Huang J, Zuber V, Matthews PM, et al. - Researchers performed a bidirectional 2-sample Mendelian randomization analyses to explore the causal connections between sleep, major depressive disorder (MDD), and Alzheimer disease (AD). They collected genetic associations from the largest genome-wide association studies currently available in UK Biobank (n = 446,118), Psychiatric Genomics Consortium (n = 18,759), and International Genomics of Alzheimer's Project (n = 63,926). They found that AD can have a causal impact on sleep patterns, though they did not find evidence supporting the causal role of disturbed sleep patterns in AD or evidence of a causal association between MDD and AD. After adjustment for multiple comparisons, we found that being a “morning person,” shorter sleep duration, less likely to report long sleep, earlier timing of the least active 5 hours, and a smaller number of sleep episodes was significantly related to a higher risk of AD. A higher risk of AD was also linked with lower risk of insomnia