The Concept of Psychological Distress and Its Assessment: A Clinimetric Analysis of the SCL-90-R

Many studies have been conducted on psychological distress but the question of how to conceptualize and assess this phenomenon still remains a controversial issue. Clinimetrics, the science of clinical measurements, may pave the ground for a substantial revision of the clinical conceptualization and assessment of this construct. A Rasch analysis was performed to evaluate whether the Symptom Checklist-90-Revised (SCL-90-R) and its subscales were valid indices of underlying dimensions of psychological distress. Based on the clinimetric validation of the SCL-90-R, as well as on a critical review of the available literature, a concept analysis of psychological distress was performed. The SCL-90-R total score misfitted the Rasch model but it was found to have a Person Separation Reliability Index of 0.94. Model fit was achieved after the exclusion of six misfitting items. Paired t tests indicated that all the subscales of the SCL-90-R were unidimensional. Psychological distress was defined as a subjective, unifying, dimensional, and transdiagnostic construct consisting in a unique experience of discomfort, which may involve a sense of demoralization, the experience of feeling broken or mental pain, a sense of anguish, symptoms of somatization and attention deficit hyperactivity disorder (ADHD), feelings of anger, self-perceived lack of control, and self-criticism. Our findings also showed that the SCL-90-R could reliably differentiate healthy stress from psychological distress, and identify individuals at risk of psychiatric disorders. The total score of the 84-item version of the SCL-90-R may be used as an overall indicator of psychological distress. The subscales are recommended to assess the severity of specific symptomatic manifestations of psychological distress.