Doctors have discovered for the first time a link between criminal behavior in older adults and dementia.  According to a new study, criminal activities including theft, traffic violations, trespassing, sexual advances, and public urination are common early signs of the disease, especially in older adults who are first time offenders. Older adults who begin engaging in criminal behavior or exhibit changes in their personalities could very well be doing so because of damage to the brain, as a result of dementia.

U.S. researchers reviewed the medical records of 2,397 patients diagnosed with Alzheimer's disease or other types of dementia between 1999 and 2012.  They searched for notes about criminal behavior using keywords such as 'arrest,' 'shoplift,' 'driving under the influence,' and 'violence.'  And what the researchers uncovered was that 204 of the patients, or 8.5 percent, had these notes in their records.

They concluded that these behaviors were an early sign of frontotemporal dementia, otherwise known as bvFTD, a rare type of dementia that can lead to inappropriate behavior in social situations and Alzheimer's disease.  They also found that it was often an early sign of primary progressive aphasia (PPA), a type of language-deteriorating dementia.

Of the group that had criminal records, 64 suffered from bvFTD, 24 had PPA, 42 had Alzheimer's, and the rest other forms of dementia. People with bvFTD or PPA tended to be younger, averaging 59 to 63 years old than the Alzeimer's patients, who were an average of 71, when doctors made notes about their criminal behavior.

Over 6.4 percent suffering from bvFTD exhibited physical or verbal violence during their illness compared to 3.4 percent of PPA sufferers and two percent of Alzheimer's sufferers. Dr. Georges Naasan, the leader of the study from the University of California, said that if patients have a family history of dementia, it may be possible to connect criminal behavior to a problem with the brain.

"However, most of these diseases are 'sporadic' meaning that they occur for no identifiable genetic cause and it is difficult to predict," Naasan says. "In general, an early detection of changes in personality, deviation from what constituted a 'norm' for a particular individual, should prompt an evaluation for possible brain causes."

Early signs of the disorders often include personality changes including: disinhibition, lack of empathy, loss of motivation, or even obsessive-compulsive tendencies. 

"It is sometimes hard to wrap our minds around the concept that a specific part of our brain is not functioning properly, leading to behaviours that may range the gamut of disruptive, detached and sometimes criminal," Naasan says. "Family and friends can easily take these behaviour changes personally, but they should understand that it may be the first sign of a disease and should request a medical evaluation," he added.