Final answer:
Beck's cognitive therapy has primarily been applied to the treatment of depression, with extensive research and publications supporting its effectiveness in this area.
Step-by-step explanation:
Beck's cognitive therapy has been most widely applied to the treatment of depression. Developed by Aaron T. Beck, cognitive therapy is based on the cognitive model which suggests that thoughts, feelings, and behaviors are interconnected, and that individuals can move toward recovery by changing dysfunctional thoughts and beliefs. This approach has been refined over years through various publications and research, including Beck's own work from 1976 and 2008 outlining the application of cognitive therapy to emotional disorders, particularly depression, and its evolution and neurobiological correlates.
In various studies and meta-analyses, such as the one conducted by Butlera et al. in 2006, cognitive-behavioral therapy (CBT), which includes Beck's cognitive therapy, has been shown to be effective in treating depression. The Guilford Press published comprehensive guides on cognitive therapy of depression, further supporting its primary application in this area.