The goal of this randomized prospective clinical trial is to examine whether phenotypic traits, psychological characteristics, assessed by STAI (engl. The State-Trait Anxiety Inventory) and IPIP50S (engl. International Personality Item Pool) questionnaires, and patients' self-efficacy, assessed by SEMSA (engl. Self-Eficacy Measure for Sleep Apnea) questionnaire, are associated with CPAP adherence after three months of use. The study also evaluates whether a motivational phone call one month after therapy initiation improves CPAP adherence at the three-month follow-up. The main questions it aims to answer are: * Are phenotypic and psychological traits associated with adherence to CPAP therapy after 3 months of treatment? * Can a single motivational telephone intervention, one month after initiating CPAP therapy, significantly improve CPAP adherence at the three-month follow-up compared to no intervention? Researchers will compare patients who receive a phone call to those who do not, to see if this simple intervention leads to better CPAP adherence after three months of use. Participants will: * Undergo polysomnography before starting CPAP therapy, * Complete three questionnaires (IPIP50S, STAI, SEMSA) before starting CPAP therapy, * Be randomly assigned to either receive a motivational phone call one month after starting CPAP therapy or to a control group without any phone call, * Be invited for a follow-up after three months of CPAP use to download and analyze CPAP adherence data from their CPAP devices.