Warm-Day Matters: Associations Between Non-Optimal Temperature Exposure and Mental Health Hospitalizations in Hong Kong

Exposure to non-optimal temperatures poses significant risks to human health, yet evidence on mental health outcomes remains limited. This study examined associations between daily temperature exposure and hospital admissions for mental disorders in Hong Kong from 2006 to 2019. Daily hospitalization data, including both emergency and non-emergency admissions, were obtained from the Hong Kong Hospital Authority, encompassing all public hospitals across 18 districts. Generalized Additive Models (GAM) combined with Distributed Lag Non-linear Models (DLNM) were employed to investigate temperature effects. Results indicated a significant adverse effect of cold temperatures exclusively on persistent mental disorders due to other diseases (physical illness related), while a protective effect was observed for schizophrenia, mood disorders, other non-organic psychoses, and adjustment reactions. Notably, moderate-hot day exposure (27–32 °C) emerged as an important risk factor, particularly during prolonged heat events. Additionally, female patients demonstrated higher vulnerability compared to males. Our findings highlight differential effects of temperature exposure on mental health disorders, emphasizing the necessity for targeted interventions and adaptive strategies to mitigate adverse mental health impacts, particularly among females and during sustained moderate heat exposures.