Long-term effects of the Bergen 4-day treatment: a follow-up study
| ISRCTN | ISRCTN15432513 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN15432513 |
| Valtion tutkimusrahoitus (State's research funding) grant number | TYH2024337 |
| Sponsor | Helsinki University Hospital |
| Funder | Valtion tutkimusrahoitus |
- Submission date
- 28/04/2026
- Registration date
- 29/04/2026
- Last edited
- 28/04/2026
- Recruitment status
- Not yet recruiting
- Overall study status
- Ongoing
- Condition category
- Mental and Behavioural Disorders
Plain English summary of protocol
Background and study aims
Obsessive compulsive disorder (OCD) has ranked among 10 most debilitating disorders by WHO, affecting 2-3% of population, having early onset and substantial psychiatric comorbidity. Bergen 4 Day Treatment (B4DT) is a concentrated exposure treatment (cET) developed to treat OCD and has proven to be highly acceptable and effective. However, only a few studies have been conducted to assess the long-term effects of B4DT.
The aim of the study is to investigate the persistence of B4DT treatment results among the patients who have received B4DT in HUS in 2022-2026. In addition to OCD symptom severity, severity of depressive and anxiety symptoms, psychological distress and the overall functioning and wellbeing of the patients will be assessed.
Who can participate?
Adult patients aged 18 years and over who have received B4DT for their OCD in HUS in 2022-2026.
What does the study involve?
Participants will complete electronic questionnaires to measure their OCD, depressive and anxiety symptoms as well as psychological distress, overall wellbeing and functioning , and undergo a structured interview. Additional data such as information about participants' health care use and treatments will be collected from electronic health registry (EHR) data and HUS data pool.
What are the possible benefits and risks of participating?
Availability of effective evidence based treatments for OCD is very limited in Finland. This study aims to evaluate the implementation and long-term outcomes of this new form of effective treatment, B4DT. Participation or non-participation will have no impact on other treatment modalities or possibilities for the patients. The possible risks associated with interview and questionnaires included in this study are small. The interviewers are trained research assistants or psychologists with sufficient consultation support, and who are able to refer the interviewee to appropriate healthcare services if needed.
Where is the study run from?
The study will be conducted in Helsinki University Hospital (HUS), Finalnd.
When is the study starting and how long is it expected to run for?
The study is set to begin in May 2026, with recruitment, interviews and questionnaired expected to continue until the end of 2026
Who is funding the study?
The study is primarily funded by State’s research funding (Valtion tutkimusrahoitus). Additional funding
may be provided by HUS (Helsinki University Hospital) and other research foundations.
Who is the main contact?
Professor Suoma E. Saarni, MD, PhD, who serves as the principal investigator, is based at HUS and Tampere University, suoma.saarni@hus.fi
Contact information
Public, Scientific, Principal investigator
HUS Psychiatry, Välskärinkatu 12
Helsinki
00029
Finland
Helsinki
00029
Finland
 ORCID ID |
0000-0003-3555-9958 |
|---|---|
| Phone | +358407614711 |
| suoma.saarni@hus.fi |
Study information
| Primary study design | Observational |
|---|---|
| Observational study design | Case series |
| Scientific title | Bergen 4-day treatment (B4DT): A follow-up study about the persistence of the therapeutic effects after the intervention |
| Study acronym | B4Three |
| Study objectives | The aim of study is to investigate the persistence of B4DT treatment results among the patients who have received B4DT in HUS in 2022-2025. In addition to OCD symptom severity, severity of depressive and anxiety symptoms, the overall functioning and wellbeing of the patients (e.g. the employment status, absenteeism, social functioning) will be assessed. |
| Ethics approval(s) |
Approved 13/08/2025, Helsinki University Hospital (HUS) Regional Committee on Medical Research Ethics (PO BOX 705, Helsinki, 00029, Finland; +358 9471 71607; eettinen.toimikunta@hus.fi), ref: HUS/7582/2025 |
| Health condition(s) or problem(s) studied | Obsessive-Compulsive Disorder (OCD) |
| Intervention | Bergen 4 Day Treatment (B4DT) is a psychotherapeutic treatment based on intensive exposure and response prevention and targeted at OCD. All patients who have participated in B4DT for OCD in HUS in 2022-2025 will be contacted and offered an opportunity to participate in the study. Participants will complete electronic questionnaires to measure their OCD symptoms as well as overall mental wellbeing, and undergo a structured interview by a psychologist. Additional data, such as information about participants' psychiatric treatments, will be collected from electronic health registry (EHR) data and the HUS data pool. |
| Intervention type | Behavioural |
| Primary outcome measure(s) |
|
| Key secondary outcome measure(s) |
|
| Completion date | 31/12/2030 |
Eligibility
| Participant type(s) | |
|---|---|
| Age group | Mixed |
| Lower age limit | 18 Years |
| Upper age limit | 120 Years |
| Sex | All |
| Target sample size at registration | 75 |
| Key inclusion criteria | All patients that have participated in B4DT for OCD in HUS in Jan 2022-Dec 2025 will be contacted and offered an opportunity to participate in the study. |
| Key exclusion criteria | Not meeting the key inclusion criteria. |
| Date of first enrolment | 18/05/2026 |
| Date of final enrolment | 28/02/2027 |
Locations
Countries of recruitment
- Finland
Study participating centres
Results and Publications
| Individual participant data (IPD) Intention to share | No |
|---|---|
| IPD sharing plan summary | Not expected to be made available |
| IPD sharing plan |
Editorial Notes
28/04/2026: Study’s existence confirmed by the Helsinki University Hospital (HUS) Regional Medical Research Ethics Committee, Finland.
