A teenager is warning others against the dangers of K2 synthetic cannabis, which she blames for a manic episode in which she battered and bruised her own face.

"I was doing crazy things, and that was just not like me ... I am normally happy and chilled," said Emily Holkenbrink, 18, of Dunedin.

She said she had been smoking the product for the past year and had developed a 6g-a-day habit costing her $17 to $20 a day.

However, her legal high habit has been stubbed out after a manic episode last month which resulted in her being sent to an isolation ward at a psychiatric hospital.


"I was possessed by a demon ... I did not know what was happening. I started screaming so loudly that I did not even recognise my own voice."

Miss Holkenbrink says that incident was the result of her K2 habit, which left her feeling agitated and aggressive, and ending with her punching herself in the face.

She contacted the Otago Daily Times after reading of the growing concern about the product and its effect on youth.

"Everyone I know is doing this. I don't care if all my friends hate me for talking about it, but I want this stuff off the market."

She had spent thousands of dollars on synthetic cannabis, such as Kronic and Tai High, but it was the still-legal K2 that was causing her friends the biggest problems.

"People are having nightmares about killing their friends and family ... this is is horrendous stuff."

She had sold most of her possessions to pay for the drugs, readily available at many city dairies.

Twenty-eight substances have been put under temporary bans, removing more than 50 synthetic cannabis products from the market.

Miss Holkenbrink said that since giving up the drugs she had lost 10kg, her skin was clearing and she was feeling excited about the future.