Escape from stimuli correlated with transitions across lean and rich schedules of reinforcement

On a multiple-schedule of reinforcement, when a rich component is followed by a relatively lean component, responding is interrupted by extended pausing. The present experiment examined whether the discriminative stimulus correlated with this rich to lean transition acquired aversive properties. Four pigeons were exposed to a compound schedule with two fixed-ratio components programmed on the center key. One component ended with the delivery of a rich reinforcer (7-s access to grain) and the second with a lean reinforcer (1-s access). Each component was correlated with a distinctive key color. At the beginning of some components, a side key was activated. A single peck on this stimulus termination key replaced the discriminative stimulus on the center key with a white light regardless of whether the ongoing component was rich or lean. As in previous research, pausing was a joint function of the past and upcoming conditions of reinforcement and the FR requirement. At relatively large ratios, if the upcoming reinforcer was rich, pauses were short regardless of the past reinforcer. If the upcoming reinforcer was lean, pauses were longer and the length was directly influenced by the past reinforcer; the longest pauses were observed in the transitions from a rich to a lean reinforcer. At larger ratios, removal of the multiple-schedule stimuli occurred most often in the presence of a stimulus signaling a lean reinforcer and rarely in the presence of a stimulus signaling a rich reinforcer. The past reinforcer affected the frequency of escape for two pigeons (P822 and P830); they most often terminated the lean stimulus when it was preceded by a rich reinforcer

The application of digital health to the assessment and treatment of substance use disorders: The past, current, and future role of the National Drug Abuse Treatment Clinical Trials Network

The application of digital technologies to better assess, understand, and treat substance use disorders (SUDs) is a particularly promising and vibrant area of scientific research. The National Drug Abuse Treatment Clinical Trials Network (CTN), launched in 1999 by the U.S. National Institute on Drug Abuse, has supported a growing line of research that leverages digital technologies to glean new insights into SUDs and provide science-based therapeutic tools to a diverse array of persons with SUDs. This manuscript provides an overview of the breadth and impact of research conducted in the realm of digital health within the CTN. This work has included the CTN\u27s efforts to systematically embed digital screeners for SUDs into general medical settings to impact care models across the nation. This work has also included a pivotal multi-site clinical trial conducted on the CTN platform, whose data led to the very first “prescription digital therapeutic” authorized by the U.S. Food and Drug Administration (FDA) for the treatment of SUDs. Further CTN research includes the study of telehealth to increase capacity for science-based SUD treatment in rural and under-resourced communities. In addition, the CTN has supported an assessment of the feasibility of detecting cocaine-taking behavior via smartwatch sensing. And, the CTN has supported the conduct of clinical trials entirely online (including the recruitment of national and hard-to-reach/under-served participant samples online, with remote intervention delivery and data collection). Further, the CTN is supporting innovative work focused on the use of digital health technologies and data analytics to identify digital biomarkers and understand the clinical trajectories of individuals receiving medications for opioid use disorder (OUD). This manuscript concludes by outlining the many potential future opportunities to leverage the unique national CTN research network to scale-up the science on digital health to examine optimal strategies to increase the reach of science-based SUD service delivery models both within and outside of healthcare

Avoidance of Timeout from Response-Independent Schedules of Food or Sucrose Water with and without a Limited Hold on Consumption

Research on the relative aversiveness of timeout from lean and rich schedules of food delivery has yielded discrepant findings. Some research has shown that a lean schedule maintains higher avoidance response rates than a rich schedule (Thomas, 1964, 1965b; van Haaren & Anderson, 1998)---suggesting that timeout from a lean schedule is more aversive than timeout from a rich schedule---while other research has shown the opposite (D\u27Andrea, 1971; Richardson & Baron, 2008). The present study was based on the notion that the conflicting results may have arisen from differences in procedural details that influenced the effect of the food schedules on behavior that may compete with avoidance. At issue was whether a limited hold on consumption increases attending to the magazine (i.e., the site of food delivery) and decreases avoidance. When a limited hold is present, behavior directed toward the magazine may compete with avoidance, and thus compromise the validity of avoidance response rates as a measure of the aversiveness of timeout. When a limited hold is absent, competition between magazine-directed behavior and avoidance responding should be reduced, allowing avoidance response rates to serve as a valid measure of the aversiveness of timeout. Sixteen rats pressed a lever to avoid a 30-s timeout from a schedule of free food deliveries. Across conditions, the food deliveries--- either pellets or sucrose water---were arranged on a response-independent basis according to different variable-time (VT) schedules. The VT schedule parameter was 0.5-min, 1-min, 2-min, 4-min, and 8-min. A timeout was programmed whenever 30 s elapsed without a lever press. In Experiment 1, the Limited Hold conditions involved presentation of a dipper of sucrose water for a fixed duration. The Unlimited Hold conditions involved delivery of pellets. Because each pellet remained in the magazine until the rat retrieved it, there was no limited hold on consumption. In Experiment 1, manipulation of the presence or absence of a limited hold was confounded by the item delivered. Experiment 2 was designed to address this confound; sucrose water was delivered in every condition. In some conditions, the sucrose water deliveries incorporated a limited hold as in Experiment 1: The dipper was raised for a fixed duration. In other conditions, the dipper remained in a raised position until the rat\u27s head entered and exited the magazine as detected by a photocell. Regardless of whether a limited hold was present or absent, the rate of avoidance increased as the rate of food delivery was raised. This indicates that the aversiveness of timeout from a schedule of free food delivery is directly related to the richness of the schedule

Practical technology for expanding and improving substance use disorder treatment: telehealth, remote monitoring, and digital health interventions.

The US opioid crisis and the COVID-19 pandemic have sparked innovation in substance use disorder (SUD) treatment such that telehealth, remote monitoring, and digital health interventions are increasingly feasible and effective. These technologies can increase SUD treatment access and acceptability, even for nontreatment seeking, remote, and underserved populations, and can be used to reduce health disparities. Overall, digital tools will likely overcome many barriers to delivery of evidence-based behavioral treatments such as cognitive behavioral therapy and contingency management, that, along with appropriate medications, constitute the foundation of treatment of SUDs

Effects of incentivizing viral suppression in previously incarcerated adults living with HIV

Background: The amount of HIV in a person’s blood can be suppressed to an undetectable level through antiretroviral therapy medications (ART). Adhering to an ART regimen can improve a person’s health and reduce HIV transmission. Despite these benefits, many people with HIV do not maintain the level of adherence required to achieve an undetectable viral load. This problem is particularly common among people who have been incarcerated. Objective: To determine effects of incentivizing viral suppression in previously incarcerated adults with HIV. Methods: Adults with HIV (N = 102) and detectable viral load (>200 copies/mL) were randomly assigned to a Usual Care or Incentive group. Usual Care participants did not earn incentives for viral suppression. Incentive participants earned incentives ($10/day maximum) for providing blood samples with a reduced or undetectable (<200 copies/mL) viral load. Assessments were conducted every 3 months. Results collected during the first year were aggregated and compared based on group assignment and incarceration history. Results: Previously incarcerated participants in the Incentive group provided more (OR: 2.9; CI: 1.3-6.8; p <.05) blood samples with an undetectable viral load (69%) than those in the Usual Care group (41%). Never-incarcerated participants in the Incentive group provided more (OR: 6.8; CI: 2.2-21.0; p <.01) blood samples with an undetectable viral load (78%) than those in the Usual Care group (36%). Effects of incentives did not differ by incarceration history. Conclusions: Incentivizing viral suppression can increase viral suppression (undetectable viral load) in people who have been incarcerated

Towards detecting cocaine use using smartwatches in the NIDA clinical trials network: Design, rationale, and methodology

Cocaine use in clinical trials is often measured via self-report, which can be inaccurate, or urine drug screens, which can be intrusive and burdensome. Devices that can automatically detect cocaine use and can be worn conveniently in daily life may provide several benefits. AutoSense is a wearable, physiological-monitoring suite that can detect cocaine use, but it may be limited as a method for monitoring cocaine use because it requires wearing a chestband with electrodes. This paper describes the design, rationale, and methodology of a project that seeks to build upon and extend previous work in the development of methods to detect cocaine use via wearable, unobtrusive mobile sensor technologies. To this end, a wrist-worn sensor suite (i.e., MotionSense HRV) will be developed and evaluated. Participants who use cocaine (N = 25) will be asked to wear MotionSense HRV and AutoSense for two weeks during waking hours. Drug use will be assessed via thrice-weekly urine drug screens and self-reports, and will be used to isolate periods of cocaine use that will be differentiated from other drug use. The present study will provide information on the feasibility and acceptability of using a wrist-worn device to detect cocaine use