Patterns of new psychoactive substance use among opioid-dependent patients attending for opioid agonist treatment

Background: Until 2010, New Psychoactive Substances (NPS) could be bought legally in headshops in Ireland. Research on NPS use is lacking among opioid-dependent patients, a group likely to be at increased risk of NPS consumption. Aim: Among patients attending an opioid agonist clinic we sought to investigate reasons for NPS use, administration, adverse effects, and consumption in the previous three months. Methods: The study was carried out in the National Drug Treatment Centre, Dublin, Ireland. Data were collected on 213 participants through an interviewer-administrated survey. Results: Most participants were male (n=150, 70.4%). A total of 131 (61.3%) participants had used NPS at least once, while 14 (6.6%) had used NPS in the last three months. Being older at the time of interview, and when first consuming illicit substances were inversely associated with NPS consumption. Ninety-three participants (71.5%) bought NPS for the first time from a headshop, 28 (21.5%) from a friend, and nine (6.9%) from a dealer. After the closure of headshops, dealers were the most common source of NPS. Cathinones were the most commonly consumed NPS class. One third of participants injected NPS. Almost half the participants experienced no adverse effects although paranoia did occur frequently, with 34 (26.2%) participants reporting paranoia. Conclusions: In the current study the majority of those who had ever consumed NPS did so before 2010 (when legislation forced the closure of headshops), and only 9 (7.1%) participants reported NPS use after 2010, suggesting that making the supply of NPS illegal reduced NPS consumption. Furthermore, since a high proportion of participants administered NPS intravenously, the closure of headshops is likely to have lead to improved health outcomes among this group of patients.