Our Current Projects
Sleep and Substance Use
Orexin receptors play a role in the regulation of sleep and wakefulness. They may also play a role in stress and substance use behaviors. Orexin receptors may influence opioid use through alternative pathways (e.g. improved sleep, reduced drug motivation). This project looks at the effects of an antagonist of these receptors (suvorexant) and how this medication impacts opioid abstinence in patients with opioid use disorder. This project will enable us to determine whether resolving disturbances in sleep (restoration of sleep efficiency) is important in reducing opioid use/relapse. Dr. Greenwald is contributing to a similar clinical trial in Sweden, anticipated to start in late 2024/early 2025.
Review paper: At the intersection of sleep deficiency and opioid use: mechanisms and therapeutic opportunities
Transcranial Magnetic Stimulation
Repetitive transcranial magnetic stimulation (rTMS) can be used to modify a variety of neural functions. Stimulation at frontal-cortical sites (dorsolateral prefrontal and medial prefrontal) can be used to alter executive function and stress-induced behavior, including drug-seeking behavior. We are studying these effects of this form of neuromodulation in persons with opioid use disorder.
Additional forms of neuromodulation (e.g. tACS, tDCS, photobiomodulation) will also be tested in the near future.
Contingency Management
Contingency management (CM) treatments are efficacious in improving behavioral outcomes and reducing substance use. In CM treatments, patients are rewarded for successfully meeting certain behavioral outcomes (e.g. 1 week of smoking abstinence, taking medication reliably). We explore a variety of ways that CM can be used in substance use treatment.
Publications:
1) Contingency management interventions for tobacco and other substance use disorders in pregnancy
Stress and Substance Use
Stress can increase and/or maintain drug seeking and use in laboratory animal and there is evidence to suggest it has the same impact in humans; however, until now there have been no well-controlled human studies to explore how stress impacts substance use. We seek to understand how stress impacts use of opioids in people who are currently using opioids.
Selected Publications:
Polysubstance Use
Epidemiological studies suggest greater health risks among opioid users who also use sedating substances (e.g. alcohol, benzodiazepines). Our research indicates that consequences of chronic heroin use are greater among non-medical (but not prescription) sedative users. We are using neurocognitive testing to understand how opioid/sedative polydrug users differ from primary opioid users (controlling for other substance use and psychiatric co-factors).
Selected Papers:
1) Factors associated with sedative use and misuse among heroin users
Cannabis Use, Cues, and Craving
Cannabis use can occur in a variety of situations and there are often cues that may cause a person to feel craving to use cannabis. Our lab explores cannabis use and craving and examines the effects of drug cue-exposure on cannabis-seeking behavior in regular cannabis users.
Selected Papers:
2) Beyond the Bud: Emerging Methods of Cannabis Consumption for Youth
Problem and Disordered Gambling
Problem and disordered gambling can have a significant impact on a person’s life. We research factors associated with problem gambling and interventions to help people who are experiencing a problem with gambling.
Selected Publications:
2) Gambling-Related Cognitive Distortions in Residential Treatment for Gambling Disorder
Substance Use Consequences
Consequences from chronic substance use may be driven by pre-existing factors, and may influence current functional status. Yet, inter-relationships among impulsivity, drug-use consequences and mood/stress are poorly understood.
Selected Publications:
1) Developing a scale of domains of negative consequences of chronic heroin use
2) Mediational pathways among trait impulsivity, heroin-use consequences, and current mood state
Naloxone Access & Use
Consequences from chronic substance use may be driven by pre-existing factors, and may influence current functional status. Yet, inter-relationships among impulsivity, drug-use consequences and mood/stress are poorly understood
Self-Medication For People With Substance Use Disorders
There are a variety of complicated reasons that people choose to use illicit substances or misuse prescription medications. We are working to elucidate some of the motivations behind use of different substances in people with opioid use disorder.
Neuroimmune System
The neuroimmune system, principally composed of microglia and astrocytes, may be disrupted by chronic substance use. Further, recent evidence suggests that disruption to the neuroimmune system may contribute to the development and/or perpetuation of substance use disorders, and thus, may be a therapeutic target. Ongoing research in our lab is investigating the role of the neuroimmune system, using multimodal in vivo neuroimaging, in opioid use disorder, cigarette smoking, and chronic pain.