Are Criminal, Socially Inappropriate Behaviors Associated With AD, Frontotemporal Dementia?

^{By Julie Gould}

Adults with frontotemporal dementia (FTD) and Alzheimer disease (AD) are at an increased risk of criminal and socially inappropriate behaviors, according to new study findings. Notably, criminal behaviors may be more recurrent in patients with FTD versus AD.  

“Criminal and socially inappropriate behavior is encountered among patients with dementia, and it is sometimes the first sign of a dementing disorder,” lead researcher Madeleine Liljegren, MD, PhD, Lund University, and colleagues wrote online in JAMA Network Open.   

Dr Liljegren and her colleagues examined patients with a postmortem neuropathologic diagnosis of AD (n = 101) or frontotemporal lobar degeneration (n = 119). The average age at disease onset was 63 among the patients examined.

According to the findings, instances of criminal behavior was found in 65 of the 220 patients—15 patients with AD and 50 with FTD. Further, recurrence of criminal behavior was significantly higher in the FTD group (89.0%) than in the AD group (53.3%). Finally, the research team identified 57 patients with AD who demonstrated socially inappropriate behavior and 89 with FTD.  

To better understand the key takeaways of this study as well as knowledge gaps that still exist, we spoke with Dr Liljegren.  

Please tell us about yourself and your research interests.  

I am a medical doctor/psychiatry resident. I obtained my PhD from Lund University, Sweden under the supervision of Dr Elisabet Englund, neuropathologist. As a medical student I had the opportunity to do an exchange semester at the Memory and Aging Center, UCSF. The work at UCSF, together with Dr Bruce Miller, inspired me to further study the relationship between criminal, antisocial behavior, and dementia. The neurobiological explanation for psychiatric problems is something that I find especially interesting. In the future I hope to combine my interest for psychiatry and neurology and become a neurologist too.  

Prior to your study, what was known regarding the association between criminal behavior, socially inappropriate behavior with dementia and Alzheimer disease?  

Previous studies (including from our research group, see Liljegren et al. JAMA Neurology 2015) have shown a connection between criminal behavior and frontotemporal dementia (FTD). This study is unique in that we studied deceased patients, something that means we are 100% sure of the dementia diagnosis, which is not always established while the patients are alive. Protein pathology in relation to criminal behavior has, to our knowledge, never been examined before. It is well known that FTD patients tend to behave in odd and socially inappropriate ways. This can also affect people with Alzheimer disease (AD) although it is not as common as in FTD.

Following your study, how did criminal behavior and socially inappropriate behavior relate to patients with dementia and AD? Can you briefly summarize your key study findings?  

We studied 220 deceased patients with AD or FTD, who had been monitored at the Memory Clinic in Lund between 1967 and 2017. Of these, 30% had committed a criminal offence – 15 per cent of the total number of patients who had AD and 42 per cent among those who had FTD. The latter group committed repeated criminal offences to a greater extent than the AD group. When examining socially inappropriate behavior such as excessively loud laughing or unexpected shouting, the FTD group was also overrepresented (75%), compared with the AD group (56%). In addition, we observed that the likelihood of committing criminal acts was nine times higher among patients with FTD who had accumulations in the brain of certain abnormal proteins, above all TDP-43, compared with those who had accumulations of tau protein. The TDP-43 proteins seem therefore to be particularly associated with developing criminal behavior among people with FTD.

How can these findings be used in the clinical diagnostic process? 

These findings might help in the clinical diagnostic process, especially when the clinical picture is unclear, and the differential diagnoses are difficult to distinguish. 

How can health care providers take these findings and implement them into practice? What are the major takeaways for health care providers?  

Criminal and socially inappropriate behaviors could be signs of dementia. When previous law-abiding citizens start to behave in an odd way or even commit crimes, we suggest that they be screened for neurodegenerative disorders. This could potentially lead to a shorter time from symptom onset to diagnosis and hence proper care in time. Frontotemporal dementia can also occur in younger people and it can often take a long while before there is a correct diagnosis. That is why it’s important that relatives, healthcare services, the police and the entire legal system respond to altered social and criminal behavior and provide assistance to enable these people to get medical care. 

What knowledge gaps still exist between these behaviors and dementia or Alzheimer disease?  

The brain and neurodegenerative disorders are extremely complex. There is a lot more to be done in the field. There is some exciting new research where scientists have tried to approximate certain areas, or networks, in the brain that could be responsible for the generation of criminal behavior (e.g. Darby RR, Horn A, Cushman F, et al. Lesion network localization of criminal behavior. Proc Natl Acad Sci U S A. 2018;115(3):601-606.). One of the more interesting questions that have arisen for me during these years is: Will the advances in neuroscience be the end of the expression of free will? Frontotemporal dementia patients can sometimes verbalize that their actions are wrong but proceed with criminal behavior. This is especially problematic when FTD patients are facing criminal charges. Would we say that they chose to act this way? Or were the decisions they made only a result of their disease? 

Is there anything else you would like to add? 

Prospective studies, including imaging, with neuropathological follow-up is required. We recommend that research include judicial outcomes for these patients. If these patients could get help early in the disease it would be beneficial for the patient, the patient's family and society in general. 

Reference:

Liljegren M, Waldo ML, Santillo AF, et al. Association of Neuropathologically Confirmed Frontotemporal Dementia and Alzheimer Disease With Criminal and Socially Inappropriate Behavior in a Swedish Cohort [published online March 29, 2019]. JAMA Netw Open. 2019;2(3):e190261. doi:10.1001/jamanetworkopen.2019.0261 

Photo Courtesy: Ingemar Walldén.