: It significantly interferes with a person's ability to handle daily activities, such as sleeping, eating, and working.

: Changes in appetite or weight, chronic fatigue, sleep disturbances (insomnia or oversleeping), and unexplained aches or pains.

: Difficulty concentrating, memory problems, indecisiveness, and thoughts of death or suicide. Contributing Factors Depression - National Institute of Mental Health (NIMH)

: Unlike occasional sadness, depressive symptoms must persist for at least two weeks to be diagnosed.