Supported by various funding sources, the APA and its members have played major roles in examining points of contention in the field and addressing uncertainties about psychiatric illness and its treatment, as well as the relationship of individual mental health concerns to those of the community. Controversies have related to anti-psychiatry and disability rights campaigners, who regularly protest at American Psychiatric Association offices or meetings. In 1971, members of the Gay Liberation Front organization sabotaged an APA conference in San Francisco. In 2003 activists from MindFreedom International staged a 21-day hunger strike, protesting at a perceived unjustified biomedical focus and challenging APA to provide evidence of the widespread claim that mental disorders are due to chemical imbalances in the brain. APA published a position statement in response and the two organizations exchanged views on the evidence.