By Bahar Gholipour, Staff Writer
Published: 09/06/2013 07:40 AM EDT on LiveScience
A 49-year-old man in Brazil survived a stroke but underwent a strange personality change afterward -- he developed "pathological generosity," according to a report of his case.
His willingness to give liberally to others - including people he barely knew -- dramatically changed his life. He would spend his money on children he met on the street, buying them soda, candies and junk food, his wife told the doctors. Mr. A, as the man is called in the case report, became unable to manage his financial life, or resume his job as a department manager within a large corporation.
The stroke apparently left Mr. A with "excessive and persistent generosity," the researchers, led by Dr. Leonardo Fontenelle from the Federal University of Rio de Janeiro, concluded in the report published Aug. 20 in the journal Neurocase.
"Stroke can cause a whole variety of neuropsychological and behavioral changes," said Dr. Larry Goldstein, neurologist and director of the Stroke Center at Duke University, who wasn't involved with the case. "Although the observation of personality change is not that unusual, this particular one is apparently novel," he said.
Very often, a behavior change after a stroke depends on the extent of injury and the location of the injury in the brain, Goldstein said.
How stroke affects personality
A stroke occurs when a blood clot blocks the blood supply to the brain, or when a blood vessel in the brain bursts. Brain damage caused by low oxygen supply can lead to emotional changes, most commonly depression, but strokes have also been known to cause pathological laughing or crying, or neglect syndrome, in which people don't recognize one side of their visual field.
Understanding exactly what change in the brain was driving Mr. A's excessive generosity is very interesting for scientists, especially because the condition is in many respects the opposite of disorders such as hoarding and sociopathy, the researchers said.
Doctors determined Mr. A's stroke occurred in a subcortical region, (below the cerebral cortex, where higher-level thinking occurs), and the damage could have affected brain areas associated with regulating normal behaviors.
But knowing the location of a stroke doesn't necessarily predict the behavioral change. The networking that happens in the brain means there are often effects in areas of the brain not right next to the injury, Goldstein said.
Studies have pointed to a couple of brain structures as being involved in acts of generosity, such as anonymously donating to charities. These brain structures include the brain's reward system, the researchers said.
A life forever changed?
Mr. A's pathological generosity may provide new insights into which brain areas affect "the delicate balance between altruism and egoism, which make up one of the pillars of ordinary social motivation and decision making," the researchers said.
Other instances of excessive benevolent behavior have been seen in cases of people with mania, Parkinson's disease treated by certain medications, and forms of dementia.
When doctors carried out a psychological evaluation of Mr. A, they didn't find any evidence of manic symptoms or dementia. Mr. A. reported being depressed, forgetful and unable to pay attention. He also showed some behaviors that have been linked to damage in the frontal lobe of the brain, including lack of persistence and planning, and impaired judgment, according to the report.
A CT scan showed blood flow to several brain regions, including areas in the frontal lobe, was low. These regions, although far from the bleed focus, are connected with it by neural pathways. The damage in these pathways might have disrupted the interplay of neural systems that underpin key dimensions of personality, the researchers said. [Image: CT scan of the brain's blood flow]
Mr. A was put on medication to treat his depression. After two years, he said he felt cured, and stopped the depression treatment, but his pathological generosity was unchanged. He was aware of changes in his behavior. According to the researchers, he often claimed, "I saw death from up-close, now I want to be in high spirits."
When doctors asked whether he intended to resume his former job, he replied that he had already worked enough, and that it was now time "to enjoy life, which is too short."