Innovative addiction research program: Addressing polysubstance use

British Columbia (BC) faces a mental health and addiction crisis with an estimated cost of $100 million annually. In April 2016, a public health emergency was declared due to an alarming increase in opioid-related overdose deaths in recent years.

People who use illicit drugs (PWUD) bear a great burden of preventable morbidity and mortality from drug overdoses as well as other comorbidities including mental disorders and infectious diseases. While opioid agonist therapies (OAT) have proven effective in reducing heroin use, concomitant use of opioids and stimulant drugs (e.g., heroin and cocaine) is common among PWUD. Furthermore, recent research has suggested that many PWUD also suffer from untreated chronic pain, which may be driving prescription opioid (PO) misuse among this population. However, little is known about patterns of concomitant use of illicit opioids, POs and stimulants, and how OAT and other health services may serve to mitigate potential harms associated with such polydrug use. Currently, no approved pharmacotherapies exist for stimulant use disorder, necessitating urgent research effort in this area.

Dr. Hayashi's research will inform policies, programs and clinical practice to reduce harms associated with polydrug use. The primary research objectives are:

• To investigate and address the impact of PO misuse, untreated chronic pain and concomitant opioid and stimulant use on patterns of drug-related harm.
• Evaluate "naturally occurring" interventions and policy changes (i.e., new opioid addiction-related services and Vancouver Coastal Health's Downtown Eastside Second Generation Strategy) that are relevant to polydrug users.
• Evaluate the efficacy of a novel pharmacotherapy to treat polydrug users. 

The research will employ vast longitudinal behavioural and biological data collected since 1996 via three ongoing prospective cohort studies of over 3000 PWUD in Vancouver. The findings are expected to inform care development and overdose prevention efforts for a high needs population in BC. One objective will involve implementing a clinical trial to evaluate whether an amphetamine-based medication reduces powder/crack cocaine use among 130 patients on OAT, who have both opioid and cocaine use disorders. If the study medication proves effective, Dr. Hayashi's research will potentially contribute to the identification of the first proven medication for cocaine addiction.