Short summary

Psychotherapy is a non-pharmacological treatment procedure, which is associated with fewer and milder side effects compared to pharmacotherapy. The purpose of the study is to investigate the nationwide use of psychotherapy treatment among Danish individuals assigned with a psychiatric disorder diagnosis within the last two decades and to validate the psychotherapy procedure code registered in the Danish register.

Rationale

Individuals assigned with a psychiatric disorder are characterized by a higher mortality rate than the average population and side effects to pharmacological treatment are one of various factors that contribute to this increased risk. Non-pharmacological treatment like psychotherapy is associated with less side effects than pharmacological treatment and in Denmark it is recommended first-line treatment towards common psychiatric disorders, such as unipolar depression, anxiety and obsessive-compulsive disorder (OCD) in children, adolescents and adults. The aims of the study are to 1) investigate the nationwide use of psychotherapy treatment among Danish individuals assigned with a psychiatric disorder diagnosis during the study period 1 January 2001 to 31 December 2020 and 2) to assess the validity of the psychotherapy procedure code registered in the Danish National Patient Registry.

Description of the cohort

All Danish individuals aged ≥ 3 years, who were registered with 1) a psychiatric disorder diagnosis (F10-F99) or 2) had a psychotherapy treatment session (procedure code BRSP1/3/5) during the study period 1 January 2001 to 31 December 2020. Within this cohort of individuals, who was provided with psychotherapy, a random sampling (N = 1,000) was conducted in order to characterize and validate the psychotherapy treatment session offered.

Data and biological material

Identification of all Danish individuals assigned with a psychiatric disorder diagnosis and information regarding psychotherapeutic treatment were retrieved from The Danish National Patient Registry. Validation and characterization of the psychotherapy treatment offered was done by data extraction from 1,000 patient hospital records.

Collaborating researchers and departments

Clinical Pharmacology, Pharmacy and Environmental Medicine, Department of Public Health, University of Southern Denmark, Denmark

• PhD, postdoc, Lotte Rasmussen
• Data manager, Martin Thomsen Ernst
• PhD, associate professor, staff specialist, Rikke Wesselhøft