have consistently demonstrated that there are no substantial differences in outcomes among treatments". The handbook states that there is "little evidence to suggest that any one psychological therapy consistently outperforms any other for any specific psychological disorders. This is sometimes called the Dodo bird verdict after a scene/section in Alice in Wonderland where every competitor in a race was called a winner and is given prizes". Further analyses seek to identify the factors that the psychotherapies have in common that seem to account for this, known as common factors theory; for example the quality of the therapeutic relationship, interpretation of problem, and the confrontation of painful emotions. Outcome studies have been critiqued for being too removed from real-world practice in that they use carefully selected therapists who have been extensively trained and monitored, and patients who may be non-representative of typical patients by virtue of strict inclusionary/exclusionary criteria. Such concerns impact the replication of research results and the ability to generalize from them to practicing therapists. However, specific therapies have been tested for use with specific disorders, and regulatory organizations in both the UK and US make recommendations for different conditions. The Helsinki Psychotherapy Study was one of several large long-term clinical trials of psychotherapies that have taken place. Anxious and depressed patients in two short-term therapies (solution-focused and brief psychodynamic) improved faster, but five years long-term psychotherapy and psychoanalysis gave greater benefits. Several patient and therapist factors appear to predict suitability for different psychotherapies. Meta-analyses have established that cognitive behavioural therapy (CBT) and psychodynamic psychotherapy are equally effective in treating depression. A 2014 meta analysis over 11,000 patients reveals that Interpersonal Psychotherapy (IPT) is of comparable effectiveness to CBT for depression but is inferior to the latter for eating disorders. For children and adolescents, interpersonal psychotherapy and CBT are the best methods according to a 2014 meta analysis of almost 4000 patients. Mechanisms of change It is not yet understood how psychotherapies can succeed in treating mental illnesses. Different therapeutic approaches may be associated with particular theories about what needs to change in a person for a successful therapeutic outcome. In general, processes of emotional arousal and memory have long been held to play an important role. One theory combining these aspects proposes that permanent change occurs to the extent that the neuropsychological mechanism of memory reconsolidation is triggered and is able to incorporate new emotional experiences. Adherence Patient