Psychometric Validation of the Purpose in Life Test-Short Form (PIL-SF) in Individuals Diagnosed with Severe Mental Illness

Abstract

Background: Meaning in Life (MiL) represents a key variable in mental health models of personal recovery. There is a need for straightforward and concise instruments to assess this construct quantitatively in individuals diagnosed with severe mental illness (SMI). Objective: The aim of the present study was to test the psychometric properties of the Purpose in Life Test-Short Form (PIL-SF), a brief self-report measuring the presence of MiL, in a sample of individuals with SMI. Methods: The participants were 41 adults (21 women, 51.8% and 20 men, 48.2%) aged 18 to 65 years (M = 50.05; SD = 10.73) with a diagnosis of SMI (schizophrenia, 61%; bipolar disorder, 26.8%; borderline personality disorder, 7.3%; and major depression, 4.9%) and clinically stable. The PIL-SF, Satisfaction with Life Scale (SWLS), Oxford Happiness Questionnaire—6 Item (OHQ-6), Engagement in Meaningful Activities Survey (EMAS), and Seeking of Noetic Goals—8 Item (SONG-8) were used. Descriptive analysis, estimation of the internal consistency, and Confirmatory Factor Analysis of the PIL-SF were conducted. Furthermore, correlations between the PIL-SF, SWLS, OHQ-6, EMAS, and SONG-8 were calculated. Results: The PIL-SF showed acceptable internal consistency (ω = 0.81) and an excellent fit as a unidimensional scale (CFI = 1.000, TLI = 1.070, RMSEA = 0.000, SRMR = 0.021), confirming its factorial structure. Regarding construct validity, correlations between the PIL-SF and the SWLS (ρ = 0.54, p < 0.001), the OHQ-6 (ρ = 0.52, p < 0.001), and EMAS (ρ = 0.44, p < 0.005) were positive and significant, whereas the correlations between the PIL-SF and the SONG-8NfM (ρ = −0.35, p < 0.025) were negative and significant. Conclusions: The Spanish version of the PIL-SF appears to be a reliable and valid instrument to measure the presence of MiL in adults with SMI.