The need to find complementary approaches, based on a holistic perspective of the human being, takes on its full meaning in a political context that recommends efficient health programs. Self-induced cognitive trance is one of these complementary approaches, which induce a non-ordinary state of consciousness. The aim of this work is to evaluate whether learning self-induced cognitive trance can improve the quality of life of people with chronic pain. Participants will participate in two times two days workshop aiming at learning how to self-induce cognitive trance. Pain, Fatigue, anxiety, depression, attitudes towards pain, and quality of life will be assessed before and after each workshops. Two follow-ups at 6 and 12 months afer the last workshop will be caried out were outomes will be assessed. Furthmore, questionnaires related to the phenomenology of self-induced cognitive trance will be adeministrered. Investigators also proceeded to interveiwes after the second workshop to gather qualitative information.