Description

The Symptom Checklist-90 (SCL-90) is a psychometric tool designed to assess psychological distress and psychopathological symptoms. The SCL-90 was developed by Leonard R. Derogatis, Nick Melisaratos, and their colleagues, and it consists of 90 items that evaluate a wide range of psychological problems and symptoms.

Purpose

The main purpose of the SCL-90 is to provide an overall assessment of an individual’s psychological distress and to identify the presence of specific psychopathological symptoms. This tool is widely used in clinical assessments, research studies, and therapeutic interventions to aid in diagnosis and in monitoring treatment progress.

Analysis

The SCL-90 includes 90 items that cover nine primary dimensions of psychological symptoms:
Somatization: Refers to physical symptoms caused by psychological factors.
Obsessive-Compulsive: Refers to repetitive thoughts and compulsive behaviors.
Interpersonal Sensitivity: Refers to feelings of inadequacy and difficulties in interpersonal relationships.
Depression: Refers to feelings of sadness, hopelessness, and lack of interest.
Anxiety: Refers to feelings of worry and fear.
Hostility: Refers to feelings of anger and aggressiveness.
Phobic Anxiety: Refers to intense and irrational fears.
Paranoid Ideation: Refers to suspicious and persecutory thoughts.
Psychoticism: Refers to disorganized thinking and perceptions.
Participants are asked to rate the degree to which they experienced each symptom during the past seven days using a five-point Likert scale ranging from “not at all” (0) to “extremely” (4).

Scoring

Scoring of the SCL-90 is based on the sum of scores for each of the nine dimensions, as well as a total score called the Global Severity Index (GSI). The GSI provides an overall measure of psychological distress and is used to compare symptom intensity between different individuals or groups.
Two additional commonly used indices are:
Positive Symptom Total (PST): The total number of symptoms reported by the individual.
Positive Symptom Distress Index (PSDI): An index of the intensity of the symptoms reported by the individual.

References

Derogatis, L. R., Lipman, R. S., & Covi, L. (1973). SCL-90: An outpatient psychiatric rating scale—preliminary report. Psychopharmacology Bulletin, 9(1), 13–28.
Derogatis, L. R. (1994). SCL-90-R: Symptom Checklist-90-R: Administration, scoring, and procedures manual. NCS Pearson.
Holi, M. M. (2003). Assessment of psychiatric symptoms using the SCL-90. University of Helsinki.
Prinz, U., Nutzinger, D. O., Schulz, H., Petermann, F., Braukhaus, C., & Andreas, S. (2013). Comparative psychometric analyses of the SCL-90-R and its short versions in patients with affective disorders. BMC Psychiatry, 13, 104.