ADHD symptoms can be confused with anxiety or depression, leading to delayed diagnosis. Photo / 123rf
ADHD symptoms can be confused with anxiety or depression, leading to delayed diagnosis. Photo / 123rf
ADHD patients more likely to have a substance abuse disorder, New Zealand Drug Foundation report confirms
Young people who get diagnosed and treated for ADHD far less likely to develop drug problems later in life
Failures in diagnosing and treating ADHD in New Zealand could be contributing to significant drug harm.
Untreated ADHD in New Zealand is likely to be contributing to significant drug harm, according to a new report which highlights the clear link between the condition and substance abuse.
The New Zealand Drug Foundation report said people with Attention Deficit Hyperactivity Disorder (ADHD) were much more likely to use legal and illegal drugs and develop an addiction – citing one study which showed up to half of adults with the neurological condition would meet the criteria for substance use disorder in their lifetime.
The report, Neurodivergence and Substance Use, was published today and is based on a review of overseas studies and interviews with patients in New Zealand.
Drug Foundation executive director Sarah Helm said the evidence linking ADHD and substance harm was stark. An Australian study of people who regularly used illicit stimulants found that 45% screened positive for adult ADHD. Research in the United States found that one in five people with a substance abuse disorder had ADHD.
“This suggests that a different approach to ADHD diagnosis and support could make a significant contribution to reducing addiction and substance harm,” Helm said.
One study found that young people with ADHD who received appropriate and timely medication had an 85% reduction in risk for developing a drug abuse problem compared with those who did not receive treatment.
However, ADHD diagnosis rates in New Zealand are low and the waiting list for assessment is long. A New Zealand study published in May said around 2.6% of the population could have ADHD, but just 0.6% were getting medication for the condition – indicating a significant treatment gap.
There was also stigma in New Zealand around giving stimulant medication to patients with a record of drug use, because of concerns they were more likely to abuse or “divert” it.
Overseas evidence told a different story, showing that stimulant medication did not act as a “gateway” to illicit drugs or abuse. Waiting until a person’s drug problem was resolved before treating ADHD was not best practice and could hinder their recovery. Where there were concerns that a person with both ADHD and a drug problem might abuse or divert medication, they could be offered alternative treatments such as long-acting stimulants, which did not carry the same risks.
There was no single reason for the links between ADHD and drug use. ADHD patients might use illicit drugs for self-medication or because of impulsivity or behavioural disinhibition. Undiagnosed patients also might be more likely to use methamphetamine or cocaine because they had a similar effect to some ADHD medications.
ADHD New Zealand spokesman Darrin Bull said the report highlighted how barriers to ADHD treatment could seriously affect people’s lives.
“Untreated ADHD can impact people’s relationships, their employment, and their mental health,” he said. “Add in a heightened risk of drug harm to that mix and you can see why we need to get serious about making support and treatment more accessible.”
The Drug Foundation report made a series of recommendations, including streamlined access to ADHD screening for individuals with substance abuse disorders, improved access to ADHD diagnosis, and funded access to long-acting stimulants.
Drug Foundation NZ executive director Sarah Helm. 29 August 2024. Photo supplied
RNZCGP medical director and Tauranga GP Dr Luke Bradford said ADHD diagnosis rates in NZ were low, especially among adults, women, and Māori and Pacific populations. Photo / Mead Norton
Royal College of New Zealand General Practitioners (RNZCGP) medical director Dr Luke Bradford said some of these initiatives were under way. The RNZCGP was working with the Ministry of Health to change regulations to allow GPs to diagnose ADHD and prescribe medication. The college had hoped for this to happen by the end of the year, but it was now more likely to be mid-2025.
Pharmac plans to fund lisdexamfetamine (brand name Vyvanse), a slow-release stimulant, from December for ADHD patients. It is also reviewing the Special Authority rule which requires ADHD patients to get approval every two years to continue using stimulant medications – a move which could free up specialists to carry out more ADHD assessments.
The report said there was a limited understanding of the relationship between autism spectrum disorders and substance use, but that some patients might be at increased risk of harmful drug use or engage in problematic drinking.
Isaac Davison is an Auckland-based reporter who covers health issues. He joined the Herald in 2008 and has previously covered the environment, politics and social issues.
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