The opioid crisis continues to devastate individuals, families, and communities across Canada. In 2016-19, more than 13,900 opioid-related deaths occurred in Canada. Dangerous patterns of prescription opioid use (e.g., using a prescribed opioid without a prescription, outside of its intended purposes, or in excessive quantities) remain a major health threat. Opioids were prescribed to 12.3% of Canadians in 2018. Non-medical use of prescription opioids is markedly higher in Canada/US than elsewhere in the world. Prescription opioids pose an addiction risk of \~5.5% and cost Canadians \~$3.5 billion in healthcare, productivity, and justice costs pre-pandemic. They also pose a threat through the danger of death by overdose. Rates of hospitalization due to opioid poisoning have increased by 27% in the past 5 years, signaling a worsening of the crisis. Opioid-related mortality had been on a steady rise, reaching epidemic proportions pre-pandemic. Overdose rates have increased 5-fold over the past 20 years. Opioid-related deaths have only increased since the COVID-19 pandemic due to the economic downturn and to disruptions to the drug supply chain through border closures. This has resulted in the use of cheaper and more dangerous substances like the powerful synthetic opioids fentanyl and carfentanyl. Pre-pandemic data link fentanyl with 72% of accidental opioid-related deaths in Canada, an 81% increase from the year prior. Street drugs (e.g., heroin, cocaine) are also increasingly being cut with the cheaper fentanyl, leading to a surge in accidental overdoses. Only 0.08% of seized heroin samples tested positive for fentanyl in 2012, whereas 60.1% tested positive in 2017 - an enormous increase in 5 years. Given the progression and escalation of the opioid crisis, opioid use disorder (OUD) is now one of the greatest challenges facing the Canadian health care system, compounded by the COVID-19 pandemic.

Treatment for OUD generally involves pharmacological treatments such as opioid agonist therapy (OAT) including buprenorphine-naloxone and methadone, both of which are efficacious in treating OUD and widely used in Canada. Rooted in a harm-reduction approach, those undergoing OAT are administered a synthetic opioid agonist, under specific controlled dosages. After stabilization, both methadone and buprenorphine/naloxone have shown efficacy for suppressing opioid use, with higher doses being more effective. More recently, alternative OAT treatment modalities including slow-release oral morphine (Kadian) and injectable opioid agonist therapy (iOAT) have been approved for use in opioid addiction medicine within Canada. OAT is effective at reducing opioid use, overdoses, HIV risk, and criminality.

Limitations of OAT: Unfortunately, OAT alone fails to address other problems common in those with OUD. Clients on OAT frequently present with concurrent use of numerous drugs and with high rates of comorbid alcohol, anxiolytic/sedative, stimulant (cocaine/amphetamines), and cannabis use disorders. As a harm reduction treatment, OAT reduces opioid use; but it does not eliminate all opioid use in all OUD clients. OAT clients' polysubstance use includes risky drug combinations, such as opioids (including methadone) plus benzodiazepines (BZs; a class of sedative/anxiolytic), which greatly increases overdose risk, and interferes with optimal treatment outcomes . Experts recommend avoiding concurrent BZ-opioid prescriptions as one of the main ways to combat the opioid crisis . Some individuals in OAT also continue frequently using other drugs such as alcohol, cannabis, and cocaine, including via injection - a particularly risky administration route . Co-use of alcohol and methadone increases overdose risk and negatively impacts cognitive performance and daily functioning. While findings are mixed, recent studies caution that concurrent cannabis use predicts poorer OAT response. Stimulant co-use predicts HIV risk (stimulants are often injected) and poorer OAT retention . Previous research in three studies (60-138 clients per study) at six clinics across Nova Scotia, New Brunswick, \& Quebec, highlight the very high rates of polysubstance use in OAT clients . A consistent finding was the very high endorsement of recent polysubstance use, while clients were on OAT: 29% 'topped up' their OAT with another opioid, 27.5% injected drugs, and 54% used BZs despite their well-documented overdose risk with OAT. While OAT has had positive harm reduction effects for OUD, adjunct psychosocial approaches may curb polysubstance use, increase OAT retention, and reduce overdose, providing new solutions to the opioid crisis.

Psychosocial Treatments Supplementing OAT: Psychosocial treatments for substance use disorder (SUD) employ many techniques, including contingency management, relapse prevention, cognitive behavior therapy (CBT), motivational interviewing, and 12-step facilitation. A recent systematic review showed supplementing OAT with psychosocial interventions led to greater treatment attendance, psychological functioning, and adherence to psychiatric medications, and decreased opioid use, alcohol use, and HIV risk. Recent Canadian guidelines for managing OUD released by Canadian Research Initiative on Substance Misuse (CRISM) network, strongly endorse adding psychosocial treatment options to pharmacological interventions, and advocate exploring additional non-pharmacotherapy interventions to supplement OAT. The Opioid Task force of the Canadian Psychological Association recently made similar recommendations and called for increased research in this area to fill important gaps in knowledge around psychosocial and harm reduction interventions that work well in combination with OAT. Despite the availability of psychosocial treatments to supplement OAT, rates of concurrent polysubstance use remain exceedingly high among OAT clients. OAT clinics feel unprepared to deal with complex psychiatric comorbidity and the effective psychosocial interventions require training backgrounds that are not often practical in OAT clinics (e.g., minimum Masters' degree in a mental health field to practice CBT . Interventions that specifically and effectively target concurrent polysubstance use and psychiatric comorbidity are needed to improve OAT retention, particularly those that are developed using a patient-oriented approach to increase their acceptability to patients and are practical for application by OAT service providers to ensure their sustainability in clinics.

Personality Model of Substance Use \& Intervention Development: An efficacious and effective protocoled, psychosocial intervention for targeting polysubstance use over the past few decades has been developed, \] and is adaptable to the OAT context providing a possible avenue for additional, acceptable, and sustainable psychosocial treatment that effectively targets clients' dangerous concurrent polysubstance use to improve OAT retention. The personality model of substance use posits that individual differences in substance use patterns are explained by differential sensitivity to the reinforcing effects of alcohol and other drugs, based on functionally distinct motivational systems that are manifested as different traits. Substance use behaviors can therefore be understood through two broad domains of personality - the disinhibited (i.e., externalizing) and inhibited (i.e., internalizing) domains - which in turn can be broken down into four lower-order personality traits that are intimately linked with substance use. Elevations on these four personality traits have been shown to predict risk for using specific substances, differential motivational profiles for substance use , differential sensitivity to the pharmacological effects of various drugs, and vulnerability to co-morbid psychiatric disorders.

Using a combination of motivational enhancement and cognitive-behavioral skills-building via in-session group activities and homework, these interventions target specific personality-relevant cognitive distortions (see below) and have been repeatedly shown to delay or reduce alcohol and other substance use by 30-80% among high-risk youth.

Within the disinhibited domain, lower-order personality traits associated with substance use are sensation seeking (SS; novelty/pleasure seeking) and impulsivity (IMP; disinhibited personality). Within the inhibited domain, lower-order traits associated with substance use are anxiety sensitivity (AS; fear of arousal) and hopelessness (HOP; depression proneness). These traits can be quickly measured with the widely validated, and internationally used Substance Use Risk Profile Scale (SURPS). Within the four-factor model of substance use, sensation seeking is characterized by a preference for novel and exciting activities, and by boredom proneness.

A Framework for Validation, Intervention Adaptation and Testing: Due to the clear need for more effective psychosocial interventions to supplement OAT for addressing OUD and related morbidity, the ongoing high rates of polysubstance use among OAT clients, and extremely high rates of OAT dropout, PreVenture and CoVenture has been adapted to OUD clients in the OAT clinic context, and is being called "OpiVenture". The framework underlying OpiVenture's development is the U.S. National Institute of Health's (NIH's) ORBIT model for psychosocial and behavioral treatment development. This evidence-based framework centers around a stakeholder-informed significant clinical research question: "How can dangerous patterns of polysubstance use be curbed and how can OAT retention improve to reduce morbidity and mortality?" The ORBIT model provides guidance through four phases for improving the systematic development, adaptation, and testing of appropriately designed and innovative psychosocial interventions. In Phase I, the intervention is designed based on evidence from basic behavioral and psychosocial research and stakeholder input. In Phase II, preliminary testing of the intervention takes place (e.g., feasibility studies). It is only after Phases I-II that one proceeds on to Phases III-IV: Efficacy (RCTs) and Effectiveness (trials under real world conditions), returning to earlier phases for refinement as necessary. A patient-oriented integrated knowledge translation (iKT) approach is embedded throughout to ensure that developed interventions are acceptable to patients and practitioners.

Phase I of OpiVenture development has been completed investigating the role of personality in the maintenance of substance use among OAT clients, validating the four-factor personality model in this client demographic. Using qualitative interview data focused on clients' understanding of their personality, substance use patterns, contexts, and triggers for their substance use, has informed the adaptation of existing personality-targeted intervention manuals. Additionally, focus groups with OAT clinic service providers and staff informed intervention delivery format, including ideal contextual parameters such as scenarios and session lengths.