The validity and reliability of the Italian version of the Hypomanic Personality Scale (I-HPS)

Objectives: To validate the Italian version of the Hypomanic Personality Scale (I-HPS) in a non-clinical sample of young adults. Materials and Methods: Reliability, convergent and divergent validity, and discriminant capacity of the Italian I-HPS were explored in a sample including 456 undergraduate students attending an Italian university (males: n = 210 [46%]). Convergent and divergent validity was tested by association with the Marlowe-Crowne Social Desirability Scale (SDS); the short Temperament Evaluation of Memphis, Pisa, Paris and San Diego - Autoquestionnaire (TEMPS-A); the 12-item General Health Questionnaire (GHQ-12); the Peters et al. Delusions Inventory (PDI); and the extended Launay-Slade Hallucination Scale (E-LSHS). Discriminant capacity of the I-HPS was tested by Latent Class Analysis (LCA). Results: Reliability of the I-HPS, as measured with the ordinal Cronbach's alpha, was 0.91. There were no differences in the distribution of I-HPS scores by gender, or parental education, our proxy for socio-economic status. Age was negatively related to I-HPS scores (Pearson's r = -0.15, p = 0.002). Scores on I-HPS were negatively related to social desirability (r = -0.23). As expected, the I-HPS was related to TEMPS-A subscales measuring hypomania-proneness more than to TEMPS-A subscales measuring proneness to depression or anxiety (Steigers' z test p < 0.001 or lower). The I-HPS revealed a stronger association with measures of delusion-(PDI) and hallucination-proneness (E-LSHS) than with generalist psychological distress (GHQ-12): Steigers' z test p < 0.0001 in all comparisons. In the sample, 45 (10%) scored ≥ 6 on the GHQ-12 and ≥ 8 on the PDI, our psychometric threshold for higher risk of psychosis. LCA identified three classes in the sample. Compared to the baseline class (42.8% of participants), people at a higher risk of psychosis were more likely to fall in the intermediate class (23.9%), and, with greater odds, in the "high propensity to hypomania" class (33.3%). Conclusions: The I-HPS reveals good psychometric properties in line with the other studies on the cross-cultural validity of the I-HPS as currently tested in German, Spanish, and French samples. The I-HPS is a suitable measure to identify people with hypomanic personality and a promising tool to assist the identification of individuals at a higher risk of bipolar disorder.