Anomalous subjective experiences are thought to be intrinsic to schizophrenia and considered as constituting the phenotypic validity anchor of the schizophrenia spectrum concept.

Although neglected in modern psychiatry, due to the dominating behaviouristic approach, they nevertheless have been thoroughly investigated in continental European psychiatry, where it has been shown that their presence antedates future psychosis. Anomalous experiences of self-awareness (self-disorders) are a sub-group of subjective pathology, and has been hypothesized to constitute a core phenotype of schizophrenic spectrum disorders. Our research team has participated in the development of a self-disorder scale, EASE, based on empirical studies, clinical experience, phenomenological philosophy and existing psychopathological scales. A part of the EASE-items is overlapping the BSABS. These common psychopathological phenomena have been shown to be predictors of later development of schizophrenic psychosis. Results from three separate studies making the basis of the EASE are presented.

Drawing on the results of our own three separate empirical studies the distribution of self-disorders in patients with schizophrenia, psychotic bipolar illness, schizotypal disorder and other mental illnesses, and relatives with no mental illness is described.

It is shown that self-disorders are common and equally frequent in schizophrenia and schizotypal disorder, and significantly less common among patients with psychotic bipolar illness and other mental illnesses, and almost absent in the relatives without mental illness.

The results support the schizophrenia spectrum hypothesis and points to self-disorders as a phenotype of schizophrenia-spectrum disorders. Self-disorders appears to be possible predictors of schizophrenic prodromal states.