Adolescents who combine multiple unhealthy habits—like poor diet, too much screen time, and lack of exercise—face a significantly higher risk of experiencing both anxiety and depression, according to a new study published in BMC Psychiatry. Researchers have long known that individual habits, such as physical inactivity or poor sleep, can affect mental wellbeing. However, in real life, these behaviors rarely occur alone. Teenagers who skip meals, spend long hours on screens, and sleep poorly often do all of these at once. This “clustering” of unhealthy habits has been less studied, especially in relation to combined mental health conditions. To address this gap, researchers wanted to understand whether patterns of multiple unhealthy behaviors could predict which adolescents are most at risk of developing both anxiety and depression. Led by Xiaoyan Wu of Anhui Medical University in China, the research team followed 6,656 adolescents (average age 14 years; 52% female) over a one-year period. Students completed self-reported, smartphone-based surveys that assessed 15 lifestyle behaviors—including diet, physical activity, sleep patterns, alcohol consumption, suicidal behaviors, and screen time—as well …