Premorbid self‐disorders and lifetime diagnosis in the schizophrenia spectrum: a prospective high‐risk study

Aim The notion of a disordered self as a core disturbance of schizophrenia was proposed in many foundational texts. Recent studies, spurred by the development of the E xamination of A nomalous S elf‐ E xperience ( EASE ), seem to indicate that self‐disorders are a specific manifestation of schizophrenia vulnerability. Follow‐up studies of help‐seeking, prodromal and first‐admission patients have demonstrated the utility of self‐disorders for predicting later schizophrenia‐spectrum disturbance. We wished to extend these findings by gauging the predictive value of self‐disorders in a premorbid, non‐clinical population at high risk for schizophrenia. Methods Children from the C openhagen H igh‐ R isk P roject with high‐genetic risk for schizophrenia ( N  = 212) were assessed premorbidly (average age = 15), and diagnostically re‐evaluated after 10 and 25 years. Since the EASE was not available at the time of premorbid assessment, we hypothesized that a proxy scale drawn from the Minnesota Multiphasic Personality Inventory ( MMPI ) could distinguish those who later developed a schizophrenia‐spectrum disorder ( N  = 68) from those who remained healthy ( N  = 64). The S elf‐ D isorder Scale comprised 32 items whose content suggested an aspect of self‐disorder as measured by the EASE . Results Premorbid Self‐Disorder Scale scores significantly predicted lifetime schizophrenia‐spectrum diagnosis in the high‐risk cohort. Although there was considerable item overlap between the new scale and an existing MMPI scale (psychoticism), the overlap did not account for the Self‐Disorder Scale's predictive efficacy. Conclusion The results support the notion of self‐disorders as a core vulnerability feature in schizophrenia, detectable premorbidly in those developing later schizophrenia‐spectrum disorders.