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DEMENTIA STUDY OFFERS INSIGHT INTO ANTISOCIAL, IMPULSIVE BEHAVIOR
A new study of patients with dementia offers evidence that abnormalities of
the frontal and temporal lobes can predispose an individual to antisocial or
violent behavior. The study's findings, authors B. L. Miller et al. say,
"offer a compelling reason for continuing the exploration of possible
structural and/or functional abnormalities in the brain associated with
criminal activities."
Miller et al. studied the frequency of antisocial behaviors in two groups of
patients: 22 with dementia due to progressive dysfunction of the anterior
frontal and temporal cerebral lobes, and 22 with Alzheimer's disease, which
primarily affects the hippocampus and posterior parietal and temporal lobes.
Both groups were diagnosed through neuropsychological tests, clinical
evaluations, and SPECT (single photon emission computerized tomography) and
magnetic resonance imaging studies. The researchers determined the number of
antisocial acts committed by each patient by questioning patients and their
families and reviewing subjects' medical records.
The researchers found that ten of the 22 subjects with frontal-temporal
dementia (FTD) had histories of socially disruptive behaviors. "Three FTD
patients were arrested," they say, "[and] two others had relatives who
prevented their arrest by convincing authorities that the FTD subject was
'sick'." Behaviors reported in the FTD patients included stealing, physical
assaults, sexual comments and advances, indecent exposure, public urination,
unethical job conduct, and a hit-and-run. In comparison, only one of 22
patients with Alzheimer's disorder had a history of socially disruptive
behavior.
Because nearly all of the subjects were classified as having only mild
dementia at the time of the study, Miller et al. say, "the behaviors cannot
be attributed to confusion or severe dementia in either group." They add
that the antisocial behaviors seen in the FTD group also cannot be explained
by the theory that brain dysfunction simply magnified existing personality
traits. Relatives of the FTD patients, the researchers note, described them
as "responsible, high-functioning adults" before the onset of their
dementias.
The researchers say their study "supports a relationship between frontal-
temporal dysfunction and certain types of antisocial activity." They suggest
that their findings are relevant to criminal research, pointing out that
"recent work suggesting a strong anatomical basis for murder, with
perpetrators demonstrating marked frontal (64.5%) or temporal (29%) deficit,
has been reported." (See related article, Crime Times, Vol. 1, No. 4, Page 1.)
"The present study," Miller and colleagues say, "may have relevance to the
question raised so often in moral and legal arenas, 'Why in the world would
this person have behaved in a manner so unlike himself?'"
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"Aggressive, socially disruptive and antisocial behaviour associated with
fronto-temporal dementia," B. L. Miller, A. Darby, D. F. Benson, J. L.
Cummings, and M. H. Miller, British Journal of Psychiatry, 170,
1997, pp.
150-155. Address: B. L. Miller, Professor of Neurology, Harbor-UCLA Medical
Center, 1000 W. Carson Street, Torrance, CA 90509, fax (310) 618-1273.
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