Invariant Measures for Hybrid Stochastic Systems

In this paper, we seek to understand the behavior of dynamical systems that are perturbed by a parameter that changes discretely in time. If we impose certain conditions, we can study certain embedded systems within a hybrid system as time-homogeneous Markov processes. In particular, we prove the existence of invariant measures for each embedded system and relate the invariant measures for the various systems through the flow. We calculate these invariant measures explicitly in several illustrative examples.Comment: 18 pages, 7 figure

Preliminary Efficacy of Motivational Interviewing on Problem Drinkers 55 and Older compared to Younger Counterparts

Background: Older adults who drink problematically are the largest group of substance users among those 55 and older. This group often chooses moderation as a goal instead of abstinence, and motivation and self-efficacy are found to have less of an impact on drinking compared to younger adults. No study has examined age effects (specifically 55 and older vs. younger counterparts) on motivational interviewing (MI) compared to brief advice with a sample that includes individuals over 65. Objective: To explore the moderating impact of age on heavy drinkers’ (aged M=50.7 years SD=11.6, range 23-73) response to MI. Methods: Data were from a randomized controlled trial testing stepped care brief interventions for alcohol use disorder. Participants were: 97 aged 22 - 54 years and 66 aged 55-73 years. For this study, generalized estimating equations were used to test drinks per drinking day (DDD) 4 weeks after 2 sessions of MI were implemented compared to brief advice alone. Results: There was no main effect of continuous age on DDD; however, individuals 55 and older demonstrated significantly lower DDD at week 8 than their younger counterparts (on average .20 of standard drink, B=-.17, SE=.07,

The independent relationship between trouble controlling Facebook use, time spent on the site and distress

Background and Aims There is an emerging literature base on the relationship between maladaptive traits and “addiction” to social networking sites. These studies have operationalized addiction as either spending excessive amounts of time on social networking sites (SNS) or trouble controlling SNS use, but have not assessed the unique contribution of each of these constructs on outcomes in the same models. Moreover, these studies have exclusively been conducted with younger people rather than a heterogeneous sample. This study examined the independent relationship of a brief Facebook addiction scale, time spent on Facebook, and Facebook checking on positive and negative social domains, while controlling for self-esteem and social desirability. Methods Participants were recruited using e-mail, SNS posts and through Amazon’s MTurk system. The sample included 489 respondents ages from 18 to approximately 70, who completed a 10–15 minute survey. Results Results indicate that neither time spent on Facebook nor Facebook checking was significantly associated with either self-esteem, fear of negative social evaluation or social comparison, while SNS addiction symptoms were each independently associated with Facebook usage. Neither time spent on Facebook nor SNS addiction symptoms were associated with positive social relationships. Discussion Overall results suggest that time on SNS and trouble controlling use should be considered independent constructs and that interventions should target underlying loss of control as the primary intervention target above ego syntonic time spent on the site

Exploration of Treatment Matching to Problem Drinker Characteristics With Motivational Interviewing and Non-directive Client-centered Psychotherapy for Problem Drinkers

Motivational Interviewing (MI) is a known effective intervention for alcohol use disorder (AUD). MI\u27s mechanisms of action remain inconsistently substantiated, and research in this area has been reliant on identifying relationships through strength of association rather than experimental manipulation of active ingredients. In two previous studies, a pilot and a larger replication study, we disaggregated MI into its hypothesized active ingredients by creating three conditions: MI, Spirit Only MI (SOMI, in which evocation of change talk was proscribed), and a non-therapy condition (NTC). Results from both studies yielded equivalent findings across all three conditions. In the current analyses, data from both studies were combined to test five participant characteristics as moderators of MI\u27s component parts: 1) severity of baseline drinking, 2) severe AUD (met 6 or more criteria), 3) baseline self-efficacy to moderate drinking, 4) mean daily confidence to resist heavy drinking in the week prior to treatment initiation, and 5) depression. There were no significant findings related to baseline drinking, severe AUD, or baseline self-efficacy. Confidence yielded a significant interaction effect. When participants had high baseline confidence, drinking for those in MI increased compared to those in SOMI. Depression also yielded a significant moderating effect such that in the context of higher depressive symptoms, receipt of either therapy reduced drinking relative to NTC. Results are discussed in light of existing literature on MOBC with MI and the potential role exploring ambivalence may play for participants with particular characteristics

A randomized controlled pilot trial of different mobile messaging interventions for problem drinking compared to weekly drink tracking

This study was supported by a grant from the National Institute on Alcohol Abuse and Alcoholism (NIAAA) R34AA021502. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Dismantling Motivational Interviewing: Effects on Initiation of Behavior Change Among Problem Drinkers Seeking Treatment

Motivational Interviewing (MI) is an efficacious treatment for alcohol use disorders (AUD). MI is thought to enhance motivation via a combination of two therapeutic strategies or active ingredients: one relational and one directional. The primary aim of this study was to examine MI’s hypothesized active ingredients using a dismantling design. Problem drinkers (N=139) seeking treatment were randomized to one of three conditions: MI, relational MI without the directional elements labeled spirit-only MI (SOMI) or a non-therapy control (NTC) condition and followed for eight weeks. Those assigned to MI or SOMI received four sessions of treatment over eight weeks. All participants significantly reduced their drinking by week 8, but reductions were equivalent across conditions. The hypothesis that baseline motivation would significantly moderate condition effects on outcome was generally not supported. Failure to find support for MI s hypothesized active ingredients is discussed in the context of the strengths and limitations of the study design

Testing Cross-sectional and Prospective Mediators of Internalized Heterosexism on Heavy Drinking, Alcohol Problems, and Psychological Distress Among Heavy Drinking Men Who Have Sex with Men

Objective: Minority stress theory is often used as a causal explanation for substance use among lesbian, gay, and bisexual populations. This study tested whether drinking to cope with stress (DTC), loneliness, and gay community participation (GCP) mediated the relationship between one type of minority stress (i.e., internalized heterosexism, IH) and behavioral health outcomes. Method: Utilizing secondary data analysis and the PROCESS procedure, relationships between IH, the mediators (DTC, loneliness, and GCP), and outcomes (heavy drinking, alcohol problems, and psychological distress) were explored, both cross-sectionally and in a lagged manner, among both treatment seeking and non-treatment seeking problem drinking men who have sex with men (MSM). Problem drinkers (N=187) were assessed, provided brief normative feedback about their drinking, given the choice to receive brief alcohol use disorder treatment or change on their own, and then followed for 9 months. Results: Cross-sectional findings revealed that IH was significantly associated with heavy drinking, alcohol problems, and psychological distress. DTC emerged as a significant mediator of IH for all the health outcomes. Loneliness and GCP were significant mediators of IH for alcohol problems and psychological distress. Multiple mediation models reveal that all three mediators significantly contribute to IH’s effect on health outcomes. Lagged analyses did not yield any significant indirect effects. Conclusion: Findings underscore the necessity of addressing IH in psychosocial interventions along with coping skills training that emphasizes culturally relevant social support. Limitations related to generalizability and measurement are reviewed

Within-person Associations Between Daily Motivation and Self-efficacy and Drinking Among Problem Drinkers in Treatment

Gaining a better understanding of the change process holds promise to improve alcohol treatment. Ecological momentary assessment (EMA) coupled with intensive longitudinal data (ILD) approaches have been proposed as promising methods that can advance change process research but have been used infrequently in AUD treatment research. The current study used these approaches to examine the within-person associations of motivation and self-efficacy and drinking among treatment seeking problem drinkers. Participants (N=96) received daily EMA surveys before, during, and after treatment for seven weeks spread over a nine month period. Multi-level modeling was used to test the within-person relationships between the change processes and drinking, controlling for between-person associations and prior drinking. Results indicated that daily fluctuations in motivation and self-efficacy significantly predicted drinking over the next 24 hours; however, several theory-driven hypotheses regarding factors that might moderate that relationship were not supported. Overall, results support the advantages of EMA and ILD as methods that can advance AUD treatment research

Dynamic systems modeling to identify a cohort of problem drinkers with similar mechanisms of behavior change

One challenge to understanding mechanisms of behavior change (MOBC) completely among individuals with alcohol use disorder is that processes of change are theorized to be complex, dynamic (time varying), and at times non-linear, and they interact with each other to influence alcohol consumption. We used dynamical systems modeling to better understand MOBC within a cohort of problem drinkers undergoing treatment. We fit a mathematical model to ecological momentary assessment data from individual patients who successfully reduced their drinking by the end of the treatment. The model solutions agreed with the trend of the data reasonably well, suggesting the cohort patients have similar MOBC. This work demonstrates using a personalized approach to psychological research, which complements standard statistical approaches that are often applied at the population level