Overcoming the difficulties of meta-analysis in psychotherapy




Poster session 1


Sunday 16 September 2018 - 12:30 to 14:00

All authors in correct order:

Lopez PL1, Ciapponi A2
1 Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro University and CONICET, Argentina
2 Institute for Clinical Effectiveness and Health Policy (IECS-CONICET), Argentina
Presenting author and contact person

Presenting author:

Pablo Luis Lopez

Contact person:

Abstract text
Although the number of systematic reviews (SRs) and meta-analysis (MAs) that evaluate the efficacy of psychotherapy has increased in recent years, the evidence is still scarce compared to studies of medical treatments. This limitation could be explained by the low number of randomized controlled trials and lack of knowledge about methodology. Additionally, psychotherapy presents particularities that hinder MAs with standard proceedings like high heterogeneity of assessment tools, or different modalities of treatments with the same denomination but different components and session frequencies.

To evaluate the trends in SRs/MAs in psychotherapy in the Cochrane Library compared to PubMed and to assess the frequency of considerable heterogeneity in primary outcomes of a sample of recent Cochrane Reviews. We will discuss alternative proceeding adapted to the heterogeneity of the SRs/MAs.

We reviewed publications of SRs/MAs about psychotherapy in PubMed and the Cochrane Library from the last 10 years and heterogeneity issues in Cochrane MAs in the last year.

From 27 February 2018 there were 557 results from 10219 records (5%) when we searched on 'psychotherapy' in Cochrane Reviews and 4927 SRs or MAs (filtered by publication type) in PubMed. In the last 10 years SRs/MAs in PubMed and the Cochrane Library showed divergent trends: +37 yearly (95% confidence interval (CI) 30 to 45; P < 0.0001) and -3 yearly (95% CI -5 to -2; P = 0.002) respectively (Figure 1).
We found that 20/27 (74%) of Cochrane Reviews published in 2017 which specifically involved psychotherapy, presented considerable heterogeneity (I2 > 60%) in the primary outcomes.

Cochrane MAs in psychotherapy do not follow the growing up trend. Heterogeneity of outcome measures is a common problem. It is necessary that psychologists promote a consensus about the assessment tools and treatment modalities to facilitate and increase MAs and to reduce the heterogeneity.
Also, the standards and requirements from Cochrane editorial boards would need to be rethought to consider the complexity of psychotherapy research.

Patient or healthcare consumer involvement:


Relevance to patients and consumers: 

The information about the efficacy of the psychological treatments is scarce. In clinical practice, patients increasingly request information about the modalities of psychotherapy to be able to choose the best treatment and it is a duty of psychologists to provide reliable information on this subject. The access to clinical trials are limited and the percentage of meta-analysis on psychotherapy is much lower than that of medical treatments. We think that one of the main reasons that explain this lack of evidence is are the difficulties to meta-analyse psychological treatments due to the heterogeneity of measures and treatment modalities.