Headmatters: Aspects of neurocognitive and behavioural impairments related to acquired brain injury in forensic populations.

Acquired Brain Injury (ABI) refers to brain damage occurring after birth and includes both traumatic brain injury (TBI), caused by external forces, and non-traumatic brain injury (nTBI), caused by internal factors such as stroke or hypoxia. ABI is significantly more prevalent in forensic populations (around 40–60%) than in the general population (8–12%). This is clinically important because ABI is associated with neurocognitive impairments, behavioural dysregulation (e.g. impulsivity and aggression), mental health problems, and an increased likelihood of criminal behaviour and recidivism. Risk factors for ABI include age (young children, adolescents, and older adults), sex differences (men are more prone to TBI, women to stroke), low socioeconomic status, lower intelligence, and pre-existing psychiatric disorders. ABI often leads to impairments in executive functioning, attention, memory, and social cognition. These deficits can hinder adaptation to prison environments and reduce the effectiveness of treatment. Therefore, early screening and tailored interventions are essential, ideally within the Risk-Need-Responsivity (RNR) model. This model focuses on treating high-risk individuals, targeting criminogenic needs, and adapting interventions to individual capacities. ABI-related consequences span four domains: cognitive, behavioural/personality, mental health, and social functioning. Cognitive impairments may affect memory, language, and executive functioning, either temporarily or permanently. Behavioural changes can include aggression, impulsivity, apathy, and reduced initiative. Mental health problems are highly prevalent, affecting up to 83% of ABI patients, far exceeding general population rates. Social outcomes, such as independent living and participation in society, are also often compromised. In forensic populations, ABI is linked to earlier incarceration, more violent behaviour, and higher recidivism rates. Assessment ideally involves clinical interviews and medical histories, but practical constraints often require screening tools such as the KAP-NAH. Neuroimaging research shows structural and functional abnormalities associated with ABI, including reduced white matter integrity and decreased prefrontal activity, which are linked to impaired cognitive control and potentially to antisocial behaviour. However, ABI is still underrepresented in forensic neuroimaging studies. The dissertation found an ABI prevalence of 55% among forensic inpatients and 51% TBI prevalence among incarcerated men, aligning with previous estimates. These rates may be underestimated due to the historical focus on TBI and reliance on medical records, which overlook nTBI and untreated cases. Despite this high prevalence, ABI-specific interventions in forensic settings remain limited. The findings emphasize the importance of personalized treatment approaches that include ABI screening, neurocognitive assessments, psychoeducation, and strategies to improve motivation and self-awareness. These approaches could enhance treatment engagement and reduce recidivism. There is also a need to improve knowledge dissemination among professionals, as most expressed a desire for more ABI-related resources, while patients reported little attention to ABI in their care. Although ABI was associated with violent crime and identified as a key factor in certain patient subgroups, no significant neurocognitive differences were found between ABI and non-ABI groups. This may be due to overlapping impairments from psychiatric disorders and low educational levels common in forensic populations. Thus, ABI may not add significantly to cognitive impairment but remains relevant due to its link with violent offending. The complexity of ABI in forensic populations reflects interactions with psychiatric disorders, injury severity, timing, and recovery variability. Factors such as childhood ABI, repeated injuries, and socioeconomic background may influence outcomes but were not fully captured in the studies. Finally, fMRI findings revealed subtle neural deficits in individuals with TBI, particularly in brain networks involved in error processing and cognitive control, despite no behavioural differences. Overall, ABI plays a significant yet complex role in forensic populations, underscoring the need for improved screening, research, and tailored interventions.