PERSONALITY CHANGES IN RELATION TO PSYCHIATRIC STATUS FOLLOWING ORBITAL CORTEX UNDERCUTTING.
These findings certainly offer material evidence for the view that psychosurgery leads to a reduction in emotional reactivity. They further indicate that a satisfactory clinical outcome is closely linked with unusually low scores on neuroticism and anxiety and a definite increase in extraversion.

The changes in extraversion occur more slowly and are more variable than those observed for neuroticism and anxiety, and it is noteworthy that only those patients showing marked increases in extraversion in Series B achieve a good psychiatric rating.

At this stage one can only speculate on the relationships between surgery, clinical improvement and changes in the measures used, since no previous study has similarly presented psychometric data in direct relation to the psychiatric findings. It should be stressed that dealing with the data in this way mutually benefits both sets of findings. Nevertheless, it is clear that "level of emotional reactivity" can be given operational definition and used in further research into mental breakdown. It also appears that the complex host of variables which appear to be involved require more sophisticated analysis of a multivariate type.

Finally, this study clearly supports clinical opinions concerning introversion and neuroticism, which have frequently appeared in the literature but which have seldom been based on a quantitative examination.