Depression

Adverse life events commonly precede all types of major depression, irrespective of the clinical picture and there is no clear relationship between apparent cause of depression and response to antidepressant drug treatment. Up to half of the patients with a major depressive illness are not diagnosed and those who are diagnosed are often not adequately treated.

Prevalence of Depression

� Depressive disorders are common. The prevalence of major depression in people seen in primary care is between 5% and 10%, and two to three times as many people have depressive symptoms but do not meet the criteria for major depression.
� About two thirds of adults will at some time experience depressed mood of sufficient severity to influence their activities.
� Most depressive states are at the mild to moderate end of the spectrum and it is these that are mainly seen in primary care.
� One study in Canada found that women were approximately twice as likely as men to experience a depressive episode within a lifetime.
� Lifetime risk for major depression is 15% overall: 19% for women and 10% for men.

Presentation

� Only about half of people with major depression are identified as having this by their GP. People often present with mainly physical symptoms.
� Many people have a physical illness, diverting attention away from their mental state.
� Depression should be particularly suspected if there is a history of major depression, a family history of mood disorder or a history of suicide attempt. .
� Professionals should consider asking their patients two questions to screen for depression.7 During the past month, have you:

* Felt low, depressed or hopeless?
* Had little interest or pleasure in doing things?

� Assessment should include assessment of suicide risk. Suicide ideation can develop at any time during treatment.

Major depression

� Major depression is defined by the presence of at least five out of the following nine symptoms (and must include depressed mood and/or loss of interest or pleasure):

* Depressed mood
* Loss of interest or pleasure in almost all activities
* Significant weight loss or gain, or change in appetite
* Insomnia or hypersomnia
* Psychomotor agitation or retardation (observable by others)
* Fatigue or loss of energy
* Feelings of worthlessness or excessive or inappropriate guilt
* Diminished ability to think or concentrate, or indecisiveness
* Recurrent thoughts of death (not just fear of dying) or suicidal thoughts/actions

� Symptoms must have been present for at least the last 2 weeks and cause clinically significant distress or impaired functioning.
� The symptoms are not due to a physical/organic factor (e.g. substance abuse) or illness and are not better explained by bereavement (although this can be complicated by major depression).
� Mild to moderate major depression ranges from a threshold number (five) of symptoms with minimal functional impairment through to marked symptoms and impairment of function.

Complications of Depression

� Depression is a major cause of impaired quality of life, reduced productivity, and increased mortality. Social difficulties are common (e.g. social stigma, loss of employment, marital break-up). People with depression are at increased risk of suicide.
� Associated problems, such as anxiety symptoms and substance misuse, may cause further disability.