Bipolar disorder, also referred to as manic depression, is a mood disorder manifesting in episodes of depression and elation that are distinct to the individual personality and entirely out of character.  Bipolar I Disorder is characterised by more severe manic episodes whilst Bipolar II Disorder tends to have less severe manic episodes (hypomania) and more prolonged depressive episodes.

The most common age of onset is mid-late 20s but it can arise in childhood and adolescence. A seasonal component is not uncommon with manic episodes more likely in the spring and summer with depressive ones more in the winter. Rapid cycling (4 or more mood swings a year) Bipolar Disorder can be particularly disruptive with mood swings occurring within hours. Severe episodes, either manic or depressive, can be associated with psychotic symptoms e.g. delusions and hallucinations. Symptoms of a manic episode include euphoria and over-optimism, inflated self-esteem and boasting, pressured speech and racing thought, overactivity and disinhibition, irritability and aggressive behaviour, poor judgment, increased libido, reckless and inappropriate behaviour e.g. overspending and drug/alcohol misuse, short Attention span, and in mania, psychotic symptoms such as hallucinations and delusions. Depressive symptoms are as for depressive disorder, namely pervasively low mood, reduced energy and pleasure in previously enjoyable activities, disturbed sleep and appetite, restless agitation or significant slowing of movement and thoughts, loss of confidence, and in severe cases, suicidal thoughts. 

A number of factors are thought to predispose an individual to bipolar disorders. Family history significantly increases the likelihood of developing a bipolar disorder: approximately 20% of sufferers have a first-degree relative with a mood disorder.  Imbalances of neurotransmitter (serotonin and noradrenaline) and hormonal metabolism have both been identified in precipitating manic and depressive episodes and illicit drugs and alcohol can exacerbate episodes. Traumatic or stressful events, bereavements and other losses can trigger both manic and depressive episodes. 

Effective treatment of bipolar disorder, where insight is often limited, especially in manic episodes, relies on an open and honest relationship with professionals, patient education and family support. Mood stabilising medications (e.g. lithium and anticonvulsants in particular Depakote) target the neurotransmitters involved in mood swings. Anti-psychotic medications (e.g. olanzapine and quetiapine) are sometimes necessary to deal with severe manic symptoms and psychotic symptoms occurring in both mania and depression. Antidepressants should be used with caution as they may trigger a manic episode. Cognitive Behavioural Therapy helps the individual learn strategies for predicting and better managing disturbances in mood, reducing relapses and minimising their negative impact. Individual and family therapy sessions help deal with previous adverse life events and relationship difficulties further minimising the risk of relapse.