Their is a very strong possibility a patient will have to seek out a new doctor to receive PAS services. In states where physician-assisted suicide is legal, very few doctors actual offer the service. It is estimated that in Oregon, the state where it all started, only 2 -3 % of the physicians offer the service.  Most patients seeking physician-assisted suicide usually contact contact the advocacy group Compassion and Choices to locate a physician. There is also no formal training or medical certification offered to doctors. Those that participate in providing this service usually learn from other doctors who have done it.  There has been no large scale study of the effects of the lethal drugs on the body to determine if a patient's pain and suffering is masked.