From the BBC:

Where hyenas are used to treat mental illness By Richard Hooper

BBC World Service

17 October 2013

… “There is a belief in my country that hyenas can see everything including the evil spirits people think cause mental illness,” says Hab. “So in Mogadishu, you will find hyenas that have been brought from the bush and families will pay £350 ($560) to have their loved one locked in the room overnight with the animal.”

The expensive treatment – more than the average annual wage – is as brutal as it sounds. By clawing and biting at the patient, the hyena is thought to force the evil spirit out. Patients, including young children, have been known to die during the process. …

WHO estimates that one in three Somalis either is or has been affected by mental illness, compared to a global average of one in 10. In parts of the country, where the population has been the most psychologically scarred from decades of conflict, the rate is even higher. Cases of post-traumatic stress disorder are common and the situation is further complicated by widespread substance abuse.

“Khat is a big, big problem,” says Hab of the herbal stimulant which has been chewed for centuries in East Africa. Side effects are thought to include anxiety and even psychosis. “We treat them in the hospital and they leave, but then they start eating khat again. Sometimes I see the same patients seven or eight times.”