Depression is a feeling of persistent sadness that is accompanied by a general malaise.
Symptoms. Low morale, hopelessness and loss of interest in normal daily activities, feelings of guilt or worthlessness, disturbed sleep or appetite, tiredness and lack of concentration.
Depression can substantially hinder performance at work or school, if it becomes chronic or recurrent and diminishes the ability to cope with everyday life. If mild, it can be treated without drugs, but depression may require medication and professional psychotherapy when it is moderate or severe. In its most severe form, it can lead to suicide.