Apter attempts to correlate psychodynamic mechanisms with biological data, and approaches this problem by attempting to produce changes in the physiology of chronic schizophrenic patients and to study the behavioral changes brought about by them. His work is based on the principle that activities of the ego undergo degradation when cortical functions are disturbed and are reconstituted as these functions improve, as shown by Hughlings Jackson. The adaptive pattern results from the interplay of internal and external processes. When external circumstances produce so much stress that the adaptive pattern cannot continue to protect against mounting anxiety, the organism may either regress or be propelled forward to a better adaptive response. The schizophrenic reaction is a disorder of adaptation, with characteristic disabilities, which is available to every member of the human species. It may be reversible or irreversible, according to the time of onset of the psychosis and its duration.