Women are much more likely to become addicted to prescription painkillers prescribed by doctors than men, a new study suggests, and researchers say that underscores the need for different treatment options based on gender.

Of the of 503 patients attending Ontario methadone clinics surveyed in the McMaster University study, 52 per cent of women reported doctor-prescribed painkillers as their first contact with opioid drugs, compared to 38 per cent for men.

They study, which was published in Biology of Sex Differences Monday, also found other gender differences. Compared to men, women in treatment had more physical and psychological health problems, more childcare responsibilities, and were more likely to have a family history of psychiatric illness.

"We definitely found an overrepresentation of women," said senior author Dr. Zena Samaan. But, she added, it's not totally clear why women are disproportionately affected by opioid dependence originating from prescriptions.

"Partially, I think it's the availability of opioid prescriptions," she said. "And sociological theories also say women are more likely to seek help from a doctor than men."

'Things will only improve if you provide people with better services and tools. You can't simply just give them methadone.'
- Dr. Zena Samaan

Researchers say the study highlights how the profile of opioid addiction has changed. Studies from the 1990s showed an older average age for patients, and higher incidences of intravenous drug use like heroin, largely in men.

But since then, intravenous drug use among methadone patients has reduced by 60 per cent, the study says, coupled with a 50 per cent reduction in rates of HIV in opioid users.

But while those numbers drop, there has been a 30 per cent increase in patients who are becoming addicted to opioids through prescribed painkillers, usually for chronic pain.

The report also cites World Health Organization numbers that say that says Canada consumes more opioid painkillers per capita than any other country.  

Alarm has risen about prescription opioid addiction in recent years. Overdose deaths due to medical and non-medical drug use are now the third leading cause of accidental death in Ontario, the WHO says, and a significant proportion of these deaths have been attributed to opioids.

To combat that surge, a comprehensive follow-up system around prescriptions needs to be instituted, Samaan says — and doctors need to be mindful of the differences between prescribing for women or men.

"To prescribe opioids is very easy – but we don't have the proper resources to follow up," she said. "We don't have the safeguards."

"Things will only improve if you provide people with better services and tools. You can't simply just give them methadone."