PRISONERS who have suffered head injuries may not be the most immediately sympathetic cause. When involvement in violent lifestyles, perhaps featuring gangs or drugs could lie behind cases, there will be those who will feel limited concern.

But there is an element of the chicken and the egg here. Evidence suggests that those who have suffered brain trauma are more likely to be involved in the criminal justice system. They may be more impulsive, less able to control their aggression or have lower levels of concentration and ability to overcome problems in their own lives.

While criminality may have preceded such injury for some, others may have seen their lives go awry following a violent incident.

We know people who grew up in the care system are more likely to end up in jail – it is reasonable to think that a violent or neglectful upbringing may have contributed to their problems. Women who have been victims of domestic violence are another example.

Regardless, the principle of equal access to health care should not be denied to someone as part of a prison sentence. Yet it often is, according to the British Psychological Society.

In evidence to Holyrood’s health committee, the society says communication between health and social care agencies and prisons is inefficient or absent. Prison staff are often unaware of the consequences of untreated brain injuries.

Much better screening and more effective access to treatment is the decent thing to do when prisoners are three to four times more likely to have suffered traumatic brain injuries. But there is also a wider public interest in addressing the long-term problems such injuries can cause, and the need to rehabilitate such prisoners.

Their cost to criminal justice services can add up to hundreds of thousands of pounds over a lifetime.

This is not about providing excuses – it is right that people are punished for the offences they have committed. But the prison sentence is the punishment. Inadequate access to healthcare should not be part of that too.