“During my training as a therapist, I learned that a good alliance between therapist and patient is the most important change mechanism of psychotherapy. But in practice I also use very specific techniques that I see working in patients. So which one is true? Or can they both be helpful at the same time?”
A good relationship is essential by definition
There is no doubt that the relationship between a patient and a therapist is important. Therapy can be defined as something that happens in the relationship between patient and therapist. That means the quality of that relationship is, by definition, an essential part of the therapy. If the relationship is not good, then the therapy is also not good.
It is less clear, however, whether the alliance is what actually causes the change in patients. That is because very little is known about how therapies work.
We know that therapies work. We do not know how.
Knowing that something works, but not how
To examine whether a therapy works, we can use a very strong scientific method: the randomized controlled trial. In such a study, a group of people with a mental health problem is split into two subgroups in a random way. One subgroup gets the treatment and the other does not, but otherwise the two groups are exactly the same. When the treatment ends and there are differences between the subgroups, these differences can logically only be caused by the treatment. This is the strongest design available in science to show that a therapy has caused change in a patient.
Examining how a therapy works is much more complicated, and the same strong research design cannot be used. Suppose that a therapy has been shown to be effective in reducing depression in a randomized trial, and we think that this may be caused by a reduction in negative thinking. We can look in the study at whether change in depression is associated with change in negative thinking. But even if we find such an association, that does not mean that the change in depression is caused by the change in negative thinking. It is just as possible that the change in negative thinking is caused by the improvement in depression. Or that a third factor, for example the alliance, causes both. There is no way to say with certainty which of these three possibilities is true.
This means that we do not know how therapies work, and we do not know whether the change is caused by the alliance, by specific techniques, or by something else entirely.
This is not a problem unique to psychotherapy
Psychotherapies are not an exception. It is also not known how antidepressants work. Even outside of medicine, we still do not know exactly how smoking causes cancer. We know that it causes cancer, and we know some of the mechanisms involved, but the precise process by which smoke enters the lungs, affects the body and leads to cancer is also not fully understood.
Knowing that something works, and knowing the exact mechanism by which it works, are two very different questions.
How researchers try to get a little more certainty
Even without a randomized trial of the mechanism itself, it is possible to gather evidence that makes one explanation more plausible than another. Researchers can examine, for example:
- Whether the change in the candidate mechanism (e.g. negative thinking) comes before the change in the outcome.
- Whether there is a dose-response association between the two: more change in the mechanism, more change in the outcome.
- Whether, among many variables measured in the same study, the candidate mechanism is the one most strongly associated with the outcome.
- Whether there is a clear theoretical framework explaining why specifically this factor should cause change.
- Whether laboratory or experimental studies support the association.
None of these elements on their own can prove causality, but together they can make a mechanism more or less likely.
So, what about the alliance?
There is much research showing that the alliance and positive outcomes are correlated. But as explained above, correlation is not enough to conclude that the alliance causes the change. There are also some studies showing that the alliance is already developing before the change in outcomes appears, which supports the hypothesis that it is a causal mechanism.
Overall, however, the evidence is still not strong enough to conclude that the alliance is itself a causal factor.
What this means for clinicians
What does this mean in practice? You should, of course, develop a good working relationship with every patient, because that is the core of what therapy is. The fact that science cannot say whether there is a causal association with the outcome does not change this in any way.
But it also means that you should apply the specific techniques of the therapy as well as possible, because these may also cause change. Assuming that both are essential is probably the best strategy.
Pim Cuijpers is professor emeritus of clinical psychology and scientific director of Metapsy. He has been involved in more than 1,100 scientific studies, mostly on psychological treatments of mental health problems. This is one of a series of evidence summaries in which Prof. Cuijpers tries to answer questions from patients and clinicians, based on what is known in science about treatments. The knowledge is mostly drawn from collective work of the Metapsy collaboration of at least 15 years. Do you have other questions you would like Prof. Cuijpers to discuss? Feel free to contact us.
Literature
- Cuijpers P, Reijnders M, Huibers MJH. (2019). The role of common factors in psychotherapy outcomes. Annual Review of Clinical Psychology, 15, 207–231.
- Flückiger C, Del Re AC, Wampold BE, Horvath AO. (2018). The alliance in adult psychotherapy: A meta-analytic synthesis. Psychotherapy, 55(4), 316–340.