It is hard to determine when someone has excessive sexual desire. It is often the environment of the person or the person who is limited by it.
Not much is known about the physical causes of this disorder. Possibly hormones and/ or anomalies in the brain play a role. The patient with a manic disorder (mood disorder) may have excessive sexual desires. Certain medicines, such as some medicines against restless legs and Parkinson's disease, may cause excessive sexual desire. Alcohol and some narcotics, such as cocaine and amphetamin, can also have this effect.
If a person feels considerable distress because of his or her sexual desire, this can be a reason to regard the desire as excessive.
This is often treated with medication.