Young people who have offended are more likely than people who have not offended to have mental health problems and they are also more likely to offend again. It may, therefore, be important to identify the mental health difficulties in this group and give them help for these problems.

There are, however, a number of unanswered questions about identifying mental health problems in young people who offend. These include:

• How accurate are the different ways of identifying these difficulties?
• If a difficulty is identified, how well does any treatment given for this difficulty work?
• Does identifying mental health problems in this way represent good value for money?

We sought to identify all research that could help to answer these questions. We identified a small number of studies that looked at how accurate different tools were at identifying mental health problems in this group. Most tools had limited accuracy. We also identified a small number of studies that had looked at whether or not treatments work for mental health difficulties in young people who offend. Although there was some encouraging evidence, it remains uncertain if treatments are effective in this group. In general, our search identified few studies and those studies we did identify were often of low quality.

There is a need for future studies that establish how effective and cost-effective treatments are for these difficulties. There is also a need for future studies that better establish how accurate screening instruments are for identifying mental health problems.