Different countries exhibit varying attitudes towards rehabilitation within their custodial sentencing systems, often reflecting broader societal values and historical contexts. For example, Nordic countries like Norway and Sweden emphasise rehabilitation and reintegration, investing heavily in educational and vocational programmes within prisons. Their prisons are designed to mimic normal life as much as possible, encouraging personal responsibility and preparation for reintegration. This approach is underpinned by the belief in the potential for change within every individual and the societal benefit of reducing reoffending. In contrast, countries with a more punitive approach, such as the United States, have historically placed a greater emphasis on deterrence and incapacitation. High incarceration rates and a focus on long-term sentences reflect a belief in punishment and public safety through containment. However, there is a growing recognition of the importance of rehabilitation even in more punitive systems, driven by the high costs of incarceration and the desire to reduce recidivism rates. The effectiveness of rehabilitation over punitive measures in reducing reoffending is increasingly acknowledged, leading to prison reform efforts worldwide.

The rehabilitation aim of custodial sentencing is underpinned by several psychological theories that seek to explain and address criminal behaviour. Cognitive-behavioural therapy (CBT) plays a significant role, based on the idea that changing maladaptive thought patterns can alter behaviour. CBT in prisons focuses on helping offenders understand and change the thinking that led to their criminal behaviour, promoting personal responsibility and social skills. Another influential theory is the social learning theory, which suggests that behaviour is learned through observation and imitation. Rehabilitation programmes based on this theory might focus on developing pro-social behaviours through positive role models and reinforcing non-criminal behaviour. Humanistic psychology also contributes, emphasising the importance of treating individuals with respect and dignity and supporting their self-actualisation. Programmes inspired by this approach may focus on enhancing self-esteem and empathy, aiming to foster a sense of personal value and social connection that discourages future offending.

Mental health interventions in custodial settings are crucial for rehabilitation, as they address the psychological issues that may underlie or contribute to criminal behaviour. Such interventions can range from individual therapy and group counselling to more structured psychiatric and psychological treatments for specific disorders. Addressing mental health issues can significantly impact an offender's ability to engage with other rehabilitative efforts, such as educational and vocational training. By improving an individual's mental health, interventions can reduce the risk of recidivism, enhance the quality of life, and increase the chances of successful reintegration into society. Effective mental health support also helps to manage stress, improve emotional regulation, and develop coping strategies, which are essential skills for dealing with the challenges of re-entry into the community. Ultimately, mental health interventions are a critical component of a holistic approach to rehabilitation, acknowledging the complex interplay between psychological well-being and criminal behaviour.

Risk assessment tools are instrumental in determining the aims of custodial sentencing, particularly in tailoring interventions to reduce recidivism. These tools evaluate the likelihood of reoffending and identify the criminogenic needs of individuals, which are factors that contribute to criminal behaviour. By assessing risk and needs, corrections officials can make informed decisions about the level of security required, the length of the sentence, and the types of rehabilitation programmes that would be most beneficial for each offender. High-risk individuals may receive more intensive intervention and monitoring, while low-risk offenders might benefit from less intrusive measures, focusing on support and reintegration. Risk assessment tools thus ensure that resources are allocated efficiently, prioritising interventions that are most likely to reduce reoffending and protect public safety. Moreover, these tools help in achieving a balance between the punitive aspects of sentencing and the rehabilitative goals, aiming for outcomes that are beneficial for both the individual and society.

Restorative justice complements the aims of custodial sentencing by focusing on the repair of harm caused by criminal behaviour, rather than on punishment alone. It seeks to involve all stakeholders, including victims, offenders, and the community, in the resolution process, encouraging offenders to take responsibility for their actions and to understand the impact of their behaviour. This approach can enhance the rehabilitative aspect of custodial sentencing by promoting empathy and understanding, encouraging personal growth and transformation. Restorative justice programmes, such as victim-offender mediation and community service, can be incorporated into custodial sentences as a way to address the needs of the victims and the community, while also contributing to the offender's rehabilitation. By fostering a sense of accountability and providing an opportunity for restitution, restorative justice can help to reduce recidivism, improve victim satisfaction, and strengthen community ties, aligning with the broader goals of reducing crime and facilitating successful reintegration.