The two core features of depression include a low mood and a lack of pleasure from pleasurable activities. People often report not being able or motivated to do the things that they enjoyed doing before. The other common symptom among patients is tiredness and lethargy. The tiredness lasts the whole day and prevents most people from doing what they need to do. Other symptoms of depression include:

* Significant change in appetite or weight
* Insomnia or hypersomnia nearly everyday
* Psychomotor agitation or retardation
* Fatigue or loss of energy nearly every day
* Feeling of uselessness of inappropriate guilt
* Decresed ability to think, concentrate or to make decision nearly everyday
* Recurrent thoughts of death or suicidal ideas or suicidal plans of attempts

To make a diagnosis of Major Depression an individual requires a minimum of five of these symptoms for at least two weeks duration. Other conditions such as medical illnesses that cause depression (eg: hypothyroidism or Parkinson’s Disease) or drug use leading to depression need to be ruled out. The depression must have caused significant impairment in the social and occupational functioning of the individual. A common characteristic among people with depression is negative thoughts. These thoughts are caused by the neurochemical change that occurs in depression and are often unshakeable. These thoughts may push a person to feel that life is worthless and that it’s better that they were dead.