Few studies have addressed the relationship between dementia and crime. We conducted a study of persons who got a primary or secondary diagnosis of dementia or cognitive disorder in a forensic psychiatric examination.
In Sweden, annually about 500 forensic psychiatric examinations are carried out. All cases from 2008 to 2010 with the diagnoses dementia or cognitive disorder were selected from the database of the Swedish National Board of Forensic Medicine. Out of 1471 cases, there were 54 cases of dementia or cognitive disorder. Case files were scrutinized and 17 cases of dementia and 4 cases of cognitive disorder likely to get a dementia diagnosis in a clinical setting were identified and further studied.
There were 18 men and 3 women; Median age 66 (n = 21; Range 35–77) years of age. Eleven men but no women had a previous criminal record. There were a total of 38 crimes, mostly violent, committed by the 21 persons. The crimes were of impulsive rather that pre-meditated character. According to the forensic psychiatric diagnoses, dementia was caused by cerebrovascular disorder (n = 4), alcohol or substance abuse (n = 3), cerebral haemorrhage and alcohol (n = 1), head trauma and alcohol (n = 2), Alzheimer’s disease (n = 2), Parkinson’s disease (n = 1), herpes encephalitis (n = 1) and unspecified (3). Out of four persons diagnosed with cognitive disorder, one also had delusional disorder and another one psychotic disorder and alcohol dependence. An alcohol-related diagnosis was established in ten cases. There were only two cases of Dementia of Alzheimer’s type, one of whom also had alcohol intoxication. None was diagnosed with a personality disorder. All but one had a history of somatic or psychiatric comorbidity like head traumas, stroke, other cardio-vascular disorders, epilepsy, depression, psychotic disorders and suicide attempts. In this very ill group, the suggested verdict was probation in one case and different forms of care in the remaining 20 cases instead of prison.
Few cases of dementia or cognitive disorder were identified by forensic psychiatric examinations. All but one suffered from a variety of serious mental and medical conditions affecting the brain. Alcohol abuse was prevalent.