A multicenter retrospective survey of poisoning after consumption of products containing novel psychoactive substances from 2013 to 2014 in Japan

<i>Background</i>: In Japan, fatalities among patients who experienced an acute reaction following self-administration of novel psychoactive substances (NPS) have been more frequently reported since June 2014. <i>Objective</i>: This survey aimed to document and analyze trends in NPS consumption in emergency patients. <i>Methods</i>: We conducted a multicenter retrospective survey of patients who were transported to emergency facilities after consuming NPS-containing products between January 2013 and December 2014. Letters requesting participation were sent to 467 emergency facilities, and questionnaires were mailed to facilities that agreed to participate. <i>Results</i>: We surveyed 589 patients from 85 (18.2%) facilities. Most patients were male (89.6%) and young (median age, 30 years), and inhaled (88%) NPS contained in herbal products (80.5%). Harmful behavior was observed at the scene of acute reaction, including violence (6.9%), traffic accidents (4.9%), and self-injury or suicidal attempts (1.1%). Other than neuropsychiatric and physical symptoms, many patients also had physical complications such as rhabdomyolysis (17.5%), liver injury (12.4%), acute kidney injury (9%), and physical injury (1.9%). Of the 256 patients (43.5%) admitted to hospitals, 35 (5.9%) were hospitalized for seven or more days. Most patients (93.2%) completely recovered, although a few (1.4%) died. However, synthetic cannabinoids and synthetic cathinones were only detected in the blood of five patients. <i>Conclusion</i>: Consumption of NPS-containing products have been associated with harmful behaviors such as violence and traffic accidents, physical complications (e.g., rhabdomyolysis, liver injury), death, or physical and neuropsychiatric symptoms. Compared to a previous survey (2006–2012), the present survey revealed more severe toxicity.