Young detainees often have poor mental health. The earlier they’re incarcerated, the worse it gets

Populist rhetoric targeting young offenders often leads to kneejerk punitive responses, such as stricter bail laws and lowering the age of criminal responsibility. This, in turn, has led to more young people being held in detention.

In Australia, the number of young people held in detention facilities increased by 8% (from 784 to 845) between the June quarter of 2023 and the June quarter of 2024.

But what if some of these young people were treated and helped, rather than incarcerated? A series of recently published studies examining mental health in the youth justice population suggests treatment would be more beneficial than punitive measures – some of which may even promote persistent offending.

Increased incarceration

New South Wales saw a 31% increase in young people in detention between 2023 and 2024.

Increases in youth detention numbers have also been reported in Queensland, the Australian Capital Territory, Tasmania and South Australia over the same period.

About 60% of young people in detention are First Nations youth.

Custody as a catalyst

Young people in the justice system have significantly higher rates of mental ill-health and adverse childhood experiences than their peers in the general population.

However, less clear is how involvement in the justice system, particularly custody, affects the severity and trajectory of these mental health issues over time.

Our team examined how exposure to the justice system affected mental health among young people in NSW. We analysed administrative health and justice data over two years post-supervision.

These data came from more than 1,500 justice-involved youth who participated in the Young People in Custody Health Survey in 2003, 2009 and 2015 and Young People on Community Orders Health Survey between 2003 and 2006.

We found young people who had spent time in custody faced markedly higher rates of subsequent psychiatric hospitalisation compared with those supervised in the community.

The risk of psychiatric hospitalisations was higher for those with multiple custody episodes. This demonstrates the significant negative impact of incarceration on the mental health of young people long after they are released.

We also examined how the impact of custody on psychiatric hospitalisations differed by age.

We found psychiatric hospitalisation rates were similar among youth aged 14–17 years who had been supervised in the community, compared with those aged 18 and older.

However, youth aged 14–17 who were placed in custody were hospitalised at significantly higher rates than their older peers aged 18 and above.

This suggests incarceration is particularly harmful for younger offenders.

How does this affect crime?

When we examined the long-term consequences of youth detention on subsequent offending, we found conviction during adolescence, especially before the age of 14, significantly increased the likelihood of later entering the adult prison system.

Those who were incarcerated during adolescence faced a fivefold increase in the risk of being incarcerated as an adult, compared with young people who’d never been in custody.

This suggests it may be beneficial to delay the involvement of young people in the justice system to help prevent repeat offending in the future.

Breaking the cycle

So what can be done to help?

In NSW, laws allow young people with mental health conditions to be diverted from judicial processes into treatment. Such laws for young people also exist in other states, although specific models vary.

While research shows those diverted into treatment have a lower risk of reoffending, less than half of eligible youth receive this option.

How do we help those who miss out? Our studies examined whether going to mental health services voluntarily (without a court order) could help reduce recidivism.

Among boys who had been in custody, we found they were 40% less likely to reoffend if they received mental health treatment after release than those who did not receive such treatment.

A similar, but larger, benefit was observed among boys supervised in the community. There, mental health treatment was associated with a 57% reduction in reoffending risk.

Evidence-based reform

Evidence shows punitive measures do not deter youth crime, but instead are likely to perpetuate cycles of offending into adulthood.

Policymakers should reimagine youth justice to protect young people and create real pathways to rehabilitation.

Raising the minimum age of criminal responsibility to delay the onset of formal contact with the justice system aligns with developmental science and prevents early criminalisation of young people.

Read more: Locking up young people might make you feel safer but it doesn't work, now or in the long term

Enhancing routine mental health screening in the justice system and expanding access to diversion programs is warranted.

Our findings on the benefits of routine mental health treatment highlight the potential for more integrated approaches. When combined with wraparound services for health and education, they could be even more effective.

As detaining a young person costs around $1 million annually, mental health treatment-based approaches make sound financial sense too.