Melissa Alves Braga de Oliveira

The Mood Rhythm Instrument: development and preliminary report

Objective: To describe the initial steps in the development and validation of a new self-reported instrument designed to assess daily rhythms of mood symptoms, namely, the Mood Rhythm Instrument. Methods: A multidisciplinary group of experts took part in systematic meetings to plan the construction of the instrument. Clarity of items, their relevance to evaluation of mood states, and the consistency of findings in relation to the available evidence on the biological basis of mood disorders were investigated. The internal consistency of the questionnaire was evaluated through Cronbach’s alpha. Results: All of the items proposed in a first version were well rated in terms of clarity. The items more frequently rated as “rhythmic” were related to the somatic symptoms of mood. Their peaks in 24 hours were more frequent in the morning. The items associated with affective symptoms of mood were rated as less rhythmic, and their peak in 24 hours occurred more frequently in the afternoon and evening. Males and females behaved more similarly with respect to somatic than behavioral-affective items. The second version of the Mood Rhythm Instrument had a Cronbach’s alpha of 0.73. Conclusion: The proposed Mood Rhythm Instrument may be able to detect individual rhythms of cognitive and behavioral measures associated with mood states. Validation in larger samples and against objective measures of rhythms, such as actigraphy, is warranted.

Spanish translation of the mood rhythm instrument: a novel approach to mood evaluation

Introduction: The Mood Rhythm Instrument (MRI) is a questionnaire developed to assess the circadian rhythm of mood-related behaviors. The aim of this study was to translate this instrument from Brazilian Portuguese into Spanish. Methods: The translation process consisted of forward translation, adjustment, back translation, back translation review and harmonization. Results: Comparing the initial Spanish translation and the final Spanish version, there were no semantic differences and the items were not changed. Conclusions: The Spanish version of the MRI is ready to be tested in a Spanish population. In the future, assessing and comparing mood-related behaviors in transcultural studies will be possible. Keywords: Circadian rhythms; daily rhythms; mood; psychometric; chronobiology.

Social jetlag in health and behavioral research: a systematic review

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Biological adaptability under seasonal variation of light/dark cycles

ABSTRACT 3A substantial amount of experimental models designed to understand rhythms entrainment and the effects of different regimens of light exposure on health have been proposed. However, many of them do not relate to what occurs in real life. Our objective was to evaluate the influence of “seasonal-like” variation in light/dark cycles on biological rhythms. Twenty adult male Wistar rats were assigned to three groups: control (CT), kept in 12:12 light/dark (LD) cycle; long photoperiod/short photoperiod (LP/SP), kept in 16.5:7.5 LD cycle for 18 days (phase A), then 17 days of gradual reductions in light time (phase B), then 18 days of shorter exposure (7.5:16.5 LD cycle, phase C); short photoperiod/long photoperiod (SP/LP) group, with same modifications as the LP/SP group, but in reverse order, starting phase A in 7.5:16.5 LD cycle. Activity and temperature were recorded constantly, and melatonin and cortisol concentrations were measured twice. Activity and temperature acrophases of all groups changed according to light. The correlation between activity and temperature was, overall, significantly lower for SP/LP group compared with LP/SP and CT groups. Regarding melatonin concentration, LP/SP group showed significant positive correlation between phase A and C (p = 0.018). Animals changed temperature and activity according to photoperiod and demonstrated better adaptability in transitioning from long to short photoperiod. Since this model imitates seasonal variation in light in a species that is largely used in behavioral experiments, it reveals promising methods to improve the reliability of experimental models and of further environmental health research.