When the first crime is a symptom: criminal signals of early dementia revealed

A recent meta-analysis of 14 studies involving 236,360 people from the US, Sweden, Finland, Germany, and Japan showed that criminal or risky behavior may be the first sign of dementia, especially in cases of frontotemporal dementia and its linguistic variants.

The results of the study were published in the journal Human Brain Mapping. 

Apparently, the early stages of some types of dementia disrupt personality and behavioral barriers, leading to impulsivity, aggression, theft, or even aggression towards people or animals — often for the first time in a person's life. 

The frequency of such manifestations is highest in the behavioral variant of frontotemporal dementia (bvFTD) — more than 50%, followed by the semantic variant of dementia — about 40%. For comparison: in vascular dementia and Huntington's disease — approximately 15%, in Alzheimer's disease — about 10%, and less than 10% in Parkinson's syndromes. 

Interestingly, the likelihood of criminal behavior is significantly higher before the official diagnosis than after: in the early stages of the disease, especially in the stages of early cognitive or behavioral decline, it exceeds the rates of the general population, and then falls below the average level.

A noticeable gender gap has also been identified: according to the data, men are more likely to exhibit such behavioral changes — after diagnosis, criminality in men exceeds that in women by 4 times in bvFTD and 7 times in Alzheimer's disease.

The brains of such patients often show severe atrophy of the temporal lobes, which is associated with a loss of inhibitions—an inability to control emotions and impulses.

Researchers emphasize the importance of recognizing such behavior as a possible early sign of dementia, thereby speeding up diagnosis and starting treatment. Dialogue between the medical and legal communities is also necessary to reduce the stigmatization of patients and adapt legal proceedings to take these disorders into account.

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