The current study provides partial support for our hypotheses and initial evidence that interactions among sets of psychosocial factors and changes in these factors over time in treatment may affect symptom reduction while treated with CIT. Specifically, results showed that, independent of ethnicity, education, final CIT dosage, and the direct effects of other psychosocial variables, increases in social support during the trial and exposure to both high social undermining and high social support at entry into treatment were associated with greater symptom improvement over the course of treatment with CIT. Results also showed that social undermining at treatment entry had a counterintuitive effect on symptom reduction among the Caucasians participants but not among the African-Americans. This finding is noteworthy given that there were no significant overall ethnic differences in treatment response regardless of whether response was measured as magnitude of pre-post change, remission rates, number of completers, number of visits made, final dose of medication or in side effect profiles (see Lesser et al., 2010
It is very interesting that the combination of high social undermining and high social support was the most conducive to symptom reduction and remission. One possibility is that those patients who evidenced the greatest improvement were those who experienced both greater criticism for their symptoms and functional limitations due to their depression along with strong support for seeking treatment. These experiences may have been conducive to behavioral activation, which is a common element of psychotherapeutic treatment for depression. It is also interesting that social support had little beneficial effect on those who had experienced low levels of social undermining, which supports the notion that social support serves best as a buffer between undesirable circumstances and psychological well-being. In contrast, increases in social support were directly associated with symptom reduction and remission, but decreases in social undermining had no effects on symptom improvement.
It is also important to note that contrary to expectation, burden of chronic stress had no effect on treatment outcome. This finding fits with theories of depression that underscore the strong role of interpersonal relationships in activating cognitive vulnerabilities to the onset and maintenance of major depression. It is also possible that chronic stressors may not have had a strong impact on depression during the trial due to participants’ adjustment to the presence of these ever-present stressors and these stressors not being salient on a daily basis throughout this short-term trial.
It is also interesting that, at low levels of social undermining, African-Americans fared better than Caucasians in terms of symptom reduction, but at high levels of social undermining, they were somewhat less able to achieve the same symptom reduction and the Caucasians fared better. In fact, Caucasians with high amounts of social undermining achieved greater symptom reduction than Caucasians with low amounts of social undermining. Was there some unmeasured characteristic of this sub-sample of participants that allowed them to thrive under conditions of social undermining and maybe use social undermining productively? Other empirical findings suggest that this may be a potential explanation. For example, Mazure and colleagues (2000)
found that stressful interpersonal events within the 6 months before the initiation of antidepressant treatment was related to better outcome after 6-weeks of treatment, particularly among individuals high on sociotrophy. Other possible explanations for this counter-intuitive finding were explored, but none were substantiated by the data. For example, the possibility that group differences in decreases in social undermining by the end of the trial (i.e., 2 months after baseline) could explain this finding was not substantiated because Caucasians and African-Americans did not differ on patterns of change in social undermining by the end of the trial. Additionally, although Caucasians with more baseline social undermining experienced significantly greater decrease in social undermining by the end of the trial than Caucasians with low baseline social undermining, they continued to experience relatively more social undermining at the end of the trial.
One possible explanation for our counterintuitive finding that we could not explore empirically is the possibility that the social undermining measure did not capture the most salient social undermining relationships in participants’ lives because the same four important people were rated for support and undermining. It is possible that others in participants’ lives engaged in much more undermining towards them and that participants did not happen to list these people as one of their four important people. Examples of potentially significant sources of undermining are supervisors and coworkers (e.g., Gant et al., 1993
), in-laws, friends or neighbors. Despite the fact that participants rated the same individuals on supportive behaviors and undermining behaviors, social support and social undermining variables were not correlated, i.e., r
= .05 at baseline and r
= .09 at Week 8. This lack of correlation indicates that, in our sample, support and undermining are different processes that occur contemporaneously within the same relationships. Similarly, Vinokur and colleagues have used confirmatory factor analyses to demonstrate that, although support and undermining are usually inversely correlated in their studies, they are not simply different manifestations of the same construct (e.g., Vinokur et al., 1996
; Vinokur & van Ryn, 1993
). Furthermore, most studies that examine support and undermining have participants rate the same individual on support and undermining. For example, much of the work in this area is on support and undermining from a spouse or significant other (e.g., Cranford, 2004
; Vinokur & van Ryn, 1993
; Vinokur & Vinokur-Kaplan, 1990
The findings from our study suggest that future clinical trials should give more attention to assessing and tracking changes in psychosocial factors. Our findings also demonstrate that, using standardized protocols and adequate individualized medical attention, individuals with different levels of chronic stress burdens can achieve equivalent levels of symptom reduction and remission. Findings from the current study also suggest that, for individuals experiencing high levels of social undermining upon initiating antidepressant treatment, social support interventions might be useful adjuncts. Additionally, particularly for African-Americans, engaging an individual’s close social network in the treatment process and problem solving may be especially helpful. Finally, the fact that social undermining influenced whether participants completed the trial supports the notion that psychosocial factors are likely to affect treatment compliance and treatment response to pharmacotherapy.
Several limitations should be noted in interpreting these findings. First, due to the relatively modest sample size and consequent power limitations, null findings in this paper should be interpreted with caution. Second, it is also important not to assume that these findings will generalize to other treatment samples because the medications were provided free of charge to study participants. Outside of a clinical trial, financially disadvantaged patients are likely to experience poorer treatment response due to the inability to consistently access and pay for medications.
Third, because the focus of this trial was the examination of ethnic differences in treatment response rather than the efficacy of CIT, which has already been well documented, the study did not include a placebo-control group. Therefore, the effects of CIT, psychosocial variables, and unexamined variables cannot be easily disentangled. Along these lines, in the case of the association between social support change and symptom change and remission, causality cannot be determined. In other words, it may be possible that those who were experiencing more symptom improvement in the first several weeks of the trial (i.e., less depressed than at baseline) were better able to enlist social support by the end of the trial or were able to perceive the social support they were already receiving at baseline more positively due to less entrapment in a negative cognitive style at that point. Finally, the current study only examined participants during their first 8 weeks of exposure to CIT. Future studies should include a longer follow-up period to test for the long-term effects of psychosocial variables on the maintenance of symptom improvements, as well as whether ethnic differences become more or less apparent after a longer follow-up period. Future treatment outcome studies should also test for the association between change in chronic stress burden over the course of treatment and improvement over time.
More studies are needed to replicate the current findings and directly explore explanations for these results. Future studies conducted by this research group will explore the associations of other psychosocial variables, such as childhood adversity, spirituality, and religiosity, as well as biological variables (i.e., differences between the groups in the distribution of gene polymorphisms in the promoter region of the serotonin transporter and CYP2C19 genes), with symptom reduction in this trial. One promising suggestion of this study is that, although psychosocial variables may make some difference in the amount of symptom improvement and likelihood of remission, more participants responded to antidepressant treatment despite adverse psychosocial circumstances than did not respond.