The aim of this study was to critically examine the prognostic validity of various clinical high-risk (CHR) criteria alone and in combination with additional clinical characteristics.

A total of 188 CHR positive persons from the region of Zurich, Switzerland (mean age 20.5 years; 60.2% male), meeting ultra high-risk (UHR) and/or basic symptoms (BS) criteria, were followed over three years. The test battery included the Structured Interview for Prodromal Syndromes (SIPS), verbal IQ and many other screening tools. Conversion to psychosis was defined according to ICD-10 criteria for schizophrenia (F20) or brief psychotic disorder (F23).

Altogether n = 24 persons developed manifest psychosis within three years and according to Kaplan–Meier survival analysis, the projected conversion rate was 17.5%. The predictive accuracy of UHR was statistically significant but poor (area under the curve [AUC] = 0.65, P < .05), whereas BS did not predict psychosis beyond mere chance (AUC = 0.52, P = .730). Sensitivity and specificity were 0.83 and 0.47 for UHR, and 0.96 and 0.09 for BS. UHR plus BS achieved an AUC = 0.66, with sensitivity and specificity of 0.75 and 0.56. In comparison, baseline antipsychotic medication yielded a predictive accuracy of AUC = 0.62 (sensitivity = 0.42; specificity = 0.82). A multivariable prediction model comprising continuous measures of positive symptoms and verbal IQ achieved a substantially improved prognostic accuracy (AUC = 0.85; sensitivity = 0.86; specificity = 0.85; positive predictive value = 0.54; negative predictive value = 0.97).

We showed that BS have no predictive accuracy beyond chance, while UHR criteria poorly predict conversion to psychosis. Combining BS with UHR criteria did not improve the predictive accuracy of UHR alone. In contrast, dimensional measures of both positive symptoms and verbal IQ showed excellent prognostic validity. A critical re-thinking of binary at-risk criteria is necessary in order to improve the prognosis of psychotic disorders.

DSM-5 introduced a fundamental revision of the category of somatoform disorders, which resulted in the new somatic symptom disorder (SSD) and related disorders. However, prognostic validity of SSD remains unclear, while other classification proposals, such as bodily distress disorder (BDD) or polysymptomatic distress disorder (PSDD), might be promising alternatives for the new ICD-11. Therefore, the comparison of the different approaches concerning long-term prognosis of disorder-relevant factors is of special interest.

In a longitudinal design (baseline, 1-year, and 4-year follow-up), the three proposals (SSD, BDD, PSDD) were compared in an age-representative sample of the German general population (N = 321). To this end, the baseline sample was divided into three independent pairs of groups (with/without SSD, with/without BDD, with/without PSDD). It was tested how well each approach differentiated with regard to medium- and long-term healthcare utilization, number of symptoms, and impairment.

Criteria for BDD distinguished best with regard to future healthcare utilization resulting in a large-sized effect (f = 0.44) for the difference between persons with and without BDD, while SSD and PSDD revealed only medium-sized effects (f = 0.28 and f = 0.32) between subjects with and without diagnosis. The three proposals distinguished equally well with regard to future subjective impairment (between f = 0.39 and f = 0.41) and the number of reported symptoms (between f = 0.77 and f = 0.83).

In accordance with our data regarding prognostic validity, the current draft of the WHO group is based on the BDD proposal. However, existing limitations and weaknesses of the present proposal for the ICD-11 are further discussed.