Evidence
What the research actually shows
The findings that unsettle every school equally: equivalence between bona fide treatments, the size of therapist effects, the alliance, deterioration, and how to read a trial without being persuaded by it.
8 topics
Method
ESTs, evidence-based practice, and practice-based evidence
Three terms that are routinely confused, and the arguments each one is used to win.
How to read a psychotherapy trial
The six questions that determine what a result means.
Effect sizes and clinical significance
What the numbers mean, and how they are made to mean more than they do.
What works, and through what
Common factors and the contextual model
The finding that unsettles every school equally, and what it does not establish.
The therapeutic alliance
The most replicated process finding in the field, and the causal question it has not settled.
Therapist effects and deliberate practice
Who delivers the treatment matters more than which treatment it is — and experience does not fix it.
What goes wrong
Evidence by system
Every system carries its own evidence summary, with the comparator and the limits stated.
| System | Status | Best supported for |
|---|---|---|
| Psychoanalytic Therapies | good | Personality disorders, especially borderline (TFP, MBT); Depression, including chronic and recurrent forms |
| Psychodynamic Therapies | good | Depression, including recurrent and chronic presentations; Borderline personality disorder (MBT, TFP) |
| Adlerian Therapy (Individual Psychology) | limited | Parenting and family difficulties; Discouragement and low self-esteem |
| Analytical Psychology (Jungian) | limited | Midlife transition, meaning and existential concerns; Clients drawn to symbolic and imaginal work |
| Object Relations Theory | mixed | Personality disorders, through TFP and MBT; Complex, long-standing relational difficulties |
| Self Psychology | limited | Narcissistic personality difficulties; Chronic emptiness and depletion |
| Relational Psychoanalysis | mixed | Patients whose difficulties are enacted rather than reported; Repeated treatment failures and ruptures with previous therapists |
| Mentalization-Based Treatment | good | Borderline personality disorder; Self-harm in adolescents |
| Transference-Focused Psychotherapy | good | Borderline personality organisation; Narcissistic pathology at the borderline level |
| Intensive Short-Term Dynamic Psychotherapy | good | Somatic symptom and medically unexplained disorders; Treatment-resistant depression and anxiety |
| Existential Therapies | mixed | Distress in life-limiting and terminal illness; Bereavement and loss |
| Person-Centered Therapies | good | Depression, particularly where relational and self-worth themes predominate; Adjustment difficulties, life transitions and bereavement |
| Motivational Interviewing | strong | Alcohol and substance use; Ambivalence about any specific behaviour change |
| Gestalt Therapy | promising | Unresolved anger and grief toward significant others; Internal conflict and self-criticism |
| Emotion-Focused Therapy | good | Depression, particularly with self-criticism or unresolved relational injury; Couple distress (EFT-C) |
| Interpersonal Theory & Reconstructive Therapy | good | Chronic and treatment-resistant depression (CBASP); Longstanding interpersonal difficulties |
| Interpersonal Psychotherapy | strong | Major depressive disorder, acute and maintenance; Perinatal and postnatal depression |
| Exposure Therapies | strong | Specific phobia; Panic disorder and agoraphobia |
| Behavior Therapies | strong | Depression (behavioural activation); Anxiety disorders and OCD (exposure-based) |
| Eye Movement Desensitisation and Reprocessing | strong | PTSD, including single-incident and combat trauma; Traumatic grief |
| Cognitive Therapy | strong | Major depression, including as a relapse-prevention strategy; Panic disorder, social anxiety, GAD, specific phobia |
| Rational Emotive Behavior Therapy | good | Anxiety and depression; Anger problems |
| Schema Therapy | good | Borderline and other personality disorders; Chronic depression |
| Metacognitive Therapy | good | Generalised anxiety disorder; Depression with prominent rumination |
| Acceptance and Commitment Therapy | good | Chronic pain and long-term physical conditions; Depression |
| Dialectical Behavior Therapy | strong | Borderline personality disorder; Chronic suicidal and self-harming behaviour |
| Compassion-Focused Therapy | promising | High shame and self-criticism; Depression with prominent self-attack |
| Mindfulness-Based Cognitive Therapy | strong | Preventing depressive relapse in recurrent depression, especially with three or more episodes; Residual depressive symptoms |
| Systemic & Family Therapies | good | Adolescent anorexia nervosa (family-based treatment); Relapse prevention in schizophrenia (family psychoeducation) |
| Couple Therapies | good | Couple distress and relationship dissatisfaction; Depression in the context of relationship distress |
| Gender-Informed Therapies | mixed | Minority stress in LGBTQ+ clients; Recovery from sexual violence and intimate partner violence |
| Multicultural Therapies | good | Engagement and retention of clients from minoritised groups; Alliance formation across difference |
| Positive Psychology & Well-Being Therapies | promising | Relapse prevention after acute treatment for depression (WBT); Residual symptoms and anhedonia |
| Solution-Focused Brief Therapy | promising | Clients with a clear goal and reasonable resources; Child, family and school-based problems |
| Narrative Therapy | limited | Problems saturated with shame and identity; Children and families |
| Personal Construct Psychology | limited | Clients who respond to an experimental, collaborative frame; Identity and meaning difficulties |
| Integrative Therapies | good | Complex and comorbid presentations; Patients who have not responded to a single-model treatment |
| The Unified Protocol | good | Comorbid anxiety and depression; Panic, social anxiety, GAD |
| Group Psychotherapy | strong | Depression and anxiety; Social anxiety, where the format is itself exposure |
| Somatic & Body-Oriented Therapies | promising | Arousal dysregulation as an adjunct; Patients who cannot tolerate narrative trauma work |
| Clinical Hypnosis & Hypnotherapy | good | Irritable bowel syndrome; Procedural and chronic pain |
| Psychedelic-Assisted Psychotherapy | promising | Psychological distress in life-threatening illness; Treatment-resistant depression (phase 2 evidence, phase 3 ongoing) |
| MDMA-Assisted Psychotherapy | controversial | Severe, chronic PTSD unresponsive to established treatments — on phase 3 evidence that has not satisfied a regulator |
| Ketamine-Assisted Psychotherapy | mixed | Treatment-resistant depression, short-term; Acute suicidal ideation, short-term |
| Digital & Low-Intensity Therapies | strong | Mild to moderate depression and anxiety; Insomnia — digital CBT-I is particularly well supported |