the activity spaces of urban youth

BACKGROUND This study investigates the association of activity space-based exposure to neighborhood disadvantage with momentary perceived stress and safety, and the moderation of substance use on those associations, among a sample of 139 urban, primarily African American, adolescents. METHOD Geospatial technologies are integrated with Ecological Momentary Assessment (EMA) to capture exposure to neighborhood disadvantage and perceived stress and safety in the activity space. A relative neighborhood disadvantage measure for each subject is calculated by conditioning the neighborhood disadvantage observed at the EMA location on that of the home neighborhood. Generalized estimating equations (GEE) are used to model the effect of relative neighborhood disadvantage on momentary perceived stress and safety, and the extent to which substance use moderates those associations. RESULTS Relative neighborhood disadvantage is significantly associated with higher perceived stress, lower perceived safety, and greater substance use involvement. The association of relative neighborhood disadvantage with stress is significantly stronger among those with greater substance use involvement. CONCLUSION This research highlights the value of integrating geospatial technologies with EMA and developing personalized measures of environmental exposure for investigating neighborhood effects on substance use, and suggests substance use intervention strategies aimed at neighborhood conditions. Future research should seek to disentangle the causal pathways of influence and selection that relate neighborhood environment, stress, and substance use, while also accounting for the role of gender and family and peer social contexts.

Investigating Social Support and Network Relationships in Substance Use Disorder Recovery

BACKGROUND Social support and characteristics of ones social network have been shown to be beneficial for abstinence and substance use disorder recovery. The current study explores how specific sources of social support relate to general feelings of social support and abstinence-specific self-efficacy. METHODS Data were collected from 31 of 33 individuals residing in 5 recovery houses. Participants were asked to complete social support and social network measures, along with measures assessing abstinence from substance use, abstinence self-efficacy, and involvement in 12-step groups. RESULTS A significant positive relationship was found between general social support and abstinence-specific self-efficacy. General social support was also significantly associated with the specific social support measures of sense of community and Alcoholics Anonymous (AA) affiliation. Social network size predicted abstinence-related factors such as AA affiliation and perceived stress. CONCLUSIONS These results provide insight regarding individual feelings of social support and abstinence-specific self-efficacy by showing that ones social network-level characteristics are related to ones perceptions of social support. We also found preliminary evidence that individual Oxford Houses influence ones feelings of social support.

Psychosocial Correlates of Physical and Sedentary Activities of Early Adolescent Youth

This study examines physical and sedentary activities of early adolescent boys and girls using Ecological Momentary Assessment (EMA), a method that can link mood and behaviors in specific social situations. Twenty-seven assessments were collected across 7 days from 82 participating adolescents, three times in seventh grade and one time in eighth grade. Assessments were completed during nonschool hours when youth had “free time.” Gender differences, longitudinal trends, and associations of physical activities (PA) and small screen recreation (SSR) with moods and peer presence are examined. Boys were engaged in PA more than girls. Patterns of PA differed by gender; boys significantly decreased PA from seventh to eighth grade, whereas girls had increased PA only during the spring. PA was associated with happier mood and was more likely to occur in the presence of peers. SSR significantly increased from seventh grade to eighth grade for both boys and girls. SSR occurred more when youth were alone and was not associated with mood. Neither PA nor SSR was more likely to occur during weekdays or weekends. Implications for intervention efforts to increase PA in youth are discussed.

Factors affecting the stability of social networks during early recovery in ex-offenders.

Abstract Background: Few studies have considered the retention of the individuals (alters) comprising the social networks of people in recovery. Objective: The purpose of this study was to describe factors predicting whether alters were retained 6 months after participants completed treatment. Method: The Important Person Inventory was given to 270 ex-offenders (224 men, 46 women) transitioning from treatment to Oxford House residences, Safe Haven therapeutic communities, or to usual aftercare. A 6-month follow-up was completed by 176 participants (137 men, 39 women). Results: We found that alters who were related to the participant, did not use drugs, were embedded in smaller networks, and had more frequent contact with the participant were significantly more likely to be retained as important people over 6 months. The alters’ drinking and criminal history were not significantly predictive of retention in the network. Conclusions: Certain characteristics of important people are related to their retention in a social network. Understanding these relationships and the extent to which the network change that occurs is aligned with abstinence-supporting networks is essential for creating effective social interventions for persons in recovery.

Influence of parent–youth relationship, parental monitoring, and parent substance use on adolescent substance use onset.

The quality of parent–child relationships likely influences many decisions and behaviors made by early adolescents, including their alcohol and marijuana use. We examined how parent–youth relationship quality, parental monitoring, and parent substance use were associated with initiation of alcohol use, binge drinking, and marijuana use by 400 adolescents by the spring of 8th grade (ages 13–14), and changes in initiation through 9th grade (assessed 3 times; fall, winter, and spring). We measured both parent and adolescent report of parent–youth relationship quality and parental monitoring, expecting that both perspectives would uniquely contribute. Discrete Time Survival models showed that youth report of both a poorer parent–youth relationship and lower parental monitoring were associated with alcohol use, binge drinking, and marijuana use onset. Parent binge drinking also predicted youth alcohol onset and parent report of poor quality relationship predicted marijuana onset. Youth report of a poor relationship with parents was a stronger predictor for girls than boys on their alcohol use onset, and youth report of parental monitoring was more protective for girls than boys for both alcohol and marijuana use onset. Implications for preventing use of these substances during early and mid-adolescence are discussed.

Legalization of Recreational Marijuana and Community Sales Policy in Oregon: Impact on Adolescent Willingness and Intent to Use, Parent Use, and Adolescent Use.

Studies investigating the impact of medical marijuana legalization have found no significant changes in adolescent use. In one of the few studies focused on recreational marijuana, we investigated how recreational marijuana legalization and community sales policy influenced factors that likely impact youth use (youth willingness and intent to use, parent use) as well as youth use. Legalization of recreational marijuana in Oregon coincided with our study on adolescent substance use. Cohort 1 transitioned from 8th to 9th grade prior to legalization and Cohort 2 made this transition during legalization (N = 444; 53% female). Communities were allowed to opt out of sales. Multivariate linear regression models estimated the impact of legalization and community sales policy on changes in attitudes and parent use (2 time points 1 year apart). Zero-inflated Poisson growth curve models estimated the effects on initial levels and rate of change from 8th through 9th grade (4 time points). In communities opting out of sales, the prior-to-legalization cohort was less likely to increase their willingness and intent to use marijuana, and the legalization cohort was more likely to increase intent to use. For youth who used marijuana, legalization was associated with increased use, and those in communities opting out of sales had greater growth in marijuana use. Community policy appears to impact youth attitudes toward, and use of, marijuana. Results suggest that legalization of recreational marijuana did not increase marijuana use for youth who did not use marijuana but did increase use in youth who were already using.