Looking for therapy means encountering an alphabet of acronyms and a set of confident claims about which approach works for what.

The evidence supports a more nuanced picture, and understanding it makes choosing considerably less bewildering.

The approaches with substantial evidence

Cognitive behavioural therapy. The largest evidence base of any psychotherapy, with trials across depression, anxiety disorders, obsessive-compulsive disorder, post-traumatic stress, insomnia and more. Structured, time-limited, focused on the relationship between thoughts, behaviours and feelings.

The volume of evidence partly reflects that CBT is easy to manualise and therefore to study, which is worth bearing in mind when comparing evidence bases.

Behavioural activation. A simpler approach focused on increasing engagement with rewarding activity. Trials have found it comparable to fuller CBT for depression, which is notable given it requires less training to deliver.

Interpersonal therapy. Time-limited, focused on relationships and social roles. Good evidence for depression.

Exposure-based therapies. The core evidence-based treatment for anxiety disorders and phobias, involving graded confrontation of feared situations. Highly effective and underused, partly because it's demanding for both parties.

EMDR. Recommended in several guidelines for post-traumatic stress with substantial trial evidence. There's ongoing debate about whether the eye movement component adds anything beyond the exposure element, and the treatment as a whole works.

Dialectical behaviour therapy. Developed for borderline personality disorder and self-harm, with good evidence in that population.

Acceptance and commitment therapy and other third-wave approaches. Growing evidence base, generally comparable outcomes to CBT in head-to-head trials.

Psychodynamic therapy. A smaller but real evidence base, with trials finding benefits for depression and some other conditions. Historically under-studied relative to its use, partly because it's harder to manualise.

The equivalence finding

The most consistent result in psychotherapy research, and the most surprising to people outside the field.

When established therapies with a coherent rationale are compared directly, differences in outcome are frequently small or absent. This has been observed repeatedly across decades, and is sometimes called the dodo bird verdict.

It's contested. Some argue that differences do exist for specific conditions — exposure for anxiety disorders being the clearest case — and that averaging across conditions obscures them.

The moderate reading is that for common conditions like depression, several approaches work comparably well, while for some specific presentations particular approaches have a genuine advantage.

What predicts outcome

If modality matters less than expected, what matters more?

The therapeutic alliance. The quality of the relationship between therapist and client is among the most consistent predictors of outcome across approaches. Feeling understood, agreeing on goals, and trusting the process.

Client factors. Expectations, motivation and external circumstances account for a substantial share of variance.

Therapist effects. Individual therapists differ measurably in their outcomes, within the same modality. Some are consistently more effective than others, and the reasons aren't well characterised.

Actually doing it. Attendance and engagement with between-session work predict outcome. This sounds obvious and it's the main mechanism by which treatment fails.

The practical implication: finding a therapist you can work with matters more than finding the theoretically correct modality, within the range of approaches that have evidence.

What to be cautious about

Some things worth knowing.

Approaches with no controlled evidence, however confident the claims. There are a great many named therapies and most have never been tested.

Anything promising rapid resolution of complex problems, or claiming effectiveness for everything.

Recovered memory techniques, which have a documented history of generating false memories and considerable harm.

Practitioners without recognised qualification or professional registration. Titles are unprotected in many jurisdictions, and checking registration with a professional body is worth doing.

Practical guidance

If you have a specific condition with a specific recommended treatment — post-traumatic stress, obsessive-compulsive disorder, a phobia — seek someone trained in that treatment. The specificity matters most in these cases.

For more general difficulties, choose based on fit and practicality. An approach you'll engage with, delivered by someone you can talk to, at a frequency you can sustain.

Ask about training and about how the therapist works. A good practitioner will answer straightforwardly.

Give it a reasonable trial — several sessions — and if the alliance isn't developing, say so. That conversation is itself therapeutic material, and if it doesn't help, changing therapist is a legitimate decision rather than a failure.

And know that self-guided and digital versions of evidence-based approaches exist and have their own supporting trials, which matters where access or cost is a barrier.

General information only. If you are struggling with your mental health, please contact a qualified professional. If you are in crisis, contact emergency services or a crisis helpline in your country.

Access and the alternatives

Worth acknowledging the practical reality, since availability shapes what most people can actually do. Waiting lists for publicly funded therapy are long in many health systems, and private provision is unaffordable for a great many people.

Several options have evidence and lower barriers. Guided self-help based on cognitive behavioural principles has trial support, particularly for mild to moderate depression and anxiety. Digital programmes based on the same approaches have their own supporting evidence, with the caveat that adherence is generally better when there is some human contact involved.

Group therapy is frequently more available than individual and has comparable evidence for several conditions. And for some people, structured peer support has genuine value, though the evidence base is thinner.

None of these replaces individual therapy for complex or severe presentations. They are considerably better than an unfilled year on a waiting list.