Cognitive and Psychodynamic Mechanisms of Change in Treated and Untreated Depression

Background and Purpose: Depression is important to social work due to the high prevalence of depression, and the reciprocal relationship between poverty and depression. Cognitive-behavioral therapy (CBT) and psychodynamic therapy (PT) are two of the most widely-used therapeutic approaches in the individual treatment of depression. Manualized versions of CBT have well-replicated efficacy studies, while PT has shown good results in a number of studies, but with less rigorous replication due to use of different manuals. One of the next challenges to psychotherapy research is identifying the mechanisms of change, or active ingredients, of effective treatments. A number of studies have shown that changes in cognition predict reduced depression, and several studies showed changes in defenses were associated with reduced depression. This study is only the second to include both CBT and PT measures, and this sample of lower SES participants with recurrent depression differs from the higher SES, single episode depression participants found in the majority of the existing research.

Methods: Sixty-five participants were diagnosed with depression via structured clinical interview and subsequently completed questionnaires at three time points, including measures of cognition, defenses, and mental health symptoms. Reliabilities of all measures were good to excellent. Participants were recruited from the community, and 46% were receiving treatment for depression (medication, psychotherapy, or both). Of the 65 participants, 71% were women (n=46), 77% were white (n=50), the average age was 41.7 years (SD=14.4), and half of the participants (52.3%) were from a lower income socioeconomic status (n=34), The mean level of psychiatric symptoms exceeded published outpatient norms, and 66% had recurrent major depression.

Results: There were small statistically significant decreases across all time points in mean levels of depression, general psychiatric symptoms, automatic thoughts, and immature defenses, and increases in mature defenses. Early changes in automatic thoughts and immature defenses were associated with symptom change from time-one to time-three. The directionality of early automatic thought change predicting symptom change was partially supported, but immature defense change occurs simultaneously with, or after, symptom change. Changes in automatic thoughts were significantly correlated with changes in immature defenses.There were no differences between those receiving treatment and those not receiving treatment in any of these relationships.

Conclusions and Implications: Given the convergent evidence of cognitive change as a mediator of depression reduction, all depression therapies should consider how they address depressive cognition. To build a more complete understanding of how to ameliorate depression, future studies should continue to include constructs from multiple theories. Multitheoretical research may lead to the development of new, more effective treatments. This is the first study that tested CBT and PT mechanisms in untreated depression, suggesting change in cognition and defenses are generic processes not limited to theory-specific therapies. Limitations of the study include primary self-report measures, and partially cross-sectional analysis. Parallel dynamics were observed with this low SES sample, as previous studies with middle-class samples, suggesting similar dynamics of depression across these socioeconomic differences. Further research is needed on the application of evidence-based treatments across sociocultural differences.