One out of every five doctors treating people with ALS, an incurable disease that disrupts the nervous system and disables muscles, has been asked by a patient to remove breathing equipment, according to a study by Kitasato University.

The study found that 284 out of around 1,500 doctors had such an experience with patients suffering from amyotrophic lateral sclerosis, a progressive disorder of the nervous system. Nine said there have been cases in which they granted the request, but most said they refused because they believe it would constitute murder.

More than half the doctors, however, approved of removing breathing equipment in certain conditions.

The study comes as a growing number of ALS patients, of which there are around 8,000 in Japan, are asking for their breathing equipment be removed when they become unable to communicate due to the disease. As ALS progresses, it becomes harder for patients to walk, eat and even breathe.