Dementia and cognitive disorder identified at a forensic psychiatric examination - a study from Sweden

Understanding the impact of dementia has not been in focus in forensic psychiatry since criminal behaviour often starts at young age. Few studies have focussed on the mental condition of elderly criminals. A study from California showed that elderly criminals often were treated more harshly initially but more often got a milder verdict [1]. A Swedish study found that only <3% forensic psychiatric examinations concerned persons 60 years or older [2]. In 7% of those, dementia was found. In a register-based study from Finland, homicide offenders aged 60 or older had less drug dependence and personality disorders and more dementia and physical illnesses than younger homicide offenders [3]. In forensic psychiatric examinations in Turkey, most persons >60 years of age were diagnosed with schizophrenia or delusional disorder [4]. In South Carolina, violent crimes were common among persons >60 years of age that went through a forensic psychiatric examination [5]. In Korea, less than 1% of the patients in a forensic psychiatric hospital were diagnosed with dementia: Alzheimer patients being convicted for theft and patients with vascular or alcohol-related dementia for multiple violent crimes under influence of alcohol [6].

There are a few reports on persons with dementia committing murder [7, 8]. In murder-suicide cases by elderly couples, the victim often suffers from dementia and not the spouse committing the murder [9, 10].

Does dementia actually decrease the risk of committing crimes? Neurocognitive symptoms like memory impairment, reduced executive function, lack of judgement and language difficulties are hall-marks of dementia. Symptoms vary over time and with the type of dementia, comorbid diseases, medication, environment and care provided. Symptoms can separately or in combination contribute to criminal behaviour and actions.

Some persons with dementia become withdrawn and careful since they experience their shortcomings. Reduced executive function, that is common in Alzheimer’s disease, results in a passive behaviour, not likely to enhance planning and organizing a crime.

Focal prefrontal damage seems associated with an impulsive subtype of aggressive behaviour and persons with Frontal Lobe Dementia are at increased risk for violent crimes [11]. In a retrospective medical record review from a memory and ageing centre in California, patients with the behavioral variant frontotemporal dementia and semantic variant of primary progressive aphasia more often committed crimes than those with Alzheimer’s disease [12].

When a Swedish Court of Law finds a person guilty of a crime and the verdict is prison, it is possible to presentence a forensic psychiatric examination if the person has shown signs of mental disorder. The forensic psychiatric examination should establish whether the person suffered from a “severe mental disorder”, a judicial concept, at the time of the crime, and at the time of the examination. From a forensic point of view, a “severe mental disorder” is not related to diagnoses but to effects of disorders: 1) Psychotic effects or 2) Severe depression with suicidal behavior at the time of the crime or 3) Severe personality disorder with recurrent episodes of psychotic behavior and decreased psychosocial functioning or 4) Mental disorder with marked compulsiveness and decreased psychosocial functioning or 5) Severe dementia, severe mental retardation and severe brain damage. Mental disorders may be considered severe by the public and by the general health care system and but not from a forensic psychiatric point of view. If the person was in a state of severe psychiatric disorder at the time of the crime, the verdict can be forensic psychiatric care instead of prison. The court should also decide on whether cessation of forensic care be decided by the forensic psychiatrist or by a court procedure (“forensic care with separate discharge review”).

The National Board of Forensic Medicine is responsible for the examinations, not the health care system. About 500 persons annually in Sweden undergo a forensic psychiatric examination. A forensic psychiatric examination is performed by a team of forensic psychiatrists, psychologists, forensic social investigators and nursing staff.

If a crime is committed by a person with dementia or other severe mental disorder, the Swedish Law of Code of Judicial Procedure [13] allows the court to abstain from prosecution. There are, however, no statistics about how often this occurs. Probation, a non-custodial sanction that places the convicted person under supervision, is another possible verdict.

Since the number of elderly and persons with dementia increase, it is likely that there will be more crimes in this group.

Cases were selected from the database of the Swedish National Board of Forensic Medicine including all Sweden. There were a total of 1471 forensic psychiatric examinations in 2008–2010. All cases from 2008 to 2010 with a primary or secondary diagnosis of dementia or cognitive disorder according to the DSM-IV classification [14] (290.0, 290.10–13, 290.20–21, 290.3, 290.40–43, 291.2, 292.82, 294.0–1, 294.8–10, 331.0–1, 631.0) were selected.

Since the criteria for dementia are inexact, we included cognitive disorder since we believed that there might be cases of dementia in this group. A total number of 54 cases were found, and the complete files were further scrutinized by two researchers with extensive clinical experience of dementia.

The first part of the scrutiny was to find the cases that would correspond to a dementia diagnosis in a clinical setting, and 27 cases were excluded. Out of the 27 cases excluded, 8 persons had 294.9 (cognitive disorder not otherwise specified) as primary diagnosis, and 18 persons had 294.9 (cognitive disorder not otherwise specified) as secondary diagnosis. In one case, the diagnosis was 294.8 (amnestic disorder not otherwise specified) as secondary diagnosis.

Five additional cases with DSM IV diagnosis 294.8–9 (amnestic disorder not otherwise specified) (cognitive disorder not otherwise specified) were excluded since the dementia work-up was incomplete from a clinical point of view or the individual was using drugs. In a clinical setting, those patients would be welcome for a dementia work-up after a period of no abuse. It thus remained a total of 22 cases. In one case, the same individual had undergone two forensic psychiatric examinations with the same result. One of them was therefore excluded yielding a total number of 21 cases.

The conclusions from the extensive psychological testing and the complete notes from physicians, nursing staff, social workers, and occupational therapists were scrutinized. Detailed data from 21 case files were extracted from the case files: Age, gender, year of birth, marital status, number of children, living conditions, education, profession, need of help with activities of daily life, smoking, use of alcohol and drugs at the time of the crime and otherwise, the current crime, previous crimes, all relevant previous and present medical data including pharmacological treatment and the results of a magnetic resonance tomography (MRI), computerized tomography (CT) or cerebral blood flow (CBF) of the brain, electroencephalogram (EEG), and laboratory tests, results from the neuropsychological tests and observation (impaired memory, impaired executive functions and judgement, impaired ability to understand instructions, impaired knowledge of time, hallucinations, delusions, delirium, aphasia, dyscalculia, prosopagnosia, agnosia, apraxia, Mini Mental State Examination score (MMSE) all diagnoses in the current and previous forensic psychiatry examination, former forensic psychiatric care, verdict and recommendation from National Board of Forensic Medicine. Due to the small size of the study, statistics were not needed.

The most striking finding of this study of forensic psychiatric diagnoses was that there were very few persons being diagnosed with dementia. This is in agreement with studies from countries like Finland, Korea, the U.S. and Turkey [3‐6].

Although dementia primarily occurs at old age, half of the persons were younger than 65 years. Dementia of Alzheimer’s type constitutes approximately two thirds of all cases of dementia, but this was not reflected in the group of forensic psychiatric examination. In our study, only 2 persons (10%) had Dementia of Alzheimer’s type, one of whom also had alcohol intoxication at the time of the crime.

Alcohol is a well-known risk factor for violent crimes world-wide. Although we excluded those with alcohol abuse at the time of the forensic psychiatric examination, 48% of the cases had alcohol-related diagnoses. The ageing brain and especially a brain with a disease or previous trauma are also more sensitive to alcohol.

It is not surprising that many of the persons had a history of mental disorders, but all but one also had a history of serious medical disorders and/or traumas. Six persons (29%) had a history of head trauma with concussion and three additional persons (14%) had experienced traumatic brain haemorrhage. Six persons (29%) had a history of stroke and additionally five persons (24%) other evidence for cardiovascular disorder. Two persons (5%) had sequel after meningitis or encephalitis and seven persons (33%) had epilepsy. Three persons (14%) had a previously established diagnosis of dementia and 38% had previously gone through a clinical dementia work-up. The above-mentioned conditions are also risk factors for dementia. In spite of serious medical conditions, few patients were taking medication regularly.

There was no case of personality disorder in this study, perhaps due to small study size. Personality disorder may, however, in accordance with a Finnish study of psychopathy be less prevalent in elderly criminals compared to younger ones [3]. It is also possible that other diseases including dementia overshadowed a personality disorder.

Prefrontal damage seems to predispose for impulsive, aggressive behaviour and persons with frontal lobe dementia are at increased risk for violent crimes [11, 12]. There were, however, no cases of frontal lobe dementia in this material, perhaps due to the small numbers.

Our findings underline the importance of protecting the brain from trauma, disease, and alcohol as far as possible, which concerns every practicing physician. Medical help for alcohol abuse should be available also for elderly and persons with dementia. Many geriatricians and old age psychiatrists would appreciate collaboration with colleagues in forensic psychiatry when patients with dementia become dangerous. With the growing elderly population, forensic psychiatry could benefit from collaboration with those who work with dementia on a daily basis, and more knowledge about dementia and cognitive disorders should be included in the curriculum for forensic psychiatrists in training.

In conclusion, we found that forensic psychiatric examinations seldom lead to a dementia diagnosis, and when it does, the majority of persons have a number of medical conditions affecting the brain. Alcohol is a strong risk factor for committing crimes in persons with or without dementia.

The crimes are mostly impulsive-aggressive as opposed to premeditated. A person with dementia may easily misunderstand a situation and act improperly. We believe that in many cases where persons with dementia are involved in crimes, it is apparent for anyone that they do not fully understand. It is likely that many cases are never taken to court, although no statistics is available on waiver of prosecution. 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. Even without having committed crimes, those persons were in need of a lot of attention and care.