|Vol. 6, No. 3, 2000 Page 6&7|
A SPECT/MRI study by Swedish researchers adds to evidence that the brains of violent offenders are often abnormal.
Henrik Soderstrom and colleagues studied 21 subjects (median age 27) convicted of impulsive violent crimes, comparing their SPECT and MRI scans to those of 11 healthy control subjects. None of the criminals had a history of major mental disorder, previous sly diagnosed brain injury, or neurological disease, and all those with substance abuse problems had undergone detoxification.
"Overall," the researchers say, "the MRI examinations revealed subtle, although most likely nonspecific, changes in a higher frequency than expected in this age group." SPECT scans, they say, revealed abnormal findings in all but five of the criminal grou up. Abnormalities included decreased blood flow to the hippocampus, the left white frontal matter, and the right angular gyrus and medial temporal gyrus, and significant increases in blood flow to both sides of the parietal association cortex.
Their findings, Soderstrom et al. say, are consistent with previous studies suggesting that reductions of blood flow to the prefrontal cortex may correspond to executive dysfunction and poor impulse control, and that temporal lobe dysfunction may result i in violent behavior. In addition, they say, increased blood flow in the parietal association cortex may be associated with the abnormal responses to sensory stimuli reported in studies of individuals with attention deficits.
The researchers conclude, "SPECT imaging has, as no other diagnostic tool used in forensic psychiatry today, demonstrated a consistent pattern of aberration from the normal in non-psychotic perpetrators of crimes of extreme aggression and lack of impulse control."
"Reduced regional cerebral blood flow in non-psychotic violent offenders," Henrik Soderstrom, Mats Tullberg, Carsten Wikkels”, Sven Ekholm, and Anders Forsman, Psychiatry Research, Vol. 98, 2000, pp. 29-41. Address: email@example.com.