CBT has repeatedly been shown to have a lasting effect in the treatment of depression. Meta-analyses of 48 randomized controlled trials have shown that Cognitive Therapy (CT) is effective in treating mild to moderate depression (Gloaguen, Cottraux, Cucherat, & Blackburn, 1997). Research has demonstrated that CBT is superior to anti-depressant treatment and can be used as an alternative or adjunctive to pharmacological therapy. Combination therapy (medication plus CBT) is beneficial for cases of chronic and severe depression (Parker, Roy, and Eyers, 2003). For those who cannot tolerate medicine, have medication-resistant depressive disorders, or children and adolescents for whom early prescribing poses concerns, CBT is shown to be a particularly effective and preventative treatment (Parker et al., 2003).
In addition, CBT has been shown to significantly reduce the recurrence of depression over the following 1-2 years (Gloaguen et al., 1997). In a six year study of patients suffering from recurrent depression, those who received CBT after initial pharmacotherapy exhibited a significantly lower relapse rate at a six year follow-up compared to those who did not receive CBT (Fava, Ruini, Rafanelli, Fionis, Conti, & Grandi, 2004).