Meth is one of the most harmful drugs in the Substance Outcome Harm Index. Photo \/ NZME<\/p>\n
Of particular interest are the various components of harm in the data that could have practical applications for reducing the negative impacts of particular substances across drug policy, treatment for problem users and harm-prevention strategies.<\/p>\n
\u201cIt\u2019s not just whether this drug is harmful. We want to know how it\u2019s harmful,\u201d he said.<\/p>\n
\u201cThe people using meth with really serious problems: who are they and why are they [having serious problems]? We want to look at breaking it down by not only drug type, but also frequency of use, amount used and also the people having the problems. <\/p>\n
\u201cIs it mental illness? Neurodivergence? It\u2019s then about trying to help them with those issues. This could be a really important insight in terms of allocating health services.\u201d<\/p>\n
The data is summarised in the Substance Outcome Harm Index, which has heroin\/morphine (9\/10) at the top, followed by methamphetamine (8.21), and GHB\/GBL (8), also known as fantasy. <\/p>\n
These were significantly higher in cumulative harm than the rest and roughly twice as harmful as alcohol (4.2), which was ahead of cannabis, tobacco, nitrous oxide (nangs) and vaping. The least harmful was LSD, followed by cocaine and then MDMA (ecstasy).<\/p>\n
An important caveat is the methodology is still being developed, with the data and findings \u2013 shared exclusively with the Herald \u2013 in only a preliminary stage.<\/p>\n
It\u2019s also a measure of acute harm rather than something that might emerge years or even decades later.<\/p>\n
\u201cSo with tobacco, \u2018I smoke now and I get cancer 20 years from now\u2019. This index is not going to pick that up very well,\u201d Wilkins said.<\/p>\n
Almost one in five users (19%) reported a mental health problem related to their substance use. This was the most commonly cited issue, ahead of money problems (18.2%), physical health impacts (14.6%) and relationship difficulties (14.3%).<\/p>\n
Unsafe driving (6.7%) and personal safety concerns (6.7%) were comparatively rarely experienced, as was having legal issues (3.1%) linked to substance use.<\/p>\n
Of those who reported a negative experience, most said it was due to a single substance, while a quarter said it was two substances, and one in 10 said it was three. To avoid confusion over which drugs might be responsible for which type of harm, the data from those who ticked more than one substance was excluded from the index.<\/p>\n
Professor Chris Wilkins says the findings \u201cwill be surprising to some\u201d because of the public\u2019s negative connotations attached to drug use in general. Photo \/ Massey University<\/p>\n
The results show \u2013 and advocates for drug law reform have repeatedly said<\/a> \u2013 the Misuse of Drugs Act does not align well with the level of harm associated with particular substances. <\/p>\n LSD and cocaine, for example, are Class A substances, meaning their misuse can lead to the highest penalties, even though they are at the lower end of the harm scale. <\/p>\n Alcohol and tobacco are legal, while MDMA and opium \u2013 each with significantly different harm profiles \u2013 are both Class B substances. <\/p>\n Wilkins\u2019 latest research follows two major reports into drug law reform: one by the Drug Foundation<\/a>, which recommended decriminalising personal drug use while boosting resources for harm reduction, based largely on what has happened in Portugal; and the other by the Helen Clark Foundation<\/a>, which, contrary to popular political opinion, found majority support for shifting from a punitive law to a health-focused one.<\/p>\n The Government has already ruled this out, saying it would be counter to its stated goal of toughening law and order. <\/p>\n Perception v reality<\/p>\n A key attribute of the Substance Outcome Harm Index is that it\u2019s about individual risk rather than total societal harm.<\/p>\n The latter would factor in prevalence of use, which was a major contributor to alcohol topping a New Zealand-specific drug harm index in a 2023 study<\/a>; \u201charm to others\u201d formed a bigger share of overall alcohol harm in the study than \u201cindividual harm\u201d. <\/p>\n The stark difference in prevalence across substances is evidenced in the Health Ministry\u2019s annual health survey: 3.25 million adults (15 and older) had consumed alcohol<\/a> in the previous year, almost five times as many as those who had smoked cannabis, more than 15 times as many as those who had used MDMA, and almost 100 times as many as those who had used opioids.<\/p>\n For his survey, Wilkins said the respondents were broadly representative of the demographics of the population, but with one key difference: they all said they had used drugs in the previous six months.<\/p>\n The survey asked about 12 dimensions of harm: mental health, physical health, relationships, money, driving, personal safety, violence, legal, property crime to pay for drug use, drug dealing to pay for drug use, parenting and work\/study.<\/p>\n Respondents were then asked whether they experienced any of these \u201crelated to your alcohol and drug use in the past six months\u201d, and if so, how severe: from one (mild) to four (very serious).<\/p>\n The results are a snapshot of the period from December 2024 to May 2025.<\/p>\n Wilkins said his team was applying for more funding so they could dive more deeply into the data.<\/p>\n He cannot yet say, for example, what proportion of methamphetamine users reported no harm from their use in the previous six months.<\/p>\n Preliminary findings may surprise those who associate the drug with \u201cviolence\u201d. This scored very low on its harm profile compared with \u201cmoney\u201d or \u201crelationship\u201d problems.<\/p>\n \u201cThis is not saying that methamphetamine use does not contribute to violence, but that most users, on average, do not often experience these issues at a high level of seriousness,\u201d Wilkins said.<\/p>\n He said the stigma of violence might make it less likely to be self-reported.<\/p>\n Driving problems also rated low, and Wilkins noted reports the drug is sometimes used to help tired drivers stay alert.<\/p>\n In contrast, the data aligns with the perception of meth addicts being \u201cforced to sell drugs to pay for drug use\u201d, which had a high harm rating.<\/p>\n \u201cIt\u2019s very early days, but there are some of the really important insights that are surprising,\u201d Wilkins said.<\/p>\n \u201cYou have this idea with heroin, for example, that it\u2019s just about dependency, but there are lots of others: relationship problems, mental health, money problems. It\u2019s a broad cross-section.<\/p>\n \u201cWith nitrous oxide [nangs], the popular impression is that it\u2019s kind of harmless. But if you dig a little deeper, that\u2019s actually not correct. The use of it in a very repetitive way can be responsible for some serious brain injuries.\u201d<\/p>\n It\u2019s also a substance that has lately become available in such high concentrations that the Government announced a crackdown<\/a>.<\/p>\n The addictiveness of some substances \u2013 opioids, methamphetamine, tobacco \u2013 is probably a contributing factor to their high scores when it comes to \u201cmoney\u201d problems. For the latter, increasingly higher prices \u2013 due to excise tax on tobacco \u2013 are also often cited as a leading reason for wanting to quit.<\/p>\n A higher likelihood of drug dependency could also be a factor in GHB\/GBL (fantasy), methamphetamine and opioids scoring highest for \u201crelationship\u201d problems, while MDMA \u2013 sometimes used by couples to enhance their relationships<\/a> \u2013 scored the lowest.<\/p>\n Wilkins\u2019 team is now developing a method for measuring harm components and their respective severity levels. Some people may consider harms related to parenting more serious than those related to property crime, for example, or poor work performance.<\/p>\n No perfect data<\/p>\n This work seeks to iron out inherent issues with self-reported data: how can people\u2019s subjective judgments of harm severity be accounted for? Another issue is how reliable the data is, as opposed to a clinician making more objective observations about harm.<\/p>\n Some of this can be mitigated with the large sample size (4838 respondents), but questions remain on the cocaine data due to its relatively low availability, and hence low frequency of use (and low problematic use). This is despite cocaine consumption skyrocketing in 2024<\/a>, along with methamphetamine, which has triggered a multi-pronged government response<\/a>. <\/p>\n Wilkins believed people assumed, incorrectly, that those who used drugs were unreliable.<\/p>\n \u201cWe generally find that most of the people who take the effort to do the survey, they do it in a pretty honest way. There\u2019s no real reason for them to lie about harm.\u201d<\/p>\n NZ Drug Foundation executive director Sarah Helm acknowledged the research\u2019s limitations – the lack of insight into chronic harm, for example – but said it was nevertheless important.<\/p>\n \u201cIn part, it helps to address the silencing impact of both the criminalisation and stigma surrounding drug use by surfacing people\u2019s real experiences,\u201d she said.<\/p>\n