The committee’s inquiry looked at how substances enter Scotland’s prison estate, the impact of substances in prisons, and rehabilitation and support services.

The committee found that substance misuse in custody remains a systemic challenge across the prison estate, and reflects deep-rooted societal issues such as poverty, trauma, inequality and mental ill-health. It says systemic reform which treats substance misuse in Scotland’s prisons as a public health issue, not a justice one, is essential to tackle it effectively.

Evidence is highlighted by the committee of prison healthcare teams often operating under pressures that would be deemed unacceptable in community settings, including chronic understaffing, limited clinical space, high levels of acuity, and inadequate digital infrastructure. The committee say persistent and extreme overcrowding in prisons also acts as a major barrier to preventing substance misuse issues and providing effective care.

Highlighting the variations in healthcare provision between NHS Boards and wider health system failings, the committee say that without significant improvement to the capacity, governance and integration of health and social care services for people in custody, prisons will struggle to absorb unmet clinical needs.

On supply and security, the committee found that total prohibition is unrealistic in an era of synthetic cannabinoids and nitazenes, and that organised-crime networks continue to exploit vulnerabilities in the prison environment. Although improved technology and the use of window grilles can limit supply, the committee say success must be measured by reductions in harm and demand, not simply by the number of seizures.

Mental-health care is an area of particular concern to the committee and the report highlights evidence of inconsistent access across the prison estate. The committee is calling for parity between custody and community services to reduce harm and improve post-release outcomes.

Criminal Justice Committee convener, Audrey Nicoll MSP, said: “The evidence we have gathered reveals a prison system and staff under extreme pressure, with issues such as under-resourced services and overcrowding exacerbating the myriad impacts of substance misuse in prisons. The goal is clear: to break the cycle of addiction and reoffending, and to protect lives.

“It’s clear more must be done to reduce pressure on the workforce and reduce overcrowding, and ensure adequate resourcing of services, particularly specialist staff – all of which are vital to tackle substance misuse in prisons.

“But these issues cannot be understood in isolation from the broader social determinants of health and justice. Systemic reform which prioritises recovery, rehabilitation, and reintegration is essential in order to begin to tackle the complex and intertwined issues related to substance misuse.

“Our committee is determined that this inquiry is not the endpoint of scrutiny, but the foundation for continuing parliamentary oversight of progress in reducing drug and alcohol harms in custody and improving outcomes for individuals.”