Taking a transdiagnostic treatment approach is only one of a number of options availableto clinicians in routine clinical practice who face the daily challenge of addressing anxiety and depression in their patients in the absence of research data and guidelines to inform their deci- sion-making. Despite the merit of such approaches and interest in them, the quality of existing research studies is relatively poor and certainly lags behind those evaluating disorder-specific approaches in which many clinicians will have been trained [3].Alternative approaches to the problem of comorbidity are to use evidence based disorder- specific interventions to (i) focus on the treatment of one of the disorders and measure the out- comes in both, or (ii) address both disorders simultaneously, sequentially or alternating between them. There are relatively little data on each of these treatment options. One relevant study is that of Craske and colleagues in which sixty-five patients with panic disorder and a comorbid anxiety disorder were randomly assigned to CBT focused solely upon panic disorder or CBT that simultaneously addressed panic disorder and the most severe comorbid condition [11]. Results indicated that those receiving CBT focused only on panic disorder were more likely to meet high end-state functioning at post-treatment and zero panic attacks at the one- year follow-up. It was concluded that remaining focused on CBT for panic disorder may be a better treatment option both for the primary and comorbid diagnoses than combining CBTfor multiple disorders.A similar finding, that it is better to stay focused onone disorder rather than addressing mul- tiple disorders, was obtained by Gibbons and deRubeis [12]. In this study, 24 patients with both anxiety and depression participating in a CBT for depression trial were found to have a worse outcome for both depression and anxiety if the therapist addressed both disorders rather thanremaining focused on depression. There is a paucity of other studies directly speaking to this important issue but for patients with major depressive disorder, it does not appear that broader, arguably complex cognitive therapy is superior to the more focused intervention of behavioural activation [13] and behavioural activation may even have advantages in severe cases [14].