The Self-Report Symptom Inventory (SRSI): a New Instrument for the Assessment of Distorted Symptom Endorsement

Self-report instruments to detect distorted symptom reporting play a crucial role in clinical and forensic psychology. Most of the instruments currently available for this purpose only list implausible symptoms, which makes them easily identifiable as symptom validity tests. We developed the Self-Report Symptom Inventory (SRSI), combining five self-report scales of genuine symptoms with five pseudosymptom scales to screen for distorted symptom reporting in various domains (e.g., depression, post-traumatic stress). With a preliminary questionnaire version, we collected data in a heterogeneous sample (N = 239) and performed an item selection, resulting in the final 107-item version. This version was evaluated in civil forensic patients, inmates of a prison, and a population-based sample; N = 387). Data show that (a) SRSI pseudosymptom scores correlate highly (=. 80) with other instruments tapping distorted symptom endorsement, notably the Structured Inventory of Malingered Symptomatology; (b) High SRSI pseudosymptom scores tend to correlate with underperformance; and (c) The psychometric features of the SRSI are satisfactory, with internal consistency for the total scales >.90 and retest reliability >.85. The instrument appears to be a promising tool for examining symptom exaggeration, but further work is required, in particular cross-validation with other samples and different methods.