These are some symptoms that people have when they're depressed:

depressed mood or sadness most of the time

lack of energy and feeling tired all the time

inability to enjoy things that used to bring pleasure

withdrawal from friends and family

irritability, anger, or anxiety

inability to concentrate

significant weight loss or gain

significant change in sleep patterns

feelings of guilt or worthlessness

aches and pains

pessimism and indifference

thoughts of death or suicide

When someone has five or more of these symptoms
most of the time for 2 weeks or longer,
that person is probably depressed.