Depression is a mental health condition that involves a prolonged period of feeling sad or hopeless, and can impact a person's ability to function. It can also cause physical symptoms, such as aches and pains. 

Symptoms 

Feeling sad, irritable, or emptyLoss of interest in activitiesDifficulty sleepingChanges in appetite or weightFeeling tired or low in energyFeelings of guilt or low self-worthThoughts of suicide or self-harmDifficulty concentratingCausesDepression can be caused by a combination of genetic, biological, environmental, and psychological factors. 

Neurotransmitter changes in the brain may also play a role. 

Treatment 

Treatment options include psychotherapy and medications.The effectiveness of treatment depends on the type and severity of depression.For most people, a combination of psychotherapy and medications is more effective than either alone.Helping yourself Exercise, Eat healthy foods and drink plenty of water, Express yourself, Don't dwell on problems, and Notice good things.