Your child may have bipolar disorder if he experiences rapidly changing, strong emotions without a visible cause, reports the National Institute of Mental Health. A qualified doctor should examine a child exhibiting these symptoms to determine whether the child has bipolar disorder or another condition.
Mood cycles are the key characteristic of bipolar disorder, explains NIMH. They can take the form of mania or depression. Some children also have mixed episodes, which have symptoms of both mania and depression.
Mania usually accompanies an increase in energy, according to NIMH. The child is generally very happy or silly, and he may get overly excited about small things. He may speak more often or talk very quickly and not get tired easily even if he did not sleep much. Children may get irritated easily. Older children and teenagers may talk about sex and take uncharacteristic risks.
Depression often manifests as feelings of sadness, guilt and low self-esteem, notes NIMH. It may also accompany unusual sleep patterns, which can take the form of sleeping either too much or too little. Appetite changes, tiredness and lack of interest in things that the child normally enjoys may also appear.
Adults with bipolar disorder may have infrequent mood episodes, but children usually cycle through them very quickly, reports WebMD. These episodes may last for a week or more at a time, but children can also cycle though mania and depression in the course of a single day.