Sanne H. Booij

Background The clinical staging model states that psychosis develops through subsequent stages of illness severity. To better understand what drives illness progression, more extensive comparison across clinical stages is needed. The current paper presents an in‐depth characterization of individuals with different levels of risk for psychosis (i.e., different early clinical stages), using a multimethod approach of cross‐sectional assessments and daily diary reports. Methods Data came from the Mirorr study that includes N = 96 individuals, divided across four subgroups ( n 1 = 25, n 2 = 27, n 3 = 24, and n 4 = 20). These subgroups, each with an increasing risk for psychosis, represent clinical stages 0‐1b. Cross‐sectional data and 90‐day daily diary data on psychopathology, well‐being, psychosocial functioning, risk and protective factors were statistically compared across subgroups (stages) and descriptively compared across domains and assessment methods. Results Psychopathology increased across subgroups, although not always linearly and nuanced differences were seen between assessment methods. Well‐being and functioning differed mostly between subgroup 1 and the other subgroups, suggesting differences between non‐clinical and clinical populations. Risk and protective factors differed mostly between the two highest and lowest subgroups, especially regarding need of social support and coping, suggesting differences between those with and without substantial psychotic experiences. Subgroup 4 (stage 1b) reported especially high levels of daily positive and negative psychotic experiences. Conclusions Risk for psychosis exists in larger contexts of mental health and factors of risk and protection that differ across stages and assessment methods. Taking a broad, multi‐method approach is an important next step to understand the complex development of youth mental health problems.