Is intensive therapy evidence-based? What the research says
For trauma, there is evidence from several randomised trials that established therapies such as prolonged exposure, cognitive therapy and EMDR can be delivered intensively, over days or a few weeks, with results broadly similar to weekly treatment, and dropout has generally been low. For other methods, including Internal Family Systems and Brainspotting, there is not yet any research on intensive delivery, and the research on the methods themselves is at an early stage. Intensive therapy is a studied format, but whether a particular intensive is evidence-based depends on the method and the problem it is used for.
The short version
"Evidence-based" means that a treatment has been tested in well-designed studies, usually randomised trials, for a particular problem, and shown to help. Intensive therapy is a format, not a treatment in its own right, so the question has two parts. Does the method work? And does it still work when it is delivered in concentrated form?
For several trauma therapies, the answer to both is yes, based on randomised trials, although the number of trials is still small. For many other methods, including some commonly used in private intensives, one or both parts have not yet been tested.
Where the evidence is strongest: trauma therapies delivered intensively
Most of the research on intensives comes from trauma treatment. The therapies studied are mainly prolonged exposure, which involves repeatedly and carefully revisiting a traumatic memory and the situations it is linked to; cognitive therapies for PTSD; and EMDR. These were already well established as weekly treatments before researchers tested what happens when the sessions are moved closer together.
The main studies are summarised below.
| Study | Who took part | Format | Main finding |
|---|---|---|---|
| Ehlers et al., 2014 (UK, randomised trial) | 121 adults with chronic PTSD | Cognitive therapy over about 7 days, compared with the same therapy weekly over 3 months | 73% recovered from PTSD with the intensive format and 77% with weekly treatment. The intensive format reduced symptoms faster, with similar overall results |
| Foa et al., 2018 (US, randomised trial) | 370 active-duty military personnel | Prolonged exposure, 10 sessions over 2 weeks compared with 10 sessions over 8 weeks | The 2-week format was as effective as the 8-week format. The authors described the symptom reductions in all groups as relatively modest |
| Peterson et al., 2023 (US, randomised trial) | 234 military personnel and veterans | Two 3-week formats of prolonged exposure: one 90-minute session a day, or full days with additional components | Both reduced PTSD symptoms substantially. About half of each group no longer met the criteria for PTSD at six months |
| Van Woudenberg et al., 2018 (Netherlands) | 347 adults with severe PTSD and multiple traumas | 8 days of daily prolonged exposure and EMDR, with physical activity and education about trauma | 82.9% showed a clinically meaningful response and 54.9% no longer met the criteria for PTSD after treatment. Dropout was 2.3%. No comparison group |
| Hendriks et al., 2018 (Netherlands) | 73 adults with chronic PTSD after multiple traumas and several previous treatments | 12 sessions over 4 days, then 4 weekly sessions | 71% responded, with gains lasting to six months. Nobody dropped out of the intensive phase. No comparison group |
A 2020 systematic review brought together eleven studies of intensive formats of established trauma therapies. It found a large average reduction in PTSD symptoms and low dropout, between 0% and 13.6% across studies, with a pooled rate of about 5.5%.
Taken together, these studies support a clear but limited conclusion. For established trauma therapies, concentrating the sessions does not appear to weaken them, and it gets people to the same place sooner.
What the evidence does not show
The research is easy to overstate, so it is worth being precise about its limits.
Intensives are not consistently better than weekly therapy. In the randomised trials, the intensive and weekly formats produced broadly similar results. The main gain was speed, not size of effect.
Lower dropout is likely but not certain. Dropout in uncontrolled intensive programmes has often been very low. In the one large randomised trial that compared the same therapy over two weeks and over eight weeks, fewer people stopped treatment early in the two-week format, about 14% against about a quarter, but the authors reported that the difference was not statistically significant.
Not everyone improves. In the four-day study above, around three in ten participants did not respond. In the 2018 US trial, around four in ten of those randomised did not complete the full study. An intensive does not ensure change, and neither does weekly therapy.
Some studies had no comparison group. Large programmes with strong-looking results, such as the Dutch eight-day programme, did not randomise people to another treatment. Without a comparison, it is harder to know how much of the improvement was due to the treatment itself.
The research is mostly on PTSD. There is much less evidence on intensives for other difficulties, such as relationship problems, depression or anxiety that is not linked to trauma.
Do the effects last?
Several studies have followed people for six months or longer. In the 2023 US trial, the proportion of people no longer meeting the criteria for PTSD was much the same at six months as straight after treatment. On the clinician-rated measure, however, symptoms rose somewhat during follow-up in the lighter of the two formats, while the fuller format held its gains. In the Dutch eight-day programme, the participants followed up still had far fewer symptoms at six months than at the start, although clinician-rated symptoms had risen slightly since the end of treatment.
In these studies, gains from intensive trauma therapy largely held at six months, with some drift for some people. Few studies have followed people for longer than that. What happens after the intensive, including follow-up and support, is likely to matter, and is covered in more detail in the article on integration and aftercare.
Methods without intensive research: IFS and Brainspotting
Many private intensives, including some described on this site, use methods that have not been tested in intensive form.
Internal Family Systems. There are small pilot studies and trials of IFS, with positive findings in depression and in PTSD after childhood trauma. The IFS Institute describes this as an emerging evidence base and says that larger, replicated trials are needed before IFS can be called evidence-based for specific conditions. No study has tested IFS delivered as an intensive.
Brainspotting. The published research is mostly theoretical, with very few clinical studies. No study has tested Brainspotting delivered as an intensive.
The case for using these methods intensively rests on reasoning, not direct evidence. Some other trauma therapies have been shown to work in concentrated form, and the structure of these methods may suit longer sessions. That reasoning is plausible, but it is not the same as a trial, and it is better to say so than to borrow the evidence for other therapies.
Couples intensives
Research on couples intensives is limited. One study followed 118 heterosexual married couples who took part in an intensive form of Restoration Therapy, a couples approach drawing on attachment, mindfulness and emotion regulation. Couples reported greater marital satisfaction a month after the intensive, and this was sustained two years later. The study relied on self-report and had no comparison group.
How to read claims about intensives
When a provider describes intensives as evidence-based, these questions help to test the claim:
- Which method is being used, and has that method been tested for the problem I have?
- Has that method been tested in an intensive format, or is the evidence borrowed from other therapies?
- Were the studies randomised, and what were they compared with?
- Who took part, and how similar are they to me?
- How long were people followed up?
Common questions
Are intensives more effective than weekly therapy?
Not on average, according to the trials so far. The main finding is that, for the trauma therapies studied, intensive delivery works about as well as weekly delivery and gets there faster. Some studies suggest people are more likely to complete treatment in an intensive format, but this has not been consistent across trials.
Why is most of the research on PTSD?
Intensive formats were developed largely in trauma services, where long waiting lists and high dropout from weekly treatment were pressing problems. Concentrating treatment was studied as a way to address both. There is much less research on intensives for other difficulties.
Is there research on couples intensives?
A little. One study followed 118 married couples who took part in an intensive form of a couples therapy called Restoration Therapy, and found improved marital satisfaction a month afterwards that was sustained two years later. It relied on self-report and had no comparison group, so it is an encouraging early finding, not firm evidence.
What should I make of a provider who says intensives are proven?
Ask which method, for which problem, and which studies. A provider who can answer that precisely, and who can also tell you where the evidence runs out, is giving you a more trustworthy picture than one who cites research in general terms.
Lucy Orton's trauma intensives use Internal Family Systems and Brainspotting, with a pre-intensive workbook and session beforehand and a follow-up session afterwards. Suitability is discussed at a free consultation.
References
- Foa, E. B., McLean, C. P., Zang, Y., et al. (2018). Effect of prolonged exposure therapy delivered over 2 weeks vs 8 weeks vs present-centered therapy on PTSD symptom severity in military personnel: A randomized clinical trial. JAMA, 319(4), 354-364. doi:10.1001/jama.2017.21242
- Ehlers, A., Hackmann, A., Grey, N., Wild, J., Liness, S., Albert, I., Deale, A., Stott, R., & Clark, D. M. (2014). A randomized controlled trial of 7-day intensive and standard weekly cognitive therapy for PTSD and emotion-focused supportive therapy. American Journal of Psychiatry, 171(3), 294-304. doi:10.1176/appi.ajp.2013.13040552
- Peterson, A. L., Blount, T. H., Foa, E. B., et al. (2023). Massed vs intensive outpatient prolonged exposure for combat-related posttraumatic stress disorder: A randomized clinical trial. JAMA Network Open, 6(1), e2249422. doi:10.1001/jamanetworkopen.2022.49422
- Sciarrino, N. A., Warnecke, A. J., & Teng, E. J. (2020). A systematic review of intensive empirically supported treatments for posttraumatic stress disorder. Journal of Traumatic Stress, 33(4), 443-454. doi:10.1002/jts.22556
- Van Woudenberg, C., Voorendonk, E. M., Bongaerts, H., et al. (2018). Effectiveness of an intensive treatment programme combining prolonged exposure and eye movement desensitization and reprocessing for severe post-traumatic stress disorder. European Journal of Psychotraumatology, 9(1), 1487225. doi:10.1080/20008198.2018.1487225
- Hendriks, L., de Kleine, R. A., Broekman, T. G., Hendriks, G. J., & van Minnen, A. (2018). Intensive prolonged exposure therapy for chronic PTSD patients following multiple trauma and multiple treatment attempts. European Journal of Psychotraumatology, 9(1), 1425574. doi:10.1080/20008198.2018.1425574
- Ahlquist, L. R., & Hargrave, T. D. (2022). Effectiveness of Restoration Therapy in an intensive model. The Family Journal, 30(3), 301-306. doi:10.1177/10664807211052481
- IFS Institute. Internal Family Systems: An emerging evidence base, a strong foundation for more research. ifs-institute.com/resources/research
This page is general information about intensive therapy. It is not a substitute for individual assessment or advice, and reading it does not create a therapeutic relationship. If you are in crisis or at risk of harm, contact local emergency services or a crisis line now. How these articles are written and checked: our editorial standards.