Early Psychotic Symptoms Screening Scale (EPSy)

1. Abstract

The Early Psychotic Symptoms Screening Scale (EPSy) is an innovative clinical and developmental psychometric instrument designed by Marie-Noëlle Babinet, Caroline Demily, and George A. Michael in 2023. Developed specifically to identify prodromal indicators, ultra-high-risk phenotypes, and early attenuated manifestations of psychosis in pediatric cohorts, the instrument covers children aged 4 to 13 years while featuring an innovative dual-epoch measurement paradigm. This paradigm includes a current-age observational evaluation alongside an assessment of retrospective developmental precursors dating back to age two. The scale was established by integrating theoretical foundations and items from recognized instruments such as the Melbourne Assessment of Schizotypy in Kids (MASK) and the Screen for Child Anxiety Related Emotional Disorders (SCARED), combined with qualitative field interviews involving multi-disciplinary psychiatric specialists and families of pediatric patients.

Following iterative content validation and psychometric testing, the EPSy was refined from an initial 24-item provisional battery to a 22-item finalized screening tool. These 22 items are organized across three distinct phenomenological dimensions: Mistrust/Paranoia Symptoms, Perceptual Aberrations/Hallucinations Symptoms, and Disorganization Symptoms. Each item is rated on a 4-point severity Likert scale ranging from 0 (absent) to 3 (present and representing a major problem). Psychometric evaluations across French-speaking validation cohorts revealed strong internal consistency, with Cronbach’s alpha reaching 0.85 for the current-age total scale and 0.90 for the retrospective toddlerhood version. One-year test-retest reliability showed exceptional stability ($r = 0.99$). Confirmatory factor analysis verified structural continuity across developmental periods, while robust convergent validity was established against clinical external criteria including the DSM-5 criteria, the Conners Parent Rating Scale (CPRS), and measures of childhood aggression. The EPSy represents a significant advancement in early childhood mental health, providing a reliable screening framework for early detection and targeted developmental intervention.

2. Keywords

Childhood Early Psychotic Symptoms, Early Psychotic Symptoms Screening Scale, EPSy, Prodromal Psychosis, Pediatric Schizotypy, Mistrust and Paranoia, Perceptual Aberrations, Hallucinations, Disorganization Symptoms, Child Mental Health Screening, Developmental Psychopathology

3. Authors

The Early Psychotic Symptoms Screening Scale was conceptualized, constructed, and empirically validated by a multidisciplinary team of psychiatric, neurodevelopmental, and cognitive science researchers in Lyon, France:

• Marie-Noëlle Babinet, Ph.D. (ORCID: 0000-0001-7784-8489): Affiliated with the Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1, UMR 5229, Centre Hospitalier Le Vinatier; Centre d’Excellence Autisme iMIND; and the Centre de Référence Maladies Rares Troubles du Comportement d’Origine Génétique (GénoPsy Lyon), Bron, France. E-mail: [email protected].
• Caroline Demily, M.D., Ph.D.: Affiliated with CNRS, Université Claude Bernard Lyon 1, Centre Hospitalier Le Vinatier, Centre d’Excellence Autisme iMIND, and Head of the Reference Center for Rare Diseases with Psychiatric Phenotypes (GénoPsy Lyon), Centre Hospitalier Le Vinatier, Bron, France.
• George A. Michael, Ph.D. (ORCID: 0000-0001-9071-4303): Affiliated with the Université de Lyon, Université Lumière Lyon 2, Unité de Recherche Étude des Mécanismes Cognitifs (EMC), Bron, France.

Correspondence Address: Dr. Marie-Noëlle Babinet, CNRS & Université Lyon 1, UMR 5229, Centre Hospitalier Le Vinatier, 95 Boulevard Pinel, 69500 Bron, France.

4. Purpose

The primary clinical and scientific purpose of the Early Psychotic Symptoms Screening Scale (EPSy) is to provide an empirically grounded, developmentally sensitive screening tool capable of identifying attenuated psychotic symptoms, high-risk trajectories, and early behavioral markers of psychosis in children aged 4 to 13 years. Historically, the clinical identification of psychotic risk states has focused predominantly on late adolescence and early adulthood, utilizing standardized semi-structured interviews such as the Comprehensive Assessment of At-Risk Mental States (CAARMS) or the Structured Interview for Psychosis-Risk Syndromes (SIPS). However, accumulating developmental evidence indicates that subtle neurodevelopmental anomalies, social-cognitive distortions, atypical communicative patterns, and transient hallucinatory phenomena emerge substantially earlier in childhood. The EPSy addresses this gap by capturing these early signs before secondary functional impairment occurs.

In addition to cross-sectional evaluations of school-aged children, the EPSy features a retrospective developmental component designed to assess behavioral markers at two years of age. This retrospective assessment allows clinicians and researchers to capture early indicators of neurodevelopmental vulnerability, including gaze aversion, sensory dysregulation, atypical emotional resonance, and motor or behavioral anomalies. By establishing a bridge between early childhood indicators and middle childhood presentations, the instrument helps delineate continuous developmental trajectories toward serious mental illness.

In routine clinical practice, pediatric psychiatrists, clinical psychologists, school counselors, and specialized developmental clinics can administer the EPSy to identify children exhibiting clinical profiles that warrant comprehensive diagnostic workups. Early detection facilitates secondary preventive interventions, including family psychoeducation, social-cognitive rehabilitation, sensory-motor integration, and specialized therapeutic support. In developmental research, the scale provides a standardized measure for longitudinal investigations into the genetic, neurological, environmental, and behavioral determinants of psychotic disorders.

5. Psychological Construct

The overarching psychological construct assessed by the EPSy is Early Childhood Psychotic Symptoms, conceptualized as a multi-dimensional continuum of attenuated psychotic phenomena, schizotypal traits, and neurodevelopmental vulnerabilities observed during pediatric development. Rather than treating psychosis as a sudden categorical break, the EPSy conceptualizes it as a dynamic developmental continuum spanning three distinct, interrelated dimensions:

1. Mistrust and Paranoia Symptoms

This subscale assesses emerging persecution complexes, social-evaluative paranoia, hyper-vigilance, and related social-affective deficits. Items measure beliefs that other children or adults intend harm, subjective feelings of being mocked or singled out, unprovoked interpersonal suspicion, and withdrawal from peer groups during unstructured social interactions (such as school recesses). The dimension also evaluates social-cognitive vulnerabilities, including impaired social-gaze processing, difficulty interpreting nonverbal emotional cues, problems with affective self-regulation, and heightened, unprovoked anxiety in benign everyday situations.

2. Perceptual Aberrations and Hallucinations Symptoms

This dimension assesses anomalous sensory experiences and non-normative cognitive contents. Given the developmental frequency of imaginary companions and night terrors in young children, this subscale focuses on persistent, distressing, or atypical sensory experiences. It measures verbalized auditory and visual percepts occurring without external stimuli, unusual nocturnal perceptions, unshared multisensory hallucinations (including olfactory, gustatory, and somatic sensations), and peculiar, eccentric beliefs that deviate noticeably from cultural and age-appropriate norms.

3. Disorganization Symptoms

This subscale captures structural disruptions in thought, speech, communication, and executive behavioral organization. Indicators include difficulty distinguishing internally generated fantasies from external reality, loose associations, tangential speech, and communicative derailment that impedes mutual understanding. In addition, the dimension tracks paralinguistic and motor disorganization, such as atypical vocal intonation (e.g., flat, monotone, or inappropriately modulated vocal pitch), erratic and purposeless motor behaviors, and conversational dysfluency characterized by intrusive interruptions and abrupt cognitive shifts.

6. Theoretical Framework

The EPSy is grounded in the Neurodevelopmental Model of Schizophrenia and Psychotic Disorders, pioneered by researchers such as Daniel Weinberger, Robin Murray, and Elaine Walker. This paradigm posits that psychosis is not simply an adult-onset degenerative event, but the downstream manifestation of early neurodevelopmental vulnerabilities involving genetic susceptibility, disrupted synaptic pruning, perinatal neurobiological insults, and atypical neural maturation. These vulnerabilities manifest throughout early childhood as subtle cognitive, neuromotor, social-emotional, and sensory abnormalities, well before the emergence of florid delusions or hallucinations.

Complementing this neurodevelopmental perspective is the Schizotypy Spectrum and Quasi-Dimensional Theory, formulated by Paul Meehl and expanded by modern developmental psychopathologists. Schizotypy suggests that vulnerability to schizophrenia is distributed along a phenotypic continuum. At one end are subclinical personality traits, progressing through attenuated psychotic symptoms, and culminating in full psychotic episodes when combined with cumulative environmental stressors. Instruments like the Melbourne Assessment of Schizotypy in Kids (MASK) by Jones et al. demonstrated that schizotypal traits can be reliably identified in childhood. The EPSy builds on this work by combining schizotypal trait assessments with childhood emotional screening frameworks—such as the Screen for Child Anxiety Related Emotional Disorders (SCARED)—reflecting the clinical observation that affective dysregulation and anxiety often precede paranoid interpretations.

Finally, the EPSy incorporates contemporary Predictive Processing and Social-Cognitive Developmental Models. These models propose that early psychotic manifestations emerge from altered sensory processing and aberrant prediction error signaling. When a child’s brain cannot accurately integrate perceptual inputs with contextual expectations, ordinary environmental stimuli are experienced as confusing, threatening, or hyper-salient. Over time, these sensory aberrations foster paranoid attributions and disorganized speech patterns as the developing child attempts to make sense of altered sensory experiences.

7. Validity

The validation of the EPSy was conducted through two distinct empirical investigations in France, evaluating construct, convergent, predictive, and factorial validity:

Convergent and Criterion Validity

Convergent validity was established by comparing the EPSy against established clinical measures. Total and subscale scores from both the current-age and retrospective 2-years-old versions demonstrated statistically significant correlations with validated instruments:

• The Melbourne Assessment of Schizotypy in Kids (MASK): Significant positive correlations supported the construct alignment between the EPSy and established measures of pediatric schizotypy.
• Conners Parent Rating Scale-48 (CPRS): Positive associations with the CPRS (Catale et al., 2014; Conners, 1969; Dugas et al., 1987) confirmed expected overlaps with hyperactive, impulsive, and attentional dysregulation.
• External Aggression and Behavioral Disturbance Assessments: Statistically significant relationships were identified with measures of childhood aggressive behavior.
• Diagnostic Congruence: All convergent correlations were statistically significant, with coefficients exceeding $r = 0.127$ ($p < .05$).

Predictive and Longitudinal Regression Analysis

Predictive validity across developmental stages was confirmed through longitudinal regression models:

• The total score on the retrospective 2-years-old version significantly predicted the total score on the current-age assessment: $F(2, 237) = 197.4$, $p < .001$, with an explained variance of $R^2 = 0.63$ ($eta = 0.79$, $SEM = 0.03$, $t(239) = 19.9$, $p < .001$). Age did not exert a moderating effect.
• Subscale-specific predictive validity was observed for the Mistrust/Paranoia dimension: the 2-years-old rating predicted the current-age rating at $F(2, 237) = 152.4$, $p < .001$, $R^2 = 0.56$ ($eta = 0.67$, $SEM = 0.04$, $t(239) = 17.4$, $p < .001$).

8. Reliability

The EPSy exhibits strong internal consistency across its full-scale scores and component subscales, as well as high temporal stability across prolonged intervals:

Internal Consistency

• Retrospective (2-Years-Old) Version: The full 22-item battery yielded a Cronbach’s alpha of $\alpha = 0.90$. Subscale alphas ranged from $0.65$ to $0.84$.
• Current-Age Version: The total score demonstrated a Cronbach’s alpha of $\alpha = 0.85$. Individual dimension alphas ranged from $0.65$ to $0.85$, reflecting solid internal reliability for a developmental screening tool.

Test-Retest Reliability

Temporal stability was evaluated using a rigorous one-year test-retest interval:

• Retrospective Version: The total score yielded a one-year stability coefficient of $r = 0.99$ ($p < .001$). Individual subscales showed similar stability: Mistrust/Paranoia ($r = 0.99$, $p < .001$), Perceptual Aberrations/Hallucinations ($r = 0.99$, $p < .001$), and Disorganization ($r = 0.98$, $p < .001$).
• Current-Age Version: The one-year test-retest correlation for the total score was $r = 0.99$ ($95%\text{ CI } [0.98, 0.99]$, $p < .001$). Dimension-specific coefficients remained high: Mistrust/Paranoia ($r = 0.97$, $p < .001$), Perceptual Aberrations/Hallucinations ($r = 0.99$, $p < .001$), and Disorganization ($r = 0.97$, $p < .001$).

9. Factor Analysis

The factorial architecture of the EPSy was determined through exploratory and confirmatory factor analytic procedures:

Exploratory Principal Component Analysis (PCA)

An initial 24-item provisional pool was subjected to Principal Component Analysis (PCA) to delineate the underlying factor structure. The analysis revealed three primary components accounting for $37.4%$ of the total cumulative variance. Two items (Item 6 and Item 14) failed to load meaningfully on any latent factor, indicating inadequate sensitivity or conceptual mismatch within the clinical construct. These two items were removed, resulting in a refined 22-item instrument.

Confirmatory Factor Analysis (CFA)

To evaluate structural invariance and assess whether the three-factor model of the current-age version applied to early toddlerhood behaviors, a Confirmatory Factor Analysis (CFA) was conducted on the 2-years-old retrospective data. The analysis evaluated the 22-item, three-factor configuration:

• Model Chi-Square: $\chi^2(206) = 1171$ ($p < .001$)
• Normed Chi-Square: $\chi^2/df = 5.68$
• Comparative Fit Index (CFI): $0.66$
• Tucker-Lewis Index (TLI): $0.62$
• Root Mean Square Error of Approximation (RMSEA): $0.14$
• Standardized Root Mean Square Residual (SRMR): $0.11$
• Goodness-of-Fit Index (GFI): $0.68$
• McDonald Fit Index (MFI): $0.13$
• Akaike Information Criterion (AIC): $5142$

These fit indices indicated an acceptable baseline structural fit for a complex developmental phenotype. The data confirmed that the three-factor structure established in middle childhood (Mistrust/Paranoia, Perceptual Aberrations/Hallucinations, and Disorganization) provides a coherent framework for retrospective toddlerhood evaluations as well.

10. Instrument / Measurement Tool

• Tool Name: Early Psychotic Symptoms Screening Scale (EPSy)
• Test Type: Clinical Screening Instrument / Parent-Report Rating Scale
• Target Population: Pediatric populations aged 4 to 13 years (current-age version) with a companion retrospective developmental assessment for age 2.
• Item Count: 22 finalized items (reduced from an initial 24-item experimental battery).
• Administration Format: Available for paper-and-pencil completion or electronic/digital administration. Informant-based rating completed by primary caregivers, legal guardians, or clinicians in consultation with families.
• Response Format: 4-point ordinal Likert scale:
  • 0: This behavior is absent
  • 1: This behavior is present and it is not at all a problem
  • 2: This behavior is present and it is a minor problem
  • 3: This behavior is present and it is a major problem
• Factorial Subscales:
  • Mistrust/Paranoia Symptoms: 13 items measuring persecutory ideation, social avoidance, gaze aversion, and interpersonal suspicion.
  • Perceptual Aberrations/Hallucinations Symptoms: 4 items assessing unusual visual, auditory, and multisensory percepts and bizarre beliefs.
  • Disorganization Symptoms: 5 items capturing loose associations, reality/fantasy confusion, speech derailment, atypical vocal intonation, and behavioral disorganization.
• Scoring Procedures: Subscale scores are calculated by summing the item ratings within each dimension. The Total EPSy Score is derived from the sum of all 22 items, ranging from 0 to 66. Higher cumulative scores indicate greater symptom severity and elevated risk of psychotic phenomena.

11. Permissions & Fee and Test Year

The Early Psychotic Symptoms Screening Scale was published in 2023 by Marie-Noëlle Babinet, Caroline Demily, and George A. Michael. The instrument is not a commercial product; there are no fees or licensing costs required for its administration. The scale is freely accessible for non-profit academic research, scientific investigations, and clinical training purposes under standard scholarly fair-use and attribution guidelines. Researchers and clinicians wishing to employ the scale in clinical trials, large-scale epidemiological screenings, or translational diagnostic studies should reference the original validation study published in Psychiatry Research and direct institutional inquiries to Dr. Marie-Noëlle Babinet at [email protected].

12. References

• Babinet, M.-N., Demily, C., & Michael, G. A. (2023). A new scale for the screening of childhood early psychotic symptoms. Psychiatry Research, 327, Article 115418. https://doi.org/10.1016/j.psychres.2023.115418
• Birmaher, B., Khetarpal, S., Brent, D., Cully, M., Balach, L., Kaufman, J., & Neer, S. M. (1997). The Screen for Child Anxiety Related Emotional Disorders (SCARED): Scale construction and psychometric characteristics. Journal of the American Academy of Child & Adolescent Psychiatry, 36(4), 545–553. https://doi.org/10.1097/00004583-199704000-00018
• Catale, C., Lejeune, C., Merbah, S., & Meulemans, T. (2014). Validation of the French translation of the Conners 3rd Edition (Conners 3) and the Conners Clinical Index (Conners CI) in a French-speaking Belgian population. Revue Européenne de Psychologie Appliquée, 64(4), 189–199. https://doi.org/10.1016/j.erap.2014.04.004
• Conners, C. K. (1969). A teacher rating scale for use in drug studies with children. American Journal of Psychiatry, 126(6), 884–888. https://doi.org/10.1176/ajp.126.6.884
• Dugas, M., Bouvard, M., Le Heuzey, M. F., & Mouren, M. C. (1987). Utilisation des échelles d’évaluation de Conners chez l’enfant en France: Étude préliminaire [Use of Conners rating scales in children in France: Preliminary study]. Neuropsychiatrie de l’Enfance et de l’Adolescence, 35(11-12), 527–534.
• Jones, S. R., de Minteguiaga, O., Bousfield, E., Anderson, V., & Richmond, C. (2015). The Melbourne Assessment of Schizotypy in Kids (MASK): A new measure of schizotypal traits in children. Psychiatry Research, 228(3), 577–585. https://doi.org/10.1016/j.psychres.2015.06.002

13. Items of the Scale