In 1968, when Anneliese was 16 and still in high school, she began to suffer from convulsions. Court findings had her experiencing her first epileptic attack in 1969.
Soon, Anneliese started experiencing hallucinations while praying. She also began to hear voices, which told her that she was damned.
By 1973 Anneliese was suffering from depression and considering suicide. Her behavior became increasingly bizarre; she tore off her clothes, ate coal and spiders off the floor, and licked up her own urine.
In 1975, when Anneliese Michel was 23 years old, an older woman who accompanied her on a pilgrimage concluded that Michel was suffering from demonic possession because Michel was unable to walk past a certain icon of Jesus Christ and refused to drink the water of a holy spring.
An exorcist in a nearby town examined Michel and believed she was suffering from demonic possession.The bishop issued permission to perform the rite of exorcism according to the Rituale Romanum of 1614. After years of unsuccessful psychiatric treatments, they gave up on medical treatment and chose to rely solely on the exorcisms for healing.
The rites of exorcism were performed over the course of about ten months in 1976. A total of sixty-seven exorcism sessions were held, one or two each week, some lasting up to four hours.
At some point she began talking increasingly about dying to atone for the wayward youth of the day and the apostate priests of the modern church, and refused to eat. Though she had received treatment for epilepsy, by this time, at her own request, doctors were no longer being consulted.
This was because Anneliese mentioned the "demons" to the doctors, explaining that they started to give her orders.The doctors seemed unable to help, and Anneliese lost hope that medicine was going to be able to cure her.
On July 1, 1976, Anneliese Michel died in her sleep. The autopsy report stated that her death resulted from the malnutrition and dehydration due to almost a year of semi-starvation during which time the rites of exorcism were also performed.