Heterogeneity of treatment effects in trials on psychotherapy of depression

Abstract

BackgroundPsychotherapy is an evidence-based treatment for depression, but its average effect is modest. Thus, identifying subgroups that respond especially well to psychotherapy is an important goal. This would allow maximizing the efficacy of interventions. However, the extent of treatment effect heterogeneity (TEH) has not yet been systematically investigated. A reliable, evidence-based estimate of this heterogeneity would allow a more accurate assessment of the potential effects of enhancement by personalization.MethodsUsing a large database of randomized-controlled trials on psychotherapy for depression in adults (k = 306), we performed a Bayesian variance ratio meta-regression. Based on the results, we determined the theoretically maximum possible extent of variability of individual outcomes. Exploratory subgroup analyses were conducted for different types of psychotherapy. We determined the extent of expected TEH given the evidence by employing an analytical approach.OutcomesWe found for the entire sample a 9% higher variance in the intervention groups compared to the control groups, indicating TEH in psychotherapy for depression. Depending on the depression scale used, this corresponds to a standard deviation of the individual treatment effect of 3-4 points. Subgroup analyses revealed that due to a large number of studies, the evidence for TEH is strongest in cognitive-behavioural therapy, while the largest TEH was observed in behavioural activation therapy.InterpretationOur results show that the treatment effect of psychotherapy for depression varies. This is a clear indication that patients benefit differently from different interventions. Clinical or statistical methods that select the optimal intervention for each patient are likely to increase the success of treatment.

Mechanistic pathways of change in twice weekly versus once weekly sessions of psychotherapy for depression

“…While working memory did not moderate the relation between session frequency and change in the therapy processes, working memory was correlated with change in CBT and IPT skills. This latter finding is in line with earlier results showing that working memory plays a role in predicting the success of psychotherapy (Bruijniks, Sijbrandij, & Huibers, 2019), but also with recent studies that emphasize that interventions work differently for subgroups of patients (Huibers et al, 2021;Kaiser, Volkmann, Volkmann, Karyotaki, & Cuijpers, 2020). In addition, this finding may suggest that the role of baseline working memory might be specific for the therapy processes that seem to rely mostly on cognitive functioning since the acquisition of skills is a highly cognitive process (Tenison & Anderson, 2017;VanLehn, 1996) that not only needs to be activated during treatment, but also involves practice within sessions.…”

Is it worth it to personalize the treatment of PTSD? – A variance-ratio meta-analysis and estimation of treatment effect heterogeneity in RCTs of PTSD

“…Regarding the psychopharmacological treatment for mental disorders, differences in individual treatment responses have already been evaluated for antipsychotics in the treatment of schizophrenia (Winkelbeiner et al, 2019) and antidepressants in the treatment of depression (Plöderl & Hengartner, 2019), both indicating no evidence for TEH. However, the first VR meta-analysis concerning TEH in psychological treatments for adult depression yielded promising findings with an outcome variance that is 9% larger in treatment groups compared to control groups (Kaiser et al, 2020). The evidence of TEH in psychological treatments for depression highlights that estimating the extent of TEH might be a promising avenue to researchers developing tailored approaches in psychotherapy and practitioners who apply them, as it allows to assess whether personalization of psychotherapy is at all useful and what effects a possible personalization of psychological treatments can achieve.…”

Is it worth it to personalize the treatment of PTSD? - A variance-ratio meta-analysis and estimation of treatment effect heterogeneity in RCTs of PTSD

“…For an overview of this field, we refer to specific literature (Riley et al, 2021). Second, the variability of our estimate of TEH THIS IS A PRE-PRINT THAT HAS NOT BEEN PEER-REVIEWED 12 (as indicated by the SD of the intercept) was high and exceeded those of a similar study for depression (Kaiser et al, 2020), suggesting unexplained between-study variance. This finding might be traced back to differences in study designs (e.g., session frequency, exclusion and inclusion criteria, diagnostic criteria and comorbidities) across studies.…”