Introduction: More than half of all patients seeking care for chest pain do not have a cardiac cause for this pain. Despite recurrent episodes of chest pain, many patients are discharged without a clear explanation of the cause for their pain. A lack of explanation may result in a misinterpretation of the pain as being cardiac-related, causing worry and uncertainty, which in turn leads to substantial use of healthcare resources. Psychological distress has been associated with non-cardiac chest pain (NCCP), but there is limited research regarding the relationship between different psychological factors and their association with healthcare utilization. There is a need for interventions to support patients to manage their chest pain, decrease psychological distress, and reduce healthcare utilization and costs. Aim: The overall aim of this thesis was to improve care for patients with non-cardiac chest pain by describing related psychological distress, healthcare utilization and societal costs, and by evaluating an Internet-delivered cognitive behavioural intervention. Designs and methods: This thesis presents results from four quantitative studies. Studies I and II had a longitudinal descriptive and comparative design. The studies used the same initial cohort. Patients were consecutively approached within 2 weeks from the day of discharge from a general hospital in southeast Sweden. In study I, 267 patients participated (131 with NCCP, 66 with acute myocardial infarction (AMI), and 70 with angina pectoris (AP)). Out of these, 199 patients (99 with NCCP, 51 with AMI, 49 with AP) participated in study II. Participants were predominantly male (about 60 %) with a mean age of 67 years. Data was collected on depressive symptoms (Study I), healthcare utilization (Study I, II), and societal costs (Study II). Study III had a cross-sectional explorative and descriptive design. Data was collected consecutively on depressive symptoms, cardiac anxiety and fear of body sensations in 552 patients discharged with diagnoses of NCCP (51 % women, mean age 64 years) from four hospitals in southeast Sweden. Patients were approached within one month from the day of discharge. Study IV was a pilot randomized controlled study including nine men and six women with a median age of 66 years, who were randomly assigned to an intervention (n=7) or control group (n=8). The intervention consisted of a four-session guided Internet-delivered cognitive behavioural therapy (CBT) program containing psychoeducation, exposure to physical activity, and relaxation. The control group received usual care. Data was collected on chest pain frequency, cardiac anxiety, fear of body sensations, and depressive symptoms. Results: Depressive symptoms were prevalent in 20 % (Study IV) and 25 % (Study I, III) of the patients, and more than half of the patients still experienced depressive symptoms one year later (Study I). There were no significant differences in prevalence and severity of depressive symptoms between patients diagnosed with NCCP, AMI or AP. Living a...