Bipolar disorder, previously called manic depression, is a condition that affects your moods, which can swing from one extreme to another.

If you have bipolar disorder, you will have periods or episodes of depression and mania. The two extremes are characterised as follows:

• depression where you feel very low, and
• mania where you feel very high. (If your symptoms are slightly less severe, it is known as hypomania).

Both extremes of bipolar disorder have other symptoms associated with them (see 'symptoms' section).

Unlike simple mood swings, each extreme episode can last for several weeks or longer. The high and low phases of the illness can be so extreme that they interfere with your daily life.

The pattern of mood swings in bipolar disorder varies widely between individuals. Some people only have a couple of bipolar episodes in their lifetime and are stable in between, while others may experience many episodes.

The depression phase

The depression phase often comes first. Initially, you may be diagnosed with clinical depression, and then have a manic episode some time later (sometimes years later), after which your diagnosis might change.

During a phase of depression, you may have overwhelming feelings of worthlessness that often lead to thoughts of suicide.

The manic phase

During a manic phase, you may feel extremely happy and have lots of ambitious plans and ideas. You may also spend large amounts of money on things that you cannot afford. Not feeling like eating or sleeping, talking quickly, and becoming annoyed easily, are also quite common.

You may be very creative and feel that mania is an extremely positive experience. However, during a manic phase, you may also have symptoms of psychosis, when you see or hear things that are not there.

How common is bipolar disorder?

The exact cause of bipolar disorder is not fully understood, but the condition seems to run in families. It is a relatively common condition, with around 1 person in 100 being diagnosed as having bipolar disorder.

Bipolar disorder can occur at any age, but often develops between 18-24 years of age. Both men and women, and people from all backgrounds can develop it.

If you have bipolar disorder, it may have implications for driving. See the 'useful links' section for how to inform the DVLA about medical conditons.