According to the American Psychiatric Association, “Depression is a serious medical illness that negatively affects how a person feels, the way he/she thinks, and how a person acts.”
Depression causes sadness and loss of interest in daily activities. Depression causes serious physical and emotional changes and decreases the ability of the person to perform daily activities like office and homework. Major life events, such as bereavement or the loss of a job, can lead to trusted Source depression. Depression can last for years, months or weeks.