This study was carried out to map psychosis spectrum disorder risk factors.

Our goal was to find what kind of instrumental methods may help to detect latent liabilities for schizophrenia and bipolar affective disorder

Using online questionnaires n=710 students were screened. Groups were formed based on the inclusion criteria: N = 25 people prone to mood swings, N = 30 people prone to odd experiences and delusive thinking, and a normal control group with N = 30 people. Personality, temperament, self-experiences, affectivity scales, and cognitive screening were conducted in addition to actigraphy coupled with a mobile application for detecting subjective experiences (EMA). Furthermore, instrumental examination of self-agency, testing time interval discrimination and (re)production, eye-tracking, EEG-microstates, and laboratory testing of inflammatory, immunologic and cardio-metabolic measures of allostatic load were applied.

Self-experience disorders: both risk groups showed significantly higher scores than the control group (CG). Self-agency: based on incorrectly attributed responses, the positive schizotypy risk factor (PSF) group differed from the CG (p = 0.003). Antisaccade study: the PSF group showed a difference from the CG (p = 0.002). Actigraphy: based on the distributions of diurnal cumulative activities, it distinguished those with a cyclothymic risk factor (CTF) from the CG (67% probability in the k-means clustering procedure).

Healthy students with a latent liability for schizotypy or bipolarity could be distinguished by some targeted laboratory methods. Susceptibility for bipolarity was indicated by actigraphic analyzes, and the risk for schizotypal development was indicated by deficiencies in the self-agency experience and by anti-saccadic eye movement disorders.

No significant relationships.

First rank symptoms (FRS) of schizophrenia have been used for decades for diagnostic purposes. In the new version of the DSM-5, the American Psychiatric Association (APA) has abolished any further reference to FRS of schizophrenia and treats them like any other “criterion A” symptom (e.g. any kind of hallucination or delusion) with regard to their diagnostic implication. The ICD-10 is currently under revision and may follow suit. In this review, we discuss central points of criticism that are directed against the continuous use of first rank symptoms (FRS) to diagnose schizophrenia.

We describe the specific circumstances in which Schneider articulated his approach to schizophrenia diagnosis and discuss the relevance of his approach today. Further, we discuss anthropological and phenomenological aspects of FRS and highlight the importance of self-disorder (as part of FRS) for the diagnosis of schizophrenia. Finally, we will conclude by suggesting that the theory and rationale behind the definition of FRS is still important for psychopathological as well as neurobiological approaches today.

Results of a pivotal meta-analysis and other studies show relatively poor sensitivity, yet relatively high specificity for FRS as diagnostic marker for schizophrenia. Several methodological issues impede a systematic assessment of the usefulness of FRS in the diagnosis of schizophrenia. However, there is good evidence that FRS may still be useful to differentiate schizophrenia from somatic causes of psychotic states. This may be particularly important in countries or situations with little access to other diagnostic tests. FRS may thus still represent a useful aid for clinicians in the diagnostic process.

In conclusion, we suggest to continue a tradition of careful clinical observation and fine-grained psychopathological assessment, including a focus on symptoms regarding self-disorders, which reflects a key aspect of psychosis. We suggest that the importance of FRS may indeed be scaled down to a degree that the occurrence of a single FRS alone should not suffice to diagnose schizophrenia, but, on the other hand, absence of FRS should be regarded as a warning sign that the diagnosis of schizophrenia or schizoaffective disorder is not warranted and requires specific care to rule out other causes, particularly neurological and other somatic disorders. With respect to the current stage of the development of ICD-11, we appreciate the fact that self-disorders are explicitly mentioned (and distinguished from delusions) in the list of mandatory symptoms but still feel that delusional perceptions and complex hallucinations as defined by Schneider should be distinguished from delusions or hallucinations of “any kind”. Finally, we encourage future research to explore the psychopathological context and the neurobiological correlates of self-disorders as a potential phenotypic trait marker of schizophrenia.