The symptoms of depression may vary from person to person and also depend on the severity of the depression. Depression causes changes in thinking, feeling, behaviours and physical well being. These may sound like a normal stress or fatigue symptoms but imagine if these symptoms lasted for weeks or even months. And imagine feeling this way almost all the time. Depression is present if you experience many of these symptoms for at least several weeks. When these symptoms persist on, the depressed will become anti social, abusive use of drug and alcohol to numb themselves and their feelings. Being extremely bad tempered, pessimistic and overly stubborn is a norm in almost all depress cases. And more dangerously, repeated thoughts of committing suicide strikes.