The Effects of CBT (Cognitive Behavioral Therapy)

Study Objective

This study aimed to compare the effects of self-help psychotherapy books based on cognitive behavioral therapy theories (CT, CBT (Cognitive Behavioral Therapy), ACT, and schema therapy) on depressive symptoms with those of a placebo psychology book and a control group that received no book recommendation. The study aimed to compare the effects of ‘Fark Et, Düşün, Hisset, Yaşa’, ‘Hayatı Yeniden Keşfedin’, ‘İyi Hissetmek’, and ‘Mutluluk Tuzağı’ on depressive symptoms in patients with depression and anxiety disorders with those of 'İnsan Olmak', selected as a placebo book because it contains no cognitive behavioral therapy interventions, and a treatment-as-usual group that received no book recommendation. Our randomized controlled study examined patients who were recommended the experimental self-help books, those who received no book recommendation, and those who were recommended the placebo book.

Study Methods

Volunteer patients diagnosed with depression or an anxiety disorder, with at least a primary school education, who attended the Psychiatry Outpatient Clinic at Marmara University Pendik Training and Research Hospital between July 2019 and February 2020 were enrolled. The SCID-I was administered to all patients who agreed to participate, and book recommendations were randomly assigned to patients in the depression and anxiety disorder groups. All patients, whether or not they received a book recommendation, continued their routine outpatient treatment. The GAS, WHOQOL, DASS-21, BAI, and BDI scales were used in the study. One-month assessments were completed for 63 of the 110 participants. Recruitment of new patients could not continue because of the coronavirus pandemic. A mixed-design ANOVA was performed to examine the interaction between books and time. A second ANOVA was performed, excluding the treatment-as-usual group, to compare the experimental books with the placebo book. Approval for the study was obtained from the Marmara University Ethics Committee under approval number 09.2019.693.

Study Findings

The mixed-design ANOVA showed a statistically significant difference between books in the reduction in Beck Depression Inventory (BDI) scores (F(5,57)=2.621, p=0.033, ηp2=0.187). Although post-hoc analyses did not indicate a statistically significant difference between books over time, the planned contrast analysis showed that, when the books were considered collectively, the reduction in depression scores differed significantly from the reduction observed with treatment as usual (t(57)=2.525, p=0.014). When the analysis was repeated after excluding the treatment-as-usual group, similar results were found in comparison with the placebo book group (t(48)=2.501, p=0.016). However, no statistically significant differences were found (F3,40 = 0.227, p = 0.887, ηp2 = 0.017).

Study Conclusion

In patients diagnosed with depression and anxiety disorders, self-help books on acceptance and commitment therapy, cognitive therapy, cognitive behavioral therapy, and schema therapy, developed within the theoretical framework of CBT (Cognitive Behavioral Therapy), are significantly more effective in reducing depression scores than the placebo book and treatment as usual. Further research is needed to observe the long-term effects of these books.