What is the 'psychosis continuum' and why is it relevant to this research?

The 'psychosis continuum' suggests that psychotic experiences exist on a spectrum, ranging from normal experiences to full-blown psychosis. This concept gained traction because studies indicated the surprising commonality of psychotic symptoms in the general population. This study questions the validity of this concept by revealing the potential for misinterpreting self-reported experiences as indicators of the 'psychosis continuum'.

What methods did the study use to assess psychosis, and how did it work?

The study used a self-rated questionnaire, the PLIKS-LOFUS (adapted from PLIKSI), to assess 'psychosis-like' symptoms in participants. If participants reported at least one 'psychosis-like' experience impacting them or their family, they underwent clinical assessment. This assessment involved nurses with specialized training in psychopathology conducting semi-structured interviews. Each assessment was then discussed with an experienced senior psychiatrist and researcher. The primary goal was to determine if the self-reported symptoms accurately reflected true psychosis.

What were the main findings of the study regarding self-reported questionnaires?

The study's findings revealed a significant discrepancy. Of the 40 participants who reported 'psychosis-like' experiences and underwent clinical assessment, only 7 (17.5%) were diagnosed with a psychotic episode. This means that a large proportion (82.5%) of individuals who reported symptoms on the self-rated questionnaire did not meet the criteria for a clinical diagnosis of psychosis. This high rate of false positives raises serious questions about the reliability of using self-rated questionnaires to identify psychosis in the general population.

What are the implications of these findings for understanding psychosis?

The implications are that relying solely on self-rated questionnaires to assess psychosis may lead to misdiagnosis and inaccurate understanding of the condition. The high rate of false positives suggests that the experiences reported on these questionnaires may not always reflect true psychosis. This calls for caution in interpreting findings related to the 'psychosis continuum' and highlights the need for more reliable methods for assessing psychosis, especially within the general population. The findings also suggest that self-reported experiences may have qualitative differences when compared to clinical diagnoses.

Why does this study question the use of self-rated questionnaires for assessing psychosis?

The study's results challenge the validity of using self-reported questionnaires to identify psychosis, primarily because these questionnaires appear to generate a high rate of false positives. While the questionnaires might identify individuals experiencing unusual thoughts or perceptions, these experiences do not necessarily equate to a clinical diagnosis of psychosis. The study emphasizes the need for more rigorous methods, like clinical assessments, to accurately identify psychosis and understand its prevalence.

Maze of self-reporting with floating question marks representing challenges in psychosis assessment.

Are Self-Rated Psychosis Questionnaires Valid? What Recent Research Reveals

Rhea Morgan in Mind & Education December 2025 • 4 min read.

"A new study casts doubt on the reliability of self-reported psychosis symptoms in the general population, urging caution in interpreting 'psychosis continuum' findings."

For years, studies have suggested that psychotic symptoms are surprisingly common in the general population. This has led to the idea of a 'psychosis continuum,' suggesting that psychosis exists on a spectrum with normal experiences. However, this concept has faced criticism, particularly regarding the methods used to assess psychosis in these studies.

Prevalence rates of psychotic experiences in the general population have been reported around 7.2%, and a WHO survey indicated 5.8%. These assessments often rely on two main methods: structured interviews conducted by lay interviewers or self-rating questionnaires asking about 'psychosis-like symptoms.' Positive responses on these questionnaires are frequently interpreted as indicative of psychosis.

However, some researchers question whether self-reported 'psychosis-like' experiences truly reflect psychosis. Studies have found that these self-reports may not accurately represent attenuated or frank psychosis and that qualitative differences exist between the experiences reported by patients and non-clinical individuals. Furthermore, structured interviews have shown limited utility in detecting psychosis in the general population. This raises a critical question: are self-rated questionnaires a valid way to assess psychosis?

The Study: Self-Reported Symptoms vs. Clinical Assessment

Maze of self-reporting with floating question marks representing challenges in psychosis assessment.

A recent study published in 'Schizophrenia Research' investigated the validity of self-rated questionnaires in identifying psychosis within the general population. The researchers aimed to determine if positive answers on a self-rated questionnaire for 'psychosis-like' symptoms accurately reflect true psychosis.

The study was a cross-sectional interview nested within a larger, ongoing prospective cohort study called the Lolland-Falster Health Study (LOFUS). Data collection included questionnaires, physical examinations, and biological samples. The questionnaire included items assessing psychosis-like symptoms (PLIKS-LOFUS), adapted from a 12-core element screening tool (PLIKSI).

Participants who reported at least one psychosis-like experience and indicated that these experiences had an impact on them or their family were invited for clinical assessment.
Nurses with specialized training in psychopathology conducted semi-structured interviews to assess psychopathology. These nurses had 2-5 years of experience assessing psychosis in individuals seeking early detection services.
All assessments were discussed with an experienced senior psychiatrist and researcher.

Of the 40 participants who underwent clinical assessment, only 7 (17.5%) were found to have had a psychotic episode. Notably, 3 (7.5%) were new cases identified through the study. This means that a significant majority (82.5%) of those who self-reported psychosis-like experiences were, in fact, false positives.

Implications for Understanding Psychosis

This study's findings raise concerns about relying solely on self-rated questionnaires to assess psychosis in the general population. The high rate of false positives suggests a significant disconnect between what people report on questionnaires and what clinicians diagnose as psychosis.

The researchers highlight the importance of considering experiential content, the structure of the experience, and the context in which it occurs when assessing psychosis. Self-rating questionnaires, by their nature, strip away context and focus solely on content, making them inadequate for validly examining psychosis.

These findings have potential implications for the 'psychosis continuum' hypothesis, which relies heavily on studies using self-rating scales. The study underscores the need for caution when interpreting such research and suggests that more rigorous methods, including clinical assessment, are necessary for accurately understanding psychosis in the general population.