Psychometric study of the revised Mood Rhythm Instrument (MRhI-r) in major depressive disorder.

Major depressive disorder (MDD) affects over 300 million people globally. The etiology of MDD is linked to circadian rhythm disruption, including the diurnal pattern of mood, cognition, and physiological processes. The revised Mood Rhythm Instrument (MRhI-r) was developed to assess self-perceived rhythmicity of symptoms and has previously been tested in nonclinical populations. This study evaluates the psychometric properties of the MRhI-r in a clinical MDD sample. Individuals with MDD and healthy controls completed the MRhI-r at baseline and after 2 weeks. Psychometric properties were assessed using confirmatory factor analysis (CFA) of factor structures previously determined in a nonclinical sample, item response theory (IRT), receiver operating characteristic (ROC) curves, internal consistency, and test-retest reliability. Sex differences in symptom peak frequency and timing were assessed within the MDD group. The sample included 102 MDD participants (65% female, ages 17-70, M ± SD = 37 ± 14) and 94 healthy controls (67% female, ages 18-72, M ± SD = 37 ± 15). CFA showed excellent model fit and IRT analysis indicated good item fit. ROC analysis showed a diagnostic threshold of 2.5 with 64% sensitivity and 72% specificity. The MRhI-r scores demonstrated good internal consistency (α = .78, ω = .82) and moderate test-retest reliability (r = 0.69). No sex differences were found in peak frequency or timing within the MDD group. The psychometric properties of the MRhI-r in individuals with MDD support the three-factor model seen in previous studies. This study assesses the psychometric properties of the MRhI-r in a clinical sample, endorsing its use for evaluating symptom rhythmicity in clinically depressed individuals. (PsycInfo Database Record (c) 2025 APA, all rights reserved).