Symptoms of clinical depression vary from amongst people and ranges from mood swings to memory loss. Depression often manifests itself with a wide array of experiences and becomes difficult to diagnose, if left untreated. Depression, like other illnesses come in different forms. Three of the most common types of depressive disorders are major clinical depression, dysthymia, and bipolar (or manic) depression. Within each type, there are variations in the number, severity and persistence of symptoms.

Major clinical depression can be classified by a number of symptoms including mood swings that interfere with the ability to work, sleep and enjoy once pleasurable activities. Recognizing and understanding the symptoms, however, is the most important step in successful treatment of depression. These symptoms include persistent mood swings, anxiety, irritability and emotional mood swings. Clinical depression also causes fatigue or unexplained loss of energy, loss of enthusiasm, unexplained weight loss or gain and insomnia. Most patients have difficulty concentrating or making decisions, coupled with a feeling of hopelessness and guilt. A decreased interest in sex is noticed in individuals suffering from depression and they are also known to have suicidal tendencies. They often do not respond to treatment for headaches, digestive disorders and chronic pain. Sadly, childhood depression is as serious as adult depression. Symptoms in children usually include, refusal to go to school, reduced interest in extracurricular activities, a fear of their parents dying and low self-esteem.

It is more difficult to understand depression amongst teenagers. As they grow, they try to find who they are and what they believe in. Changes in behavior are normal. However, problems arise when an adolescent feels helpless and hopeless, coupled with a belief that life is not worth living.