The built environment significantly influences mental health through both direct and indirect mechanisms. Direct effects include housing quality, crowding, noise, indoor air quality, and light. Poor-quality housing is linked to increased psychological distress, while high-quality housing is associated with better mental health. High-rise housing is particularly detrimental to the psychological well-being of mothers with young children, as it promotes social isolation and limits play opportunities. Crowding increases psychological distress but does not necessarily lead to serious mental illness. Noise, especially from airports, is associated with increased psychological distress, while malodorous pollutants and toxins like lead and solvents can cause behavioral disturbances. Insufficient daylight is linked to increased depressive symptoms. Indirectly, the built environment affects mental health through psychosocial processes such as personal control, social support, and restoration. Personal control is enhanced by environments that allow individuals to manage their surroundings, while lack of control can lead to helplessness. Social support is influenced by the design of residential spaces, with proximity and accessibility to social spaces promoting interaction. Restoration is facilitated by natural elements like trees, water, and natural landscapes, which help reduce stress and improve cognitive function. The built environment also impacts mental health through its influence on neighborhood quality, with moving to middle-income areas associated with improved mental health. Institutional settings, such as psychiatric facilities and Alzheimer's care, are designed to promote social interaction and reduce psychological distress. Design features like smaller units, reduced noise, and homelike environments are beneficial for Alzheimer's patients. Research highlights the need for more studies to understand the complex relationships between the built environment and mental health, particularly considering socioeconomic factors and environmental risks. The built environment's role in mental health is multifaceted, with both direct and indirect effects, and further research is needed to develop effective interventions and models.The built environment significantly influences mental health through both direct and indirect mechanisms. Direct effects include housing quality, crowding, noise, indoor air quality, and light. Poor-quality housing is linked to increased psychological distress, while high-quality housing is associated with better mental health. High-rise housing is particularly detrimental to the psychological well-being of mothers with young children, as it promotes social isolation and limits play opportunities. Crowding increases psychological distress but does not necessarily lead to serious mental illness. Noise, especially from airports, is associated with increased psychological distress, while malodorous pollutants and toxins like lead and solvents can cause behavioral disturbances. Insufficient daylight is linked to increased depressive symptoms. Indirectly, the built environment affects mental health through psychosocial processes such as personal control, social support, and restoration. Personal control is enhanced by environments that allow individuals to manage their surroundings, while lack of control can lead to helplessness. Social support is influenced by the design of residential spaces, with proximity and accessibility to social spaces promoting interaction. Restoration is facilitated by natural elements like trees, water, and natural landscapes, which help reduce stress and improve cognitive function. The built environment also impacts mental health through its influence on neighborhood quality, with moving to middle-income areas associated with improved mental health. Institutional settings, such as psychiatric facilities and Alzheimer's care, are designed to promote social interaction and reduce psychological distress. Design features like smaller units, reduced noise, and homelike environments are beneficial for Alzheimer's patients. Research highlights the need for more studies to understand the complex relationships between the built environment and mental health, particularly considering socioeconomic factors and environmental risks. The built environment's role in mental health is multifaceted, with both direct and indirect effects, and further research is needed to develop effective interventions and models.