Risk Factors for Major Depressive Disorder

Maria is a 28-year-old woman who has been experiencing persistent feelings of sadness and a lack of interest in activities she used to enjoy for the past six months. She often feels fatigued, has trouble concentrating, and has noticed changes in her sleeping patterns. Concerned about her mental health, she decides to seek professional help. After a thorough assessment, her therapist diagnoses her with Major Depressive Disorder (MDD).

In understanding Maria's situation, it is essential to analyze the various contributing factors to psychological disorders such as MDD. Which of the following factors is most consistently identified as a risk factor for developing Major Depressive Disorder?