Subgroup analyses of a concise trial of depressive and/or anxiety disorders

Rationale, aims and objectives: Concise forms of psychotherapy and psychopharmacotherapy have shown clinical effectiveness. Identifying the factors that predict who is most likely to benefit from such treatment may help to deliver the most adequate and person-centered care.

Methods: Secondary care outpatients aged 18-65 years with mild to moderate DSM-IV depressive and/or anxiety disorders, participated in a pragmatic randomized controlled equivalence trial comparing a concise format of cognitive behavioural and/or pharmacotherapy (i.e., concise care) to standard care. A range of putative factors associated with treatment outcome - socio-demographic characteristics and clinical characteristics - were assessed at baseline. Subgroup analyses were conducted analyzing the effects of interaction terms on changes over time in the Brief Symptom Inventory (BSI) scores as the outcome measure.

Results: A total of 182 participants were included and randomized to concise care (n = 93) and to standard care (n = 89). Participants were on average 36.5 (SD 12.3) years old and 61% were women. Patients suffering from any ‘anxiety (without depressive) disorder’ benefited significantly less from concise care than standard care (P = 0.012).

Conclusions: The benefit of a concise form of psychotherapy and pharmacotherapy was independent from demographic and clinical characteristics. Only patients with anxiety (without depressive) disorders benefit less from concise treatment.