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Abstract
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Three groups of neuropsychiatric out-patients, homogeneous according to parameters of violent behaviour, were identified in a previous study using a cluster analysis procedure and compared in this study on psychometric variables. These groups were (a) a group manifesting frequent, impulsive violence (n = 35), (b) a non-violent group (n = 57), and (c) a group whose violent behaviour was much less frequent and severe than in the first group, and more provoked (n = 31). Impulsively violent patients showed language and visual-perceptual deficits, but no other neuropsychological or intellectual deficits. The MMPI F, K and Ma and MacAndrews Alcoholism scales and a perceptual organisation factor derived from the Holtzman Inkblot Test significantly discriminated groups. Results of this and the initial study have implications regarding psychological aspects of aggression and underlying biological mechanisms.
VioLit summary:
OBJECTIVE:
The purpose of this study by Mungas was to compare three groups of neuropsychiatric outpatients on psychometric variables in order to identify psychological parameters of violent behavior.
METHODOLOGY:
The author followed a quasi-experimental design in which subjects were matched to three groups using a cluster analysis procedure. The sample consisted of 123 neuropsychiatric outpatients who were divided into three groups. Group One was defined by frequent, poorly provoked violence (n=35). Group Two had no history of violent behavior (n=57). Group Three was defined by mild to moderate, relatively well provoked violence (n=31).
The subjects were then administered a battery of neuropsychological tests of cognitive abilities in addition to the Minnesota Multiphasic Personality Inventory (MMPI) and the Holtzman Inkblot Technique (HIT). The author was testing four areas of cognitive functioning: (1) attention and concentration, (2) language-related abilities, (3) visual-perceptual abilities, and (4) memory and new learning. Factor analysis was performed in order to reduce the number of variables from neuropsychological testing into a smaller number of underlying factors with greater reliability than individual variables. Independent principal components analyses were conducted on each of the four sets of variables and components with eigenvalues greater than 1.0 for possible rotation were retained. One principal component for both language and visual-perceptual variables were retained for oblique rotation. Finally, three principal components of memory tests were retained. The author created an overall index of cognitive functioning by performing a second order principal components analysis of the component scores of each of the above components. The three sample groups were then compared using these seven components as dependent variables.
FINDINGS/DISCUSSION:
The author considered both the age and sex of the subjects to be significant covariants of the dependent variables while their education was not used as a covariate. A one way ANOVA showed significant group differences from the MMPI data. The HIT variables were reduced to six components of which only the "perceptual organization" component significantly discriminated groups. The author found that frequently violent individuals displayed abnormalities in language and visual-perceptual skills. This same group also demonstrated abnormalities on a number of psychopathology parameters and an increase in arousal level and reactivity as well as a predisposition toward substance dependency. Although these findings appeared to lend insight into conceptualizing the mechanisms underlying violent behavior, the author suggested that they should be interpreted with caution. First, these results were only applicable to cases of frequent, poorly provoked, impulsive behavior. Second, since all the individuals selected fro this sample had histories of both neurological and psychiatric abnormality, these factors were most likely overrepresentative in comparison to the general population. Third, with the absence of a control group, other characteristics related to violence in a less specific way could not be identified. Fourth, the violence committed by the subjects in Group One was not as extreme as one might find in individuals incarcerated for multiple violent crimes. Finally, since this was a retrospective study relying on available data the author cautioned that there could have been other variables which did not appear in the data.
The author did not find that deficits of language and visual-perceptual skills could be linked to differences in overall level of intellectual functioning. Two hypotheses were offered, however, to explain the language deficits in Group One. One possibility was that poor language skills resulting from either "dominant hemisphere dysfunction or from psychosocial or cultural factors, could directly relate to violent behavior through precluding more adaptive, verbal mediation of behavior in emotionally charged situations" (p. 184). Another possibility was that dominant hemisphere dysfunction could be a causative factor which would suggest that language deficits, while correlating with violent behavior, might not be causally related. Although the relative contribution of biological and psychosocial factors to the poor language skills was not determined, the author suggested that poor language skills might have an effect on violent behavior. The MMPI scales revealed that an underlying psychological abnormality which predisposes individuals to both alcoholism and violent behavior may exist. The author concluded by suggesting that pathological past learning experience is a primary factor leading to violent tendencies.
AUTHOR'S RECOMMENDATIONS:
The author suggested that future research into psychometric correlates of violent behavior might extend the findings of this study to resolve some of the inherent methodological problems.
N1 - Call Number: F-408, AB-408
KW - Adult Offender
KW - Adult Violence
KW - Mentally Ill Adult
KW - Mentally Ill Offender
KW - Mentally Ill Patient
KW - Biological Factors
KW - Neurological Factors
KW - Violence Causes
Language: en |