Unhappy While Depressed: Examining the Dimensionality, Reliability and Validity of the Subjective Happiness Scale in a Spanish Sample of Patients with Depressive Disorders.

Despite the considerable amount of research evidence on the significant role of subjective happiness on mental health, there is no psychometric study of the Subjective Happiness Scale (SHS) in psychiatric samples. This study was aimed at exploring the psychometric properties of the SHS in a Spanish sample of patients with depressive disorders. Participants were 174 patients with a depressive disorder (70% diagnosed as major depressive disorder) who completed the SHS, the Quick Inventory of Depressive Symptomatology-Self Report (QIDS-SR16), and the EQ-5D Visual Analogue Scale (EQ-5D VAS). Depressive symptoms were also assessed by means of the 17-item Hamilton Depression Rating Scale (HDRS17) and the Clinical Global Impression-Severity (CGI-S) Scale. Dimensionality, internal consistency reliability, construct validity, and responsiveness to change of the SHS were examined. Confirmatory factor analysis replicated the original one-factor structure of the scale. The SHS exhibited good-to-excellent results for internal consistency (α = 0.83) and for convergent [EQ-5D VAS (r = 0.71)] and divergent [QIDS-SR16 (r = -0.72), HDRS17 (r = -0.60) and CGI-S (r = -0.61)] construct validity. The ability of the SHS to differentiate between depression severity levels as well as its responsiveness to clinical change were both highly satisfactory (p < 0.001 in both cases). The SHS retained the soundness of psychometric properties showed in non-clinical samples in a sample of patients with depressive disorders, which supports its use as a reliable and valid outcome measure in the treatment of such disorders.