Guidelines recommend screening for psychiatric co-morbidities in patients with congenital heart defects alongside cardiac outpatient follow-ups. These recommendations are not implemented in Denmark. This study aimed to investigate the psychiatric co-morbidities in children and adolescents with Fontan circulation in Denmark and to evaluate the feasibility of an online screening measure for psychiatric disorders.

Children, adolescents, and their families answered the Development and Well-Being Assessment questionnaire and a questionnaire about received help online. Development and Well-Being Assessment ratings present psychiatric diagnoses in accordance with ICD-10 and DSM-5. Parent-reported received psychiatric help is also presented. Feasibility data are reported as participation rate (completed Development and Well-Being Assessments) and parental/adolescent acceptability from the feasibility questionnaire.

The participation rate was 27%. Of the participating children and adolescents, 53% (ICD-10)/59% (DSM-5) met full diagnostic criteria for at least one psychiatric diagnosis. Of these, 50% had not received any psychiatric or psychological help. Only 12% of participants had an a priori psychiatric diagnosis.

We found that a large proportion of children and adolescents with Fontan circulation are underdiagnosed and undertreated for psychiatric disorders. The results from our study emphasise the need for psychiatric screening in this patient group. Development and Well-Being Assessment may be too comprehensive for online electronic screening in children and adolescents with CHD.