Individual dollar expenditure and earnings from cannabis in the New Zealand population.

INTRODUCTION: : High spending on illegal drug use can potentially provide insight into a range of drug related harm such as poor health, financial hardship, loss of opportunity, family neglect and income generating crime. Assessing the impact of high spending on drug use is complicated by the fact that many heavy drug users support their high expenditure on drug use through selling drugs. The aim of this paper is to estimate individual dollar expenditure and dollar earnings from cannabis in New Zealand.

METHODS: : As part of the 2003 New Zealand national household drug survey, detailed data were collected on cannabis use and purchasing in the previous 12 months. Those who had purchased cannabis in the previous year were divided into two groups for further analysis: 'cannabis buyers' (i.e. those who only purchased sufficient cannabis for their own personal consumption needs); and 'cannabis dealers' (i.e. those who purchased large surpluses of cannabis for re-sale on to others).

RESULTS: : Seventy-two percent of those who had purchased cannabis in the previous year were 'cannabis buyers' only. Cannabis buyers spent a mean of $817 (NZD) each on cannabis in the previous year (median $120). Cannabis dealers spent a mean of $5988 each on cannabis in the preceding year (median $1250). Once we accounted for projected earnings from selling surplus cannabis, half of the cannabis dealers achieved a mean net annual financial gain of $2739, and the remaining half were left with a mean net annual financial loss of only $350 over a year. Overall, 81% of all those who had purchased cannabis in the previous year had spent less than 5% of their gross annual personal income on cannabis, with 14% of these making a net financial gain. The proportion of income spent on cannabis was highest among those in the two lowest income earning groups, where approximately 8% spent 20% or more of their income on cannabis. Both cannabis buyers and cannabis dealers spending 10% or more of their income on cannabis were four times more likely to be unemployed than the wider population.

CONCLUSIONS: : For the vast majority of those who had purchased cannabis in the previous year, spending on cannabis had only a small impact on their total annual income levels. High spending on cannabis can potentially be substantially offset by earnings from selling surplus cannabis. High spending on cannabis had its greatest impact among low income earning groups where approximately one in 13 low income cannabis spenders were spending high proportions of their income on cannabis. There appeared to be some relationship between high cannabis spending and unemployment and this warrants further investigation.