Are visual analogue scales valid instruments to measure psychological pain in psychiatric patients?

Objective: The Psychological-Physical-Pain Visual Analogue Scale (PPP-VAS) was thought to probably help in identifying patients at risk of suicide. However, no data on its validity to measure psychological pain was available. Our main aim was to investigate the convergent validity of the PPP-VAS using two well-validated scales of psychological pain, the Orbach and Mikulincer Mental Pain scale (OMMP) and the Holden et al. Psychache Scale. Methods: This multicentre study recruited a total of 1618 adult psychiatric inpatients and outpatients in Italy. Psychological pain was evaluated using the OMMP, Holden et al., and PPP-VAS scales. Psychiatric status, suicidal status, physical pain, depression, and hopelessness were also assessed. Results: A structural equation model (SEM) using the items of psychological pain from the PPP-VAS showed that items loaded significantly on the psychological pain factor and showed good fit. Similarly, a second SEM model using the three scales of psychological pain showed acceptable fit and converged into a psychological pain construct. Correlations between the PPP-VAS and depression, hopelessness, and physical pain showed moderate correlations ( r = 0.43 to r = 0.67). Finally, psychological pain evaluated with the PPP-VAS was significantly related with recent suicidal ideation in all patients (OR [95 % CI] = 1.07 [1.05, 1.09]) and recent suicide attempts in moderately to severely depressed patients, OR [95 % CI] = 1.01 [1.02, 1.03]. Conclusion: The PPP-VAS showed good psychometric properties in evaluating psychological pain. The characteristics of the PPP-VAS makes this scale a great option for its use in clinical practice to detect patients at risk of suicide.