Major depression is when more of the symptoms of depression are present and more intense or severe. It can occur as a one off episode (single episode) or may occur several times in a lifetime (recurrent depression). It affects daily activities like sleeping, eating, studying, work and activities which were once enjoyed are no longer pleasurable. Major depression responds well to treatment and many people

Major depression can occur as a result of a single traumatic event in life or can manifest slowly due to a number of personal disappointments and problems. Some people can develop the symptoms of major depression without any obvious causes.

Dysthymic depression

Dysthymic depression is characterized by a depressed mood virtually everyday which lasts for a minimum of 2 years, often longer. It is a low to moderate form of depression, with the symptoms less severe than that of major depression however they are harder to treat. Dysthymic depression symptoms are not as severe as to effect daily life although they do cause distress and interference with some aspects of life. Psychotherapy is effective in treating Dysthymic depression and some people also respond well to anti depressants.

Unspecified depression

This diagnosis is made when a person's symptoms are not severe enough to be classed as having major depression and have not had the symptoms long enough to be diagnosed as having dysthymic depression. If someone is obviously depressed but does not fit into any other category then this diagnosis is usually made.

Adjustment disorder, with depression

This is also know as reactive depression and occurs directly as a result of a traumatic life event or crisis. If the symptoms are severe enough then a diagnosis of major depression would be made rather than adjustment disorder.

Bipolar depression

Bipolar depression (manic depression) is characterised by cycles of high (mania) and low (depression) moods in conjunction with other symptoms not present in other forms of depression. The mood cycling can occur rapidly or more commonly over time, displaying all the symptoms of a depressive disorder when in the low cycle and excess energy, over talkative and overactive when in a manic cycle. The manic cycle can affect social behaviour, judgement and thinking which can cause severe problems such as getting into debt because of excessive spending, substance misuse which could lead to further problems, holding down jobs, relationship problems.

Treatment for bipolar disorder is available, although through the manic episodes the person often does not think that they need treatment and often stops taking or refuses treatment. If mania is left untreated it may develop into psychosis.