Ilona Merikanto and colleagues published a population-based study in the journal Sleep Health on 2026-08-31 regarding the link between circadian rhythm and mental health. ^[1] Researchers found that mental health problems, particularly anxiety and depression disorders, are particularly pronounced among extreme evening types compared to morning types. ^[2] Researchers published a study in the journal Sleep Health finding that people who prefer late bedtimes and wake times are more likely to experience symptoms of anxiety and depression. ^[3] The association between being a night owl and anxiety disorders appeared to be related to poor recovery from work and challenges in balancing work and personal life. ^[4] The study examined 2,266 working-age individuals in Finland, dividing them into morning, evening, and intermediate types based on their circadian rhythms. ^[5] Participants with extreme evening chronotypes reported worse recovery after work and greater difficulty maintaining a balance between work and personal life. ^[6] The study included 2,266 working residents of Finland who were categorized into 'larks', 'owls', and intermediate chronotypes. ^[7] A review published in Brain Medicine on August 25 highlighted that scientists have largely focused on monophasic sleep blocks, despite the prevalence of segmented sleep patterns globally. ^[8] Mohammed Al-Abri, a sleep medicine researcher at Sultan Qaboos University in Muscat, Oman, noted that many people in Muslim-majority countries wake before dawn for prayers and often take afternoon naps to recover. ^[9] Researchers reported in January 2025 in Obesity that propensity for napping is highly heritable, and individuals who nap against their genetic predisposition showed an increased risk of obesity. ^[10] The researchers noted that the study did not prove that a late sleep schedule itself directly causes mental disorders. ^[11]