In patients with cystic fibrosis, a deterioration in lung function around age 18, the age of transfer from pediatrics to adult care services, has been observed. Transfer is only one step in a transition process from pediatric to adult care taking place from age 12 to 24. Adolescence is a period of identity construction during which the disease alters self-image and self-esteem, and a period of empowerment in the management of the disease involving a re-appropriation of it. During this period, coping strategies and psychosocial skills are important to face all the issues that the adolescent encounters. Interventions for youth with chronic illnesses rarely incorporate this dimension. Peer support or peer-mentoring is one avenue for developing these coping skills. Peer support encompasses mutual support between people who are coping or have coped with similar challenging life experiences. Individuals with similar experiences would represent more credible role models to stimulate positive change in their peers. The function of peer support are to provide emotional, experiential, informational support.The effect of peer support improves social integration, coping skills, sense of self-efficacy of the peers being helped. Promotion of healthy youth behaviors by youth is the most widely evaluated youth engagement strategy in the community health sector. Peer-assisted devices have been tested to improve medication adherence and health status with youth with juvenile arthritis, asthma, and liver transplant recipients. By sharing their experience of a successful transition, young adults with cystic fibrosis may be able to help their adolescent peers better understand this transition. Our hypothesis is that implementing peer support with adolescents with cystic fibrosis improves their sense of self-efficacy, a dimension of coping skills.To our knowledge, there are no research studies on peer support in cystic fibrosis in France or abroad. Patients are recognized as partners capable of sharing their experiential knowledge with patients with a similar disease.

But this raises questions about the recruitment, supervision, preparation for peer-help and the role of these patients; about the effects of their involvement for themselves (valorization, anxiety) and for their peers (re-assurance, feeling of personal effectiveness). This justifies conducting an exploratory study to assess the feasibility of a peer-support intervention for youth with cystic fibrosis.

Concerning the patient /mentee:

Inclusion Criteria:

• patient affected by cystic fibrosis
• patient able to understand and read French
• patient from 15 to 19 years , in a process of transition on paediatric care to adult care
• with a follow-up on a paediatric Cystic Fibrosis Centers Competences (CRCM)
• did not participate in the Phase 1 co-construction workgroup
• affiliated to the social security system
• having agreed to participate and signed the consent for an adult patient, or legal guardian having agreed to participate and signed the consent for a minor patient

Exclusion Criteria:

• patient with transplant
• patient with cystic fibrosis transmembrane regulator-related disorders (CFTR RD) or Screen Positive Inconclusive Diagnosis (SPID) Cystic Fibrosis
• patient with a curator, tutor or under the protection of a conservator
• pregnant or breastfeeding patient

Concerning the mentor/peer-supporter (post period):

Inclusion Criteria * :

• affected cystic fibrosis
• able to understand and read French
• young adult, 19 to 24 years old
• with a follow-up on the adult CRCM (transition completed)
• affiliated to the social security system
• have agreed to participate and signed the consent form
• did not participate in the Phase 1 co-construction workgroup

Exclusion Criteria * :

• patient with transplant
• patient with CFTR RD or SPID Cystic Fibrosis
• patient with a curator, tutor or under the protection of a conservator
• pregnant or breastfeeding patient