The first set of considerations for all people is that the person is physiologically stable, free from internal pain and irritation, and lives and participates in environments that are safe, healthy, stimulating, pleasurable and occupied by people who are caring and supportive. Intervention and support programs should be preceded or accompanied by the achievement of these elements. Indeed, the presence of optimal physiological and environmental conditions can be the dominant factor in the accomplishment or facilitation of intervention and support objectives.