Blog
The Psychotherapy Practice Research Network (PPRNet) blog began in 2013 in response to psychotherapy clinicians, researchers, and educators who expressed interest in receiving regular information about current practice-oriented psychotherapy research. It offers a monthly summary of two or three published psychotherapy research articles. Each summary is authored by Dr. Tasca and highlights practice implications of selected articles. Past blogs are available in the archives. This content is only available in English.
This month...

…I blog about the treatment of depression, the effects of role induction in psychotherapy, and negative experiences in psychotherapy from clients’ perspective.
Type of Research
Topics
- ALL Topics (clear)
- Adherance
- Alliance and Therapeutic Relationship
- Anxiety Disorders
- Attachment
- Attendance, Attrition, and Drop-Out
- Client Factors
- Client Preferences
- Cognitive Therapy (CT) and Cognitive-Behavioural Therapy (CBT)
- Combination Therapy
- Common Factors
- Cost-effectiveness
- Depression and Depressive Symptoms
- Efficacy of Treatments
- Empathy
- Feedback and Progress Monitoring
- Group Psychotherapy
- Illness and Medical Comorbidities
- Interpersonal Psychotherapy (IPT)
- Long-term Outcomes
- Medications/Pharmacotherapy
- Miscellaneous
- Neuroscience and Brain
- Outcomes and Deterioration
- Personality Disorders
- Placebo Effect
- Practice-Based Research and Practice Research Networks
- Psychodynamic Therapy (PDT)
- Resistance and Reactance
- Self-Reflection and Awareness
- Suicide and Crisis Intervention
- Termination
- Therapist Factors
- Training
- Transference and Countertransference
- Trauma and/or PTSD
- Treatment Length and Frequency
August 2013
How Much Psychotherapy Is Necessary?
Handbook of Psychotherapy and Behavior Change: Starting in March 2013 I will review one chapter a month in the Handbook of Psychotherapy and Behavior Change in addition to reviewing psychotherapy research articles. Book chapters have more restrictive copy right rules than journal articles, so I will not provide author email addresses. If you are interested, the Handbook table of content can be viewed on Amazon.
Lambert, M.J. (2013). The efficacy and effectiveness of psychotherapy. In M.J. Lambert (Ed.) Bergin and Garfield’s handbook of psychotherapy and behaviour change (6th ed.), pp. 169-218. Hoboken, N.J.: Wiley.
An important issue for patients, therapists, and agencies is the optimal dosage of psychotherapy that is necessary to reduce impairment and improve life functioning. In this part of the Handbook chapter on Efficacy and Effectiveness of Psychotherapy, Lambert tackles the issue of the psychotherapy dose-response relationship by reviewing the existing literature. That literature tends to focus on naturalistic national (U.S.) samples of patients (often N > 6,000) receiving routine care in Health Maintenance Organizations, Employee Assistance Programs, and Community Mental Health Clinics. Outcomes tend to be assessed by patient self report, and can include symptoms, character traits, quality of life, and interpersonal functioning, among others. Lambert defines “improved” patients as those who reliably changed but still are within the dysfunctional range on a measure, and he defines “recovered” patients as those who both reliably improved and were no longer in the dysfunctional range. He concluded that on average 50% of patients who begin treatment in the dysfunctional range achieve recovery following 21 sessions of psychotherapy. On the flip side, half of patients do not achieve recovery after 21 sessions. Almost 50 sessions are necessary for 75% of patients to recover. In other words, there is a rapid rate of recovery in which half of patients recover after 21 sessions, but then the rate of recovery slows down so that it takes up to 50 sessions for an additional 25% of patients to recover. The rates of recovery also differ depending on what is measured. Symptoms (depression, anxiety, etc.) tend to recover more quickly than characterological or interpersonal problems. Further, some patients experience sudden symptom gains in therapy that are long lasting. Between 17% and 50% of patients experience the majority of their symptom improvements within 7 sessions, and these early changes accounted for 50% of total symptom gains in therapy.
Practice Implications
The question of how much therapy is enough is important for practical and theoretical reasons. Research on this topic can help patients, therapists, and agencies make decisions about treatment planning. Research suggests that a sizeable proportion of patients (50%) reliably improve after 7 sessions and a similar percentage recover after 21 sessions. However, limiting treatment to less than 20 sessions will mean that about half of patients will not achieve a substantial benefit from therapy. Session limits need to be assessed carefully depending on how the patient is doing and what outcomes are important or valued. Agencies or clinicians that firmly set limits on the number of psychotherapy sessions that are too low will have the majority of their patients showing some improvement but not recovering.