A new, large-scale study conducted in China has shown that clusters of unhealthy daily habits in adolescents can predict a higher risk of developing both anxiety and depression over time. Led by researchers Wanyu Che, Ziyan Ruan and Xiaoyan Wu of Anhui Medical University, the study followed 6,656 teenagers across eight regions and tracked them for a year. The findings, published in BMC Psychiatry, suggest that groups of lifestyle risks may collectively heighten mental health vulnerability in adolescence.
Adolescence is a period of rapid physical and mental development, during which daily routines can have lasting impacts. The researchers note that common behaviours—such as skipping meals, spending long hours on screens, or staying up late—often do not occur in isolation but tend to cluster within individuals, potentially shaping mental health trajectories.
The study involved teenagers living in a mix of urban and rural settings, spanning first- and second-tier cities. The average participant was about 14 years old, with the sample representing both middle- and high-school students. Assessments were conducted at baseline in late 2021 and again roughly a year later, using electronic questionnaires completed on smartphones during class time.
Participants were surveyed about 15 unhealthy behaviours to create a detailed picture of their daily habits. These included smoking and alcohol use, physical inactivity, inadequate sleep duration, late bedtimes, and high screen time on weekdays and weekends. Dietary factors encompassed insufficient fruit or vegetable intake, frequent fast food consumption, skipping breakfast and high consumption of sugary drinks. The questionnaire also probed thoughts, plans and actions related to suicide.
To measure mental health, the researchers used standard self-report scales for anxiety and depression and identified students who exceeded symptom cutoffs for both conditions at the one-year follow-up, indicating comorbidity.
At the one-year mark, 13.6 percent of participants met criteria for both anxiety and depression. The burden was higher among girls, and higher still among students facing heavy academic pressures, those from poorer families, and those with relatively few friends.
Using statistical modelling, the researchers grouped students by patterns of unhealthy behaviours into four clusters. The low-risk group comprised about 24 percent of participants and reported very few of the 15 behaviours.
The second cluster, making up roughly 40 percent of pupils, was characterised by poor dietary habits, including skipped breakfasts, frequent fast food consumption, and limited fruit and vegetable intake.
The third category represented about 22 percent and combined sedentary behaviours with extensive screen time, reflecting low physical activity alongside high device use.
The final cluster, comprising almost 14 percent, displayed multiple unhealthy behaviours, with high rates across almost all 15 factors and a greater likelihood of reporting suicidal thoughts or actions alongside poor sleep and diet.
The researchers also examined the overall number of unhealthy habits, finding that more than half of participants engaged in four to six of the habits, while about a quarter reported seven or more.
After adjusting for potential confounders such as family income, number of friends, academic pressure and family history of depression, those in the sedentary and multi-behaviour clusters faced a substantially higher risk of developing the comorbid condition compared with the low-risk group. The risk rose in line with the total number of unhealthy habits: teenagers with seven or more poor habits had almost triple the odds of experiencing both anxiety and depression than those with three or fewer.
The researchers tested the robustness of their findings by a second analysis that excluded suicide-related items from the behaviour list. Even with the 12 remaining lifestyle factors, the grouping remained a strong predictor of future anxiety and depression, indicating that the behavioural profile itself contributes independently to mental health vulnerability.
The authors propose that these clustered behaviours reflect a shared underlying vulnerability rather than discrete triggers for either condition alone. By identifying patterns of behaviours rather than isolated actions, the study suggests a potential pathway for early prevention and targeted support in adolescent development.
The study relies on self-reported data, which can introduce bias if teenagers misremember or choose not to disclose certain behaviours. It also only includes adolescents currently enrolled in school, leaving questions about how findings apply to youths outside formal education. As an observational study, it cannot establish causality, and unmeasured factors such as early childhood trauma or neighbourhood environments could influence both daily habits and mental health outcomes.
Looking ahead, the authors caution that further research is needed to determine whether school or community programmes that address these clustered behaviours can reduce the incidence of anxiety and depression among adolescents. Addressing multiple health behaviours simultaneously may offer a more effective preventive approach than targeting single habits in isolation.
The study, authored by Wanyu Che, Ziyan Ruan, Shuman Tao, Meng Wang, Yuxuan Cao, Yaqian Niu, Yuming Chen, Tangjun Jiang, Tingting Li, Liwei Zou, Fangbiao Tao and Xiaoyan Wu, contributes to the understanding of how adolescent lifestyle patterns relate to the comorbidity of anxiety and depression. It marks a step forward in recognising the interconnected nature of physical and mental health during adolescence.
