Women are twice as likely as men to experience depression across various cultures and ethnicities, whether measured as diagnosed disorders or subclinical symptoms. This gender difference is influenced by a combination of factors, including gender differences in stress responses, exposure to stressors, and biological, social, and psychological factors. Research suggests that women experience more chronic strains, such as poverty, harassment, and lack of respect, and are more likely to be victims of sexual abuse. These experiences can increase vulnerability to depression. Women also experience higher reactivity to stress, which may be due to differences in biological responses, self-concepts, and coping styles. Biological factors include the hypothalamic-pituitary-adrenal (HPA) axis, which regulates stress responses. Women may be more likely to have a dysregulated HPA response, making them more vulnerable to depression. Additionally, women's self-concepts may be more negative, and they may be more prone to rumination, a coping style that focuses inward on distress rather than taking action to relieve it. Social pressures during adolescence, such as conforming to gender roles, can also contribute to the gender difference in depression. Girls may feel restricted in their opportunities and choices, leading to increased stress and vulnerability to depression. The interaction between stress experiences and reactivity plays a significant role in the development of depression. Stressful experiences can sensitize biological and psychological systems, increasing the likelihood of depression, while stress reactivity can impair problem-solving and lead to new stressors. Understanding the gender difference in depression is important for both clinical and research purposes. It helps in understanding the causes of depression in general and highlights the need for targeted interventions. Future research should explore how culture and ethnicity affect the gender difference in depression, as well as the reciprocal effects of biological, social, and psychological systems on each other. The gender difference in depression is a complex phenomenon influenced by multiple factors, and a comprehensive understanding is essential for effective treatment and prevention strategies.Women are twice as likely as men to experience depression across various cultures and ethnicities, whether measured as diagnosed disorders or subclinical symptoms. This gender difference is influenced by a combination of factors, including gender differences in stress responses, exposure to stressors, and biological, social, and psychological factors. Research suggests that women experience more chronic strains, such as poverty, harassment, and lack of respect, and are more likely to be victims of sexual abuse. These experiences can increase vulnerability to depression. Women also experience higher reactivity to stress, which may be due to differences in biological responses, self-concepts, and coping styles. Biological factors include the hypothalamic-pituitary-adrenal (HPA) axis, which regulates stress responses. Women may be more likely to have a dysregulated HPA response, making them more vulnerable to depression. Additionally, women's self-concepts may be more negative, and they may be more prone to rumination, a coping style that focuses inward on distress rather than taking action to relieve it. Social pressures during adolescence, such as conforming to gender roles, can also contribute to the gender difference in depression. Girls may feel restricted in their opportunities and choices, leading to increased stress and vulnerability to depression. The interaction between stress experiences and reactivity plays a significant role in the development of depression. Stressful experiences can sensitize biological and psychological systems, increasing the likelihood of depression, while stress reactivity can impair problem-solving and lead to new stressors. Understanding the gender difference in depression is important for both clinical and research purposes. It helps in understanding the causes of depression in general and highlights the need for targeted interventions. Future research should explore how culture and ethnicity affect the gender difference in depression, as well as the reciprocal effects of biological, social, and psychological systems on each other. The gender difference in depression is a complex phenomenon influenced by multiple factors, and a comprehensive understanding is essential for effective treatment and prevention strategies.