Meta-analysis of the influence of age on symptom change following cognitive-behavioural treatment for anxiety disorders

Introduction: Adolescents, relative to adults, show impairments in learning to reduce or extinguish fear. Furthermore, they may struggle with the use of reappraisal techniques to regulate affect. Both learning and reappraisals are critical to cognitive-behavioural treatments (CBT) for anxiety disorders leading to the hypothesis that adolescents may respond more poorly to CBT than adults. Methods: We use meta-regression to explore whether variability in the mean age of participants in trials of CBT for anxiety predicted variability between studies in symptom change effect sizes. PsycARTICLES, PsycINFO, MEDLINE and Embase databases were searched with the terms exposure and each of anxiety, phobia, or panic disorder diagnostic terms and cognitive behav* therapy with each of the diagnostic terms. Data were pooled from CBT trials for anxiety disorders (excluding anxiety-related disorders – obsessive compulsive disorder and posttraumatic stress disorder) where participants’ mean age was 11 years or older. 149 studies were selected and data on change in symptoms from pre-treatment to post-treatment (k = 195), pre-treatment to follow-up (k = 108) and post-treatment to follow-up (k = 107) were extracted. Results: Several possible confounding variables were also accounted for (e.g., proportion of females, number of sessions). Younger age was associated with smaller improvement in anxious symptoms from pre-to post-treatment. However, younger age was also associated with greater improvement in symptoms from post-treatment to follow-up. Conclusions: CBT is effective at reducing anxious symptoms, however, younger people may respond more slowly to treatment than older people.