The Clinical Outcomes in Measurement-based care Assessment of Symptoms and Severity (COMPASS) Scale (COMPASS)

The COMPASS scale is a psychopathology rating instrument, developed to assess individuals with first episode psychotic disorders in community settings. The COMPASS scale is available in different lengths, derived from the original 12-item version using Mokken scale analysis:

1. 12-Item Version: The original assessment used in the RAISE-ETP study.
2. 10-Item Version: This version was derived by removing two items—Elevated/Expansive Mood and Impulsive Behavior—due to their low statistical scalability coefficients in the RAISE-ETP data.
3. 5-Item Version: A shorter version focused solely on positive and negative symptoms (Unusual Thought Content, Hallucinations, Conceptual Disorganization, Apathy, and Asociality) was also derived and met unidimensionality criteria. This version is considered useful in settings where minimizing assessment time is the primary concern.

Each COMPASS item is rated on a 7-point severity scale, ranging from 0 (symptom not present) to 6 (very severe).

Suggested in the original paper to use the time-frame ‘since the last treatment visit’.

• Robinson, D. G., John, M., Miller, A. L., Schooler, N. R., & Kane, J. M. (2024). The COMPASS scale for the assessment of individuals with first episode psychotic disorders. Schizophrenia research, 274, 307–314. https://www.sciencedirect.com/science/article/pii/S0920996424004511?via=ihub

• The scale has item definitions, suggested probe questions for each item and descriptions of each severity level. There are no specific training materials.

• As summarised from development paper: The preferred 10-item version demonstrated improved unidimensionality (high scalability coefficients, H>0.3) and successfully met the requirement for monotonicity, indicating it is statistically robust for ordering patients based on their sum scores. Furthermore, items assessing core psychotic symptoms (e.g., Suspiciousness, Hallucinations, Unusual Thought Content) showed high test-retest reliability (correlations >0.7). This information was based on data collected from community clinics, in first-episode psychosis patients in the US.

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• The items used in the original 12-item COMPASS scale were directly sourced from existing, established instruments for assessing psychosis symptoms: 4-Item Positive Symptom Rating Scale & 5-Dimensional Scale to Evaluate Psychopathology in Schizophrenia (5-STEPS).