In the 1960s, Dr. Aaron T. Beck outlined a groundbreaking cognitive theory on the etiology of mental illness and a corresponding treatment, Cognitive Behavioral Therapy (CBT). One component of his cognitive theory is the cognitive specificity hypothesis, which posits that different mood and anxiety disorders are associated with a unique set of cognitive risk factors. There seems to be reasonable evidence to support this idea. For example, dysfunctional beliefs including self-criticism about one’s performance have been found to predict depression, whereas anxiety sensitivity, defined as fear of anxiety symptoms and their consequences, predicts panic disorder and beliefs about the need to control thoughts and prevent harm predict obsessive-compulsive disorder (OCD) This led to the establishment of specialized CBT treatments wherein each treatment is specifically tailored to address the unique vulnerabilities of the disorder.
On the other hand, recent research has also found evidence to suggest that these cognitive vulnerabilities are not disorder-specific and are actually linked to numerous disorders (i.e., are transdiagnostic risk factors), leading psychologists to question the benefits of specialized treatments. In addition to establishing cognitive vulnerabilities as predictors of the onset and maintenance of mood and anxiety disorders, research has found that a patient’s level of cognitive vulnerability at the beginning of treatment predicts how well they respond to CBT. In their study, ‘Cognitive Moderation of CBT: Disorder-Specific or Transdiagnostic Predictors of Treatment Response’ published in the journal Cognitive Therapy and Research, Katz et al. (2019) extended this line of research by testing whether the cognitive risk factors predict response to CBT in a disorder-specific or transdiagnostic manner. The study tested two competing hypotheses: 1) dysfunctional beliefs would specifically predict treatment response for depression, anxiety sensitivity would specifically predict treatment response for panic disorder, and obsessive beliefs would specifically predict treatment response for OCD (content specificity hypothesis); or 2) dysfunctional beliefs, anxiety sensitivity, and obsessive beliefs would each predict treatment response across all three disorders (transdiagnostic hypothesis).
The researchers recruited 373 adult patients between the ages of 18 and 65 from an outpatient clinic to participate in this study. There were 187 participants diagnosed with major depressive disorder, 85 participants diagnosed with panic disorder and 101 participants diagnosed with OCD. The participants were enrolled in either 12 (for panic disorder and OCD) or 14 weeks (for depression) of weekly group-based CBT that targeted their primary diagnosis. Participants completed questionnaires before and after treatment that assessed dysfunctional beliefs, obsessive beliefs, and anxiety sensitivity. Participants also completed questionnaires on the severity of the symptoms of their disorder.
Overall, the data supported the cognitive specificity hypothesis, such that patient response to treatment was predicted by unique cognitive risk factor for each disorder. In the major depressive disorder treatment group, patients’ dysfunctional beliefs about their performance predicted the amount of change in their symptoms of depression, such that patients with higher initial levels of dysfunctional beliefs had a poorer outcome. In contrast, anxiety sensitivity and obsessive beliefs were not significant predictors of change in depressive symptoms. Further, initial depressive symptoms also predicted change in dysfunctional beliefs. This may suggest a feedback loop in which this cognitive vulnerability maintains depressive symptoms and vice versa. In the OCD treatment group, obsessive beliefs predicted change in obsessive-compulsive symptoms, such that patients with higher initial levels of obsessive beliefs had a poorer outcome. Dysfunctional beliefs and anxiety sensitivity were not significant predictors of change in OCD symptoms. Finally, in the panic disorder treatment group, anxiety sensitivity predicted change in anxiety symptoms such that patients with higher initial levels of anxiety sensitivity had poorer outcome.
This data has important implications for clinical practice. Beck’s theory of cognitive specificity and the use of CBT treatment targeting underlying cognitive vulnerabilities related to specific disorders are supported by this study. Future studies should examine more closely those with high symptom severity and how to better address their needs, because this population benefited less from the CBT treatment.