RecruitingBehavioural interventionFinal Prototype Refinement of Adaptive Cell Phone SupportThe goal of this feasibility pilot trial is to finalize the design of a mobile health intervention for promoting medication adherence in a population of adolescents and young adults with chronic health conditions. The main question\[s\] it aims to answer are: 1. Is the final version of the intervention sufficiently feasible, usable, and acceptable for evaluation in a randomized clinical trial? 2. Do participants show improvements in medication adherence during their field testing of the intervention?