... Despite the large body of developmental literature on friendships within normative and clinical populations of youth, little is known about the presence and quality of friendships of youth with chronic illnesses, particularly youth with CF (Meijer, Sinnema, Bijstra, Mellenbergh, & Wolters, 2000;Spirito, DeLawyer, & Stark, 1991). Most often, pediatric research has focused on broad domains such as psychosocial functioning, social adjustment, or social activities (Meijer et al., 2000;Spirito et al., 1991), or on disease-related peer roles, such as certain forms of social support (e.g., Barker, Driscoll, Modi, Light, & Quittner, 2012;Graetz, Shute, & Sawyer, 2000;La Greca et al., 1995). Social support from peers may promote improved quality of life, adaptive psychological adjustment, and in some cases, greater treatment adherence (Bearman & La Greca, 2002;Helgeson, Lopez, & Kamarck, 2009;Herzer, Umfress, Aljadeff, Ghai, & Zakowski, 2009;La Greca et al., 1995). ...