Drug users are giving free samples of P with marijuana teenagers bought. Tinny houses are one of the main methods of cannabis distribution to young people and police have previously voiced concern that other drugs such as methamphetamine, known as P, have been pushed through their established channels. The discovery of gangs selling cannabis laced with P to teenagers has spurred on Auckland police in the war against the cannabis drug trade. 
Stories like these have been cropping up regularly in the New Zealand media since United Future MP Judy Turner issued her Tinny houses offer 'free' P samples media release in 2003. The November NZPA story was widely reported, and led to considerable discussion around the sector (well, around Mythbusters' water cooler, at least). Just how true are such claims?
Since 2003, Social and Health Outcomes Research and Evaluation has been tracking changes in drug use and selling by interviewing key drug scene informants including users, treatment workers and enforcement staff. According to its 2004 report, a number of informants did say that some tinny houses and cannabis dealers were now selling methamphetamine.
The 2005 Illicit Drug Monitoring System survey  asked regular drug users where they bought drugs. Only 2 percent of methamphetamine users reported buying it from a tinny house in the previous six months. Most had bought it from a friend's house, at an "agreed public locations", or in a nightclub.
Many of the claims have come from unnamed police and are difficult to substantiate. Even when assertions can be attributed they appear to represent differing views. Claims about P and tinny houses were made by West Australian Superintendent Fred Gere at the 2003 New Zealand Annual Police Conference in 2003. However, Dave Montgomery, the chair of the New Zealand Police Managers' Guild Trust, has written that, "Overseas suppliers have made links with ethnic and motorcycle gangs in this country who handle the local distribution. These drugs are not likely to be sold at 'tinny houses' but by people who know people, just like cannabis used to be." 
As yet no research has addressed the specific question of free methamphetamine being offered to those purchasing cannabis. However, drug surveys have asked current cannabis buyers whether their dealer had encouraged them to buy other drugs. Around a quarter of users (1.4 percent of the overall sample) said they "knew or thought they knew that their dealer sold other drugs", but only 9 percent of these (0.5 percent overall) said their supplier had encouraged them to buy other drugs.
Wilkins, Reilly and Casswell reviewed whether buyers from tinny houses were more likely than other cannabis users to use multiple drugs. They concluded, "Those buying cannabis from 'tinny' houses did not appear to be subject to any additional persuasion to purchase other drug types than those purchasing cannabis from the personal market. 'Tinny' house cannabis buyers also did not appear to have any higher levels of other drug use than personal market buyers, except in the case of high potency cannabis." 
Claims that gangs are lacing cheap cannabis deals with methamphetamine are widespread among police, and a former user made this claim on TVNZ's One News in 2004. However, as yet Mythbusters has been unable to find any case where a drug seller or someone running a tinny house has been charged or convicted of selling cannabis mixed with methamphetamine, or with giving away samples of methamphetamine. We have also been unable to find any case where samples of laced cannabis have been produced.
Sceptics about these claims, including drug treatment workers, have noted that cannabis and amphetamines have significantly different effects. Cannabis is smoked as a relaxant, while methamphetamine is valued as a hyper-stimulant. In his Hard News blog, Mythbusters' favourite media commentator Russell Brown also pointed out that methamphetamine is not actually smoked like cannabis but is gently heated to release vapours. The result of smoking would be to burn most of the methamphetamine for little or no effect.
Similar stories have circulated for decades, with opium and heroin taking the place of methamphetamine. An analysis of cannabis samples which regular users considered produced unusual effects found no evidence of adulteration.
1. NZPA (2006, November 29). Lower priced P attracting more teens. Printed on Stuff, 29 November 2006.
2. Gower, P (2006, August 5). Porn movie plus tinny for $35. New Zealand Herald. Retrieved from http://subs.nzherald.co.nz/section/1/story.cfm?c_id=1&objectid=10394708
3. New Zealand Herald. (2006 March 02). Cannabis laced with P sparking police raids on tinny houses. Retrieved from http://subs.nzherald.co.nz/topic/story.cfm?c_id=217&ObjectID=10370700
4.Turner: Tinny houses offer 'free' P samples. Press Release: United Future NZ Party Friday, 22 August 2003, 10:55 am. Retrieved from www.scoop.co.nz/stories/PA0308/S00439.htm
5. Wilkins C, Rose E, Trappitt D, Sellman, D., Adamson, S. & . DeZwart, K. (2004). Survey of New Zealand meth scene changes. Recent changes in the methamphetamine scene in New Zealand: Preliminary findings from key informant surveys of drug enforcement officers and drug treatment workers.
6. Wilkins C and Sweetsur P. Research briefing: Key Findings from the 2005 Illicit Drug Monitoring System (IDMS). November 2005. (From report by Dr. Chris Wilkins, Melissa Girling, Paul Sweetsur and Rachael Butler)
7. Plowman, S (2003, November). Organised crime expert delivers simple message: Take the 'P'rofit out of organized crime by seizing ALL gang assets. Police News, 166-169.
8. New Zealand Police Managers' Guild Trust. [website] (not dated).
9. Field and Casswell 1999b, cited in Wilkins C & Casswell, S (2002). The cannabis black market and the case for the legalisation of cannabis in New Zealand. Social Policy Journal of New Zealand, 18. Retrieved from http://www.msd.govt.nz/about-msd-and-our-work/publications-resources/journals-and-magazines/social-policy-journal/spj18/cannabis-black-market18-pages31-43.html
10. Wilkins, C, Reilly J.L. & Casswell, S. (2006). Cannabis 'tinny' houses in New Zealand:Implications for the use and sale of cannabis and other illicit drugs in New Zealand. Addiction, 100, 971-980
11. Plowman, S (2003, August). The timebomb of P. Police News, 106-7.
12. TVNZ One News, June 6, 2004. Claims cannabis laced with P.
13. Russell Brown (2006, March 06). Three Things. Hard News. Retrieved December 21, 2006 from www.publicaddress.net/default,2976.sm#post2976
14. Le Vu S. Aquatias S. Bonnet N. Debrus M. Fournier G. Beauverie P. (2006). Chemical content of street cannabis [French] Presse Medicale. 35(5 Pt 1):755-8, May.
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