A tenth of synthetic cannabis users surveyed in Northern Ireland have also taken heroin, a study showed.

Serious side-effects were reported by those who had used new psychoactive drugs, including significant mental health problems and heart, liver, stomach and bladder issues, Queen’s University Belfast research showed.

Alcohol and other stimulants like MDMA were also taken alongside the outlawed substances.

They were formerly known as legal highs but were banned in May 2016.

They include drugs such as synthetic cannabinoids – sometimes referred to as “spice” – and mephedrone – also known as “meow meow”.

Co-investigator, Dr Nina O’Neill, research fellow from the School of Nursing and Midwifery at Queen’s, said: “We were also able to look beyond the reported physiological effects of the drugs and learn more about the wider impact of new psychoactive substance (NPS) use on the individual, including their physical, psychological and social wellbeing.”

“Our findings help to clearly explain why people use NPS in the ways that they do.”

Co-investigator, Dr Anne Campbell, senior lecturer from the School of Social Sciences, Education and Social Work, and the Centre for Evidence and Social Innovation at Queen’s, added: “We hope that this will help experts on NPS to consider interventions which would be most helpful in preventing people from using NPS in the future and reducing harms for people who already use NPS in the interests of better health across society as a whole.”