单选题 Mounting evidence shows that behavioral-activation ( BA) therapy is just as effective as cognitive-behavioral therapy ( CBT) in treating depression.Unlike CBT，BA is an outside-in 26_____ in which therapists focus on modifying actions rather than thoughts."

The idea is that what you do and how you feel are 27_____ ,"says David Richards，a health services researcher at the University of Exeter.If a patient values nature and family，for example，a therapist might encourage him to 28_____ a daily walk in the park with his grandchildren，which could create a(n) 29_____ to more negative pastimes such as pondering on loss. BA has existed for decades，and some of its elements are used in CBT，yet more 30_____ scientific evidence is needed to assess its relative strength as a stand-alone approach.In a recent study，a 31_____ of 18 researchers led by Richards put BA and CBT head-to-head.

They 32_____ 440 people with depression to about 16 weeks of one of the two approaches，then followed the patients' progress at 6，12 and 18 months after treatment began.As 33_____ in a paper published in the Lancet，the team found the treatments to be equally effective. 

 In addition，Richards and his colleagues found that 34_____ health workers could provide BA after a brief training period—making it 35_____ cheaper to implement than CBT，which requires highly specialized therapists.That distinction could make the former a boon to developing countries，where resources for mental health are especially scarce.

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