Neuroscientist warns against the uncritical use of opioids

“The risks associated with opioid use are high, with overdose death as the worst-case scenario,” says Siri Leknes.

Most patients who undergo surgery in Norway are given opiates. This photo shows the emergency room at Telemark Hospital after a traffic accident.

(Photo: NTB / Scanpix)

Gro Lien Garbo COMMUNICATIONS ADVISER

Presented by: University of Oslo

Published 22 April 2025 - 00:01

Most patients who undergo surgery in Norway are given opiates.

That means that even if only one per cent develop a problem, 50,000 people could be affected in a population of five million.

Siri Leknes is a professor of social and affective neuroscience at the University of Oslo's Department of Psychology. She has delved deeply into the medical use of opioids and how they affect us – both positively and negatively.

What began as basic research has evolved into public health work, especially in light of the US opioid epidemic.

Leknes notes that over the past 200 years, we have created many medications that act on the same neurotransmitters in the brain – heroin, morphine, and oxycodone, to name a few. Heroin was first launched as a cough syrup.

“Many opioids have been launched as a ‘non-addictive’ medication. But this has been incorrect every time. So far, we have failed to identify any opioid painkillers that do not lead to addiction,” she says.

1 in 20 Americans affected

The neuroscientist points to statistics from the US showing that 1 in 20 adult Americans now meet the criteria for opioid use disorder.

Neuroscientist Siri Leknes and her team have researched opioids, pain, stress, and reward for over 15 years. She warns against the uncritical use of opioids.

“This is a problem that could have largely been avoided had the healthcare system been less liberal with prescribing opioids,” says Leknes.

Norwegian and European guidelines have generally been more restrictive, she adds, but opioid addiction is still a growing concern here too.

“Everyone who undergoes surgery at some point in their life in Norway and the western world – and that’s almost all of us – is given opioids," she says,

Leknes explains that if only one per cent of us develop a problem, in a population of five million, that means 50,000 could develop problematic opioid use.

Who is most at risk?

Leknes emphasises that addiction does not just harm the individual, it affects work life, and especially family life.

A key question is in which situations, and for which patients, can opioids be safely prescribed?

“We don’t have a clear answer to that, but we know that genetics play a role. This means, for instance, that some families may be more predisposed to addiction than others,” says Leknes.

She also points to research suggesting that childhood trauma may increase the risk of addiction.

Leknes and her research team have found that some patients report enjoying the opioids they receive before surgery.

“Most will think they need to be careful, even if it feels good, because opioids are considered dangerous. Others will not have those reservations. This could be a risk factor too,” she says.

A major issue in the US is that patients are often sent home with large amounts of opioid pills after surgery. There are so many spare opioids in people’s homes that real estate agents have noticed some individuals attending open houses just to access these unused medications.

Ibuprofen and paracetamol often work just as well

Leknes refers to studies showing that ibuprofen and paracetamol can often work just as well as opioids for pain relief – even for severe pain after surgery or accidents.

“For most people – including many physicians – this is surprising. Opioids are referred to as strong painkillers, and many think that strong pain necessitates precisely that. However, a significant reason we call them strong painkillers is due to their dangerous side effects,” she says.

Leknes understands that healthcare personnel face a complex web of issues every day, and that reaching for opioids can become routine – or something patients expect.

“It’s easier for me, who has researched opioids for years, to see the paradox of using opioids when ibuprofen and paracetamol often serve the same purpose,” she says.

Still, Leknes stresses that opioids have their place.

“The advantage of opioids is that there's no ceiling effect. If you take two 500 mg paracetamol, taking another will not help until the original effects have worn off. There's no greater effect with a higher dose. With the so-called strong opioids, however, there's no such limit," she says.

Leknes explains that opioids remain an essential part of medical treatment, especially in cases where pain does not respond to medications like ibuprofen or paracetamol.