We do have randomised trials to support the argument, but (like most treatments) there's a very obvious dose-response curve. If we take outcome measures after e

We do have randomised trials to support the argument, but (like most treatments) there's a very obvious dose-response curve. If we take outcome measures after each therapy session, we can see that each additional therapy session has a diminishing marginal benefit. There's a reasonable argument that the most severely affected patients might gain clinically meaningful benefits from very small incremental gains, but that's very difficult to falsify because the effect size is so small. Long-term psychotherapy undoubtedly fails any reasonable cost-benefit test, but even setting that aside, I'd suggest that anyone who isn't satisfied with the results of therapy after 12-18 sessions would be better off trying something else - either a different therapist, a different psychotherapeutic modality, or a biomedical treatment. Anecdotally, the vast majority of people who I encounter who are in long-term psychotherapy aren't severely unwell; obviously that is in large part explained by the barriers to access faced by most severely unwell patients. Many of these people aren't "mentally ill" in any meaningful sense, exhibiting only subclinical symptoms of anxiety or depression even at the point of starting therapy. They don't have clear goals for therapy, or any real sense of when it would make sense for them to finish therapy. If they find therapy to be an enjoyable activity like doing yoga or having a massage then I have no qualms with that, but many of them ascribe benefits to long-term therapy that simply aren't supported by the evidence. https://pubmed.ncbi.nlm.nih.gov/30661486/ https://pubmed.ncbi.nlm.nih.gov/30661486/