Prevalence of illicit substance use among patients presenting to the emergency department with acute behavioural disturbance: Rapid point‐of‐care saliva screening

OBJECTIVE: To determine the prevalence of illicit substance use among patients presenting to one ED with acute behavioural disturbance using point-of-care saliva testing. METHODS: A prospective observational study was conducted. Acute behavioural disturbance was defined as any episode requiring a security response for unarmed threat (Code Grey). The setting was a single ED and tertiary referral centre located in metropolitan Australia. Participants were adults presenting to the ED requiring a Code Grey. Saliva was analysed for meth/amphetamine, cannabis, cocaine and opiates using a rapid point-of-care test. Self-reported drug use was recorded at the time of saliva testing. Data collection occurred between August 2016 and March 2017. RESULTS: There were 229 valid saliva samples. Participants were, on average, 35 years (range 18-72) and male (168/229; 73%). Forty percent (95% confidence interval 34-47) of samples tested positive, with 20% positive for two or more substances. Meth/amphetamines was detected in 92% of positive samples, 17% of samples tested positive for opiates, 8% for cannabis and 7% for cocaine. Among participants, 19% self-reported current substance use and 20% reported using illicit substances within the past 24 h. CONCLUSIONS: The prevalence of illicit substance use among this cohort was 40%. Self-reporting was unreliable. Point-of-care saliva testing is feasible. Early identification of harmful drug use may assist clinical decision making in selected or undifferentiated cases and provide an opportunity to implement harm minimisation strategies and make referrals.