An increase in cases of long-term users of synthetic cannabis experiencing psychiatric effects and suicidal tendencies has prompted a warning from the Dunedin-based National Poisons Centre.
''We are seeing a trend and we are just wanting to alert people,'' toxicologist Leo Schep told the Otago Daily Times yesterday.
That alert comes after a spike in calls to the centre from long-term users of the widely available products.
Neuropsychiatric effects associated with long-term use include anxiety, tremors, aggression, hallucinations, psychosis and anger.
Another recent trend was for patients to experience ongoing paranoia linked with suicidal thoughts.
Dr Schep said peer-reviewed papers and reports to the centres also suggested the effects of chronic use was more intense and prolonged than any one-off exposure.
Paranoia and hallucinations may be triggered following exposure to some products, but not all users were experiencing adverse effects.
''It won't affect all people, nor act as a trigger for those smoking it. But it definitely does in some people.''
The centre received nearly 150 calls concerning synthetic cannabis products of which 30, and the most recent, were concerning chronic use.
''These people who smoke synthetic cannabinoid products are thinking they are touching things, they are hearing things and they are seeing things.''
Dr Schep said evidence also suggested the synthetic product appeared to be addictive, and he had a simple message for those smoking the product.
''Stop taking it.
''There comes a day, like all the drugs of addiction, where you have to move on.''
Sergeant Chris McLellan, of Dunedin, said police were dealing almost with daily cases of long-term users who were ''agitated and having psychotic episodes''.
Associate Health Minister Peter Dunne told the ODT it was a ''matter of real concern that any products would have that impact on those who use them''.
''While I am overseas at the moment, I will be seeking further information from health officials on this issue.
''This is exactly why the pending psychoactive substances legislation is so important, and I expect to be introducing that very soon so that it can take effect from August when the temporary notices begin to expire,'' Mr Dunne said.
