Criminal behavior revealed as a non-obvious sign of early-stage dementia

Criminal behavior in middle age may indicate the early onset of a neurodegenerative disorder. This conclusion was reached by scientists from the Max Planck Institute for Human Cognitive and Brain Sciences. The research results were published in the journal Translational Psychiatry (TransPsy).

Scientists conducted a systematic meta-analysis of 14 studies covering more than 230,000 people. The studies examined what behavioral changes might precede the development of dementia. It turned out that harassment, property damage, theft, and traffic violations were more common in middle-aged people in the early stages of dementia than in the general population. However, after diagnosis, patients committed such actions less frequently than healthy individuals.

The researchers noted that criminal activity was most prevalent in the behavioral variant of frontotemporal dementia (in more than half of those examined). It was also observed in the semantic variant of primary progressive aphasia (40% of subjects). Primary progressive aphasia (PPA) is a neurodegenerative disease characterized by the gradual loss of speech functions.

Less frequently, crimes were committed by people with vascular dementia and Huntington's disease (15%). The lowest rates were recorded in subgroups of Alzheimer's disease (10%) and parkinsonian syndrome (less than 10%).

The study also showed that men with dementia were more likely than women to demonstrate criminally risky behavior. Moreover, most patients had not previously committed offenses in their lives.

Additionally, scientists studied the structural brain differences associated with this type of behavior. People with dementia who were prone to criminal behavior showed more pronounced atrophy of the temporal lobe. Such changes can lead to impulsivity and apathy. The authors of the study explained that risky criminal behavior can also be caused by disinhibition - a reduced ability to control emotions and decision-making speed.