Meta-analysis is a scientific term that refers to a structured review of a particular topic in the research literature. Meta-analyses look at a bunch of research studies that have been previously published, combine all their data (or look at all of their data in a systematic fashion), and come to some broad, general conclusions from the analysis.
Meta-analyses are helpful to researchers, clinicians and laypeople alike, because they help distill the entire research literature on a specific topic into an easily digested summary.
In this research update, we look at cognitive behavioral therapy (CBT) for childhood posttraumatic stress disorder (PTSD), effective treatments for depression in a mother surrounding the birth of her child, and a look at anxiety symptom prevention with cognitive-behavioral interventions.
The first meta-analysis (Kowalik et al., 2011) looks at the world of childhood post-traumatic stress disorder (PTSD). According to the researchers, there is no clear “gold standard treatment for childhood posttraumatic stress disorder (PTSD).”
An annotated bibliography and meta-analysis were used to examine the efficacy of cognitive behavioral therapy (CBT) in the treatment of pediatric PTSD as measured by outcome data from the Child Behavior Checklist (CBCL).
The efficacy of CBT in the treatment of pediatric PTSD was supported by the annotated bibliography and meta-analysis, contributing to best practices data. CBT addressed internalizing signs and symptoms (as measured by the CBCL) such as anxiety and depression more robustly than it did externalizing symptoms such as aggression and rule-breaking behavior, consistent with its purpose as a therapeutic intervention.
In other words, cognitive behavioral therapy works for the treatment of childhood PTSD. It seemed to works best for anxiety and depression related to PTSD, rather than for symptoms like rule-breaking or aggression.
Next up, we have a look at perinatal depression. Perinatal depression encompasses a wide range of mood disorders that can affect a woman during pregnancy and after the birth of her child. It includes prenatal depression, the “baby blues,” postpartum depression and postpartum psychosis. Between 15 and 20 percent of all women experience some form of pregnancy related depression or anxiety.
Sockol et al. (2011) conducted a meta-analysis to determine the efficacy of pharmacologic and psychological interventions for treatment of perinatal depression.
The researchers found 27 research studies that looked at these kinds of treatments for perinatal depression, including open drug trials (n=9), quasi-randomized trials (n=2), and randomized controlled trials (n=16) assessing change from pretreatment to posttreatment or comparing these interventions to a control group.
What did they find?
There was significant improvement in depressive symptoms from pretreatment to posttreatment, with an uncontrolled overall effect size (Hedges’ g) of 1.61 after removal of outliers and correction for publication bias. Symptom levels at posttreatment were below cutoff levels indicative of clinically significant symptoms.
At posttreatment, intervention groups demonstrated significantly greater reductions in depressive symptoms compared to control groups, with an overall controlled effect size (Hedges’ g) of 0.65 after removal of outliers.
What was most effective? Well, the researchers found that individual psychotherapy was superior to group psychotherapy. In this meta-analysis, the researchers found that psychotherapy focused on interpersonal therapy interventions was more effective than interventions focused on cognitive-behavioral interventions.
Finally, we look at whether cognitive-behavioral therapy (CBT) helps in the prevention of anxiety symptoms. Zalta (2011) conducted a systematic review that identified 15 independent pretest-posttest randomized or quasi-randomized efficacy trials for analysis.
At posttest (the end of the research study), groups which had CBT treatment demonstrated significantly greater symptom reduction compared to control groups. (The researcher reported weighted mean effect sizes (Hedges’ g) of 0.25 for general anxiety, 0.24 for disorder-specific symptoms, and 0.22 for depression after the removal of outliers.)
But for some reason, the effects didn’t seem to last. They appeared to diminish over 6- and 12-month follow-up.
Further analyses indicated that individually administered media interventions were more effective than human-administered group interventions at preventing general anxiety and depression symptoms.
Kowalik J, Weller J, Venter J, Drachman D. (2011). Cognitive behavioral therapy for the treatment of pediatric posttraumatic stress disorder: a review and meta-analysis. J Behav Ther Exp Psychiatry, 42, 405-13.
Sockol, L.E., Epperson, C.N., Barber, J.P. (2011). A meta-analysis of treatments for perinatal depression. Clin Psychol Rev, 31, 839-49. doi: 10.1016/j.cpr.2011.03.009.
Zalta, A.K. (2011). A meta-analysis of anxiety symptom prevention with cognitive-behavioral interventions. J Anxiety Disord, 25, 749-60.