Schizophrenia is known to be one of the most significant reasons of neurocognitive dysfunction (Satan’s voice or hallucination) and ultimately homicide by that dysfunction. However, not enough is known about how offenders with schizophrenia perform on neuropsychological measure.
Inspired by lack of study in such context, the neuropsychology journal <Murder and psychosis: Neuropsychological profiles of homicide offenders with schizophrenia> by John Straton, Michael Brook, and Robert Hanlon aims to depict the neuropsychological profiles of homicide offenders with schizophrenia.
This research conducts several psychological and statistical tests with 25 people diagnosed with schizophrenia who had killed another person (Of course, we will focus on their statistical analysis of data).
With the results of various psychological tests, this journal employs standard scores(SS), T-scores, scaled scores(ss), and Z-scores to characterize the neurocognitive profile of the sample. At last, they were linearly transformed to uniform z-scores for evaluation of the relative degree of impairment for different cognitive abilities.
Then, that sample was divided according to the presence or absence of God/Satan/demon-themed psychotic content for a supplementary analysis. The differences in those two groups were evaluated two-tailed independent t-tests. When t-tests cannot be applied, Mann–Whitney U-tests were deployed. Other clinical and criminological variables were analyzed by chi-squared test.
(Detailed explanation for those tests will be uploaded in the separate catalog of this page.)
The results of that analysis were divided into three major sections: General Characteristics of the sample, Neurocognitive Characteristics of the sample, and GSD Psychosis group differences. Generally, the participants were determined to be the patients of schizophrenia using the forensic evaluation. Moreover, IQ score of the homicide offenders with schizophrenia was at the margin of the mean IQ score which is 79.
In terms of GSD, one-third of the participants disclosed GSD symptoms while diagnosis (GSD stands for God/Satan/demon). Surprisingly, GSD group performed higher average IQ scores than NGSD (Non-God/Satan/demon group) on selected problem solving, on encoding, and on retrieval of non-contextual verbal information. Moreover, GSD group was greatly more apt to have perpetrated the planned murder than NGSD group was. Those in GSD group have experienced more often hallucinations than those in NGSD group have.
Comprehensively, the paper supports the hypothesis of epidemic neurocognitive flawed among murderers with schizophrenia. Through this paper, the author of this research emphasizes the importance of recognizing the combination of low IQ, attentional-executive dysfunction, auditory hallucinations, paranoid delusions and prior criminal history that homicide offenders have. In addition, the offenders typically killed within domestic reach, hence these results accentuate the importance of family intermediary.