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Abstract: Background: Depression has been associated with several circadian rhythm perturbations, suggesting a disruption of the circadian clock system in affective disorders. The interaction of several circadian clock genes generates these daily circadian rhythms. Methods: This cross-sectional study evaluated whether circadian gene expression differed between individuals with a history of depression and participants without a similar history. The participants were 60 healthy older adults. Half of the participants had a history of depression. Real-time quantitative polymerase chain reaction was used to measure the circadian gene Clock, BMAL1, Period1, and Period2 messenger RNA levels in peripheral blood leukocytes. Results: Individuals with a history of depression had higher Clock, Period1, and Bmal1 mRNA levels, compared to non-depressed participants. Limitations: Although circadian gene expression fluctuates throughout the day, clock gene mRNA levels were evaluated only in the morning. Conclusions: These results suggest that disruptions of the molecular mechanisms underlying the circadian clock system may be associated with depression. [ABSTRACT FROM AUTHOR]

While walking in nature has been shown to improve affect in adults from the community to a greater extent than walking in urban settings, it is unknown whether such benefits apply to individuals suffering from depression. Using a parallel group design, this randomized controlled trial examined the effects of a single walk in nature versus urban settings on negative and positive affect in adult psychiatric outpatients diagnosed with major depressive disorder (MDD). Participants recruited from a psychiatric outpatient clinic for adults with MDD were randomly assigned to a nature or urban walk condition. Thirty-seven adults (mean age = 49 years) completed a single 60-minute walk. Negative and positive affect were assessed using The Positive and Negative Affect Schedule or PANAS at 6 time points: before the walk, halfway during the walk, immediately post-walk, at home before bedtime, 24 h post-walk, and 48 h post-walk. Controlling for baseline levels of affect before the walk, individuals who walked in nature experienced overall lower levels of negative affect, F (1, 35.039) = 4.239, p =.047, compared to those who walked in urban settings. Positive affect did not differ across walk conditions. The generalizability of results are limited by the small sample size and the presence of more female than male participants. Walking in nature might be a useful strategy to improve negative affect in adults with MDD. Future research should investigate different ways to integrate the beneficial effects of nature exposure into existing treatment plans for psychiatric outpatients with MDD. • Walking in nature can improve affect of psychiatric outpatients with depression. • Negative affect improved for participants who walked in nature (vs. urban settings). • Walking in nature did not impact positive affect. [ABSTRACT FROM AUTHOR]

Background: While walking in nature has been shown to improve affect in adults from the community to a greater extent than walking in urban settings, it is unknown whether such benefits apply to individuals suffering from depression. Using a parallel group design, this randomized controlled trial examined the effects of a single walk in nature versus urban settings on negative and positive affect in adult psychiatric outpatients diagnosed with major depressive disorder (MDD).Method: Participants recruited from a psychiatric outpatient clinic for adults with MDD were randomly assigned to a nature or urban walk condition. Thirty-seven adults (mean age = 49 years) completed a single 60-minute walk. Negative and positive affect were assessed using The Positive and Negative Affect Schedule or PANAS at 6 time points: before the walk, halfway during the walk, immediately post-walk, at home before bedtime, 24 h post-walk, and 48 h post-walk.Results: Controlling for baseline levels of affect before the walk, individuals who walked in nature experienced overall lower levels of negative affect, F(1, 35.039) = 4.239, p = .047, compared to those who walked in urban settings. Positive affect did not differ across walk conditions.Limitations: The generalizability of results are limited by the small sample size and the presence of more female than male participants.Conclusions: Walking in nature might be a useful strategy to improve negative affect in adults with MDD. Future research should investigate different ways to integrate the beneficial effects of nature exposure into existing treatment plans for psychiatric outpatients with MDD. [ABSTRACT FROM AUTHOR]