Thus, we can use impoverished environment as a model of reduced local connectivity without neuronal loss. Though we lack systematic studies, there is no evidence to date that, without increasing the level of stress, impoverishment is sufficient to increase the risk of schizophrenia. Neither is there any observation of the topography of gray matter reduction in nonpsychiatric subjects living in an impoverished environment. However, turning the question around, the observation that environmental factors possibly induce cortical atrophy could lead to another interpretation of the anatomical problem in patients. It may be that some of the gray matter reduction observed in patients corresponds to their way of living, eg, avoiding social contact could simulate the cortical shrinkage seen in rats after social deprivation.10 In fact, it might be that the so-called hypotrophy could be explained in the same way. Relatives could display gray matter reduction because of behavior related to an overt or subclinical schizoid or schizotypal personality disorder. There is much less argument for environmental effect on white matter, but one should consider looking at it more closely.
