Background: Basic self-disturbance (BSD) is proposed to constitute the clinical core of schizophrenia spectrum disorders, including prodromal states and schizotypy. Anomalous self-experiences (ASEs) are suggested as phenotypic variants of BSD, representing markers of schizophrenia vulnerability. However, ASEs are not restricted to the schizophrenia spectrum, but may also occur in non-psychotic states like depersonalization disorder (DPD). It is unclear to what extent the prevalence and nature of ASEs are differing between the two conditions. The main aim of this paper is to assess and compare ASEs in both conditions, based on literature and two illustrating cases. This might expand the understanding of these phenomena, and strengthen the basis for clinical differentiation.
Methods: One patient with schizotypal personality disorder (SPD) and one with DPD were selected from an ongoing clinical high-risk (CHR) for psychosis study. ASEs were assessed with the Examination of Anomalous Self-Experience (EASE) and analyzed according to the two central dimensions of BSD: diminished self-affection and hyperreflexivity, as well as according to prototypical aspects of depersonalization. The cases were also analyzed and compared with respect to chronology, other symptomatology, and psychopathological pathways.
Results: Both cases revealed ASEs reflecting the central dimensions of BSD as well as prototypical aspects of depersonalization. Only the SPD case however, linked ASEs to psychotic-like ideas of external influence and control. The symptoms had an insidious early childhood onset with no obvious triggers in the SPD case, and an abrupt adolescence onset triggered by second-time cannabis use and panic anxiety in the DPD case.
Conclusions: The similarities and differences in ASEs, symptomatology and developmental pathways of the two cases might be accounted for by an updated model of self-disorders. The model proposes that schizophrenia manifests as a result of a combination of early “primary”-onset ASEs, reflecting disturbances in early neurodevelopment, and later occurring, “secondary” ASEs of a more defensive-protective character. In line with this, the DPD case may be characterized only by secondary ASEs and thus better protected against psychotic decompensation than the SPD case, tentatively affected by a combination of primary and secondary ASEs.