`I hope our findings can contribute to greater awareness of mental health in prisons and the importance of treatment, ´says Katrine Vellesen Løken, adding:

`At the same time, this raises critical questions about why so many people do not receive help earlier, before crime is committed. ´

Løken is a professor at the Department of Economics and a researcher at the Centre of Excellence FAIR, and one of three authors of the study.

The first study of its kind

Mental Health Consequences of Correctional Sentencing  is the first study to document clear, causal effects of mental health care in prisons on inmates’ lives – both during and after incarceration. The research has now been published in the American Economic Journal: Economic Policy (see facts).

`We have long known that many inmates struggle with mental health problems, but not how treatment affects their lives. Now we clearly see that mental health care in prison makes a real difference, ´ she says.

In October 2025, more than 3,000 people were incarcerated in Norwegian prisons. Many struggles with poor mental health. A study from last year showed that six out of ten inmates in Norway had a mental disorder.

`When mental health problems are so widespread, it is important to understand whether – and under what circumstances – the correctional system improves or worsens mental health, ´ says Løken.

This raises critical questions about why so many people do not receive help earlier.

Katrine V. Løken

Strong positive results

In Norway, inmates are entitled to the same health services as the rest of the population. This means that many receive help – often for the first time – to address their problems.

The researchers believe this system plays an important role.

`Rehabilitation works when we truly invest in it, ´ Løken comments.

Reduced reoffending

The study documents clear results. The researchers identify three key effects of mental health care in prison:

First, former inmates commit fewer crimes after release. Access to mental health treatment during incarceration significantly reduces the risk of reoffending.

Second, they experience better mental health over time. Inmates who received treatment had fewer mental-health-related consultations after release.

A third, and very important, consequence is that former inmates were better equipped to remain in employment after serving their sentence.

We found surprisingly strong effects of the help they received.

Katrine V. Løken

`We found surprisingly strong effects of the help they received. This is why we question why so many people do not receive or accept help before they commit crimes. Based on our research, it is reasonable to argue that earlier intervention could help prevent or reduce criminal behavior, ´ says Løken.

Norwegian data

The study is based on comprehensive Norwegian register data. The researchers linked health records, criminal convictions, and employment information for everyone who served a prison sentence between 2006 and 2014. They were able to follow individuals for up to five years before and after incarceration.

The researchers also distinguished between mental and physical health using diagnostic codes from each health care visit and tracked how often individuals accessed health services.

`Overall, the data gave us a unique opportunity to see how mental health develops for people who receive a sentence now, compared to those who receive the same sentence slightly later. This allows us to estimate the actual impact of incarceration on mental health. ´

This is of course not an argument for using prison as a form of treatment.

Katrine V. Løken

A controversial finding

The study also shows that many inmates experience improved mental health while in prison.

`This is of course not an argument for using prison as a form of treatment. But it illustrates how inadequate health care was for many people before they were sentenced, ´ says Løken.

She believes the results send a strong signal to health authorities about the role mental health care can play in preventing crime.

`What do you hope will happen next with this research? ´

`Greater attention to mental health in prisons. But also, that it inspires a closer look at why treatment failed earlier. What was not working before people committed crimes? Perhaps that can help prevent crime in the first place. ´

Why Salvanes succeeds where almost everyone else is rejected

Over the past 20 years, NHH professor Kjell G. Salvanes has published research in the world’s most prestigious economics journals 24 times. That record has made him the highest-ranked economist in Norway.

Essays on Overconfidence and Development Economics

On Friday 23 January Adrien Dautheville will hold a trial lecture on a prescribed topic and defend his thesis for the PhD degree at NHH.

• Share on Facebook
• Share on Twitter
• Share on LinkedIn
• Share by e-mail