The primary aim of this study was to examine the effects of a home-based expressive writing intervention among MBC patients, with a secondary goal of investigating whether these effects varied as a function of perceived emotional support and time since metastatic diagnosis. Contrary to hypotheses, expressive writing did not produce reductions in psychological distress (i.e., general depressive symptoms and cancer-specific intrusive thoughts) or improvements in physical health (i.e., fewer sleep disturbances and somatic symptoms). This finding is inconsistent with previous trials conducted with early stage breast cancer patients (Stanton et al., 2002
) as well as newly diagnosed metastatic renal cell carcinoma patients (de Moor et al., 2002
). However, to our knowledge, this is the first randomized controlled trial to examine the effects of emotionally expressive writing among MBC patients, and several characteristics of the current sample are distinct from these previous samples. First, most women in our sample reported that they had taken action to process and express their cancer-related emotions before participating in our study. For example, three-quarters had attended a cancer support group (vs. less than half in Stanton et al., 2002
) and two-thirds had previously written in a journal about the cancer experience. Thus, the lack of main effects in the current study may because of the fact that most women had already engaged in significant emotional processing and expression about their cancer before randomization. Unfortunately, given the frequency of these experiences in our sample, the study was not powered to detect whether the intervention was efficacious among the 10 women who had not previously participated in a cancer support group or talked with a mental health professional about cancer. Our study also differed from previous studies in that the control group was also instructed to write about their cancer, which may have been a more stringent control condition than, for example, health behaviors (de Moor et al., 2002
Another notable characteristic is the medical heterogeneity of our sample. While previous studies recruited patients at a particular stage in the cancer trajectory, such as immediately following diagnosis and before beginning an experimental treatment regimen (de Moor et al., 2002
) or after completing adjuvant treatment (Stanton et al., 2002
), we observed significant variability in how long participants had been living with MBC. Indeed, we found that the effects of the intervention were moderated by time since metastatic diagnosis. Women who had been recently diagnosed appeared to benefit from the intervention with respect to somatic symptoms, whereas there was no effect on somatic symptoms for women that had been living with MBC for longer. However, women who had been living with the diagnosis for a longer time appeared to be adversely affected by the expressive writing intervention with respect to sleep, reporting more sleep disturbances at follow-up relative to the control group. Perhaps for women who have been living with a diagnosis of MBC for several years, asking them to revisit negative thoughts and emotions has detrimental effects on sleep. It is also possible that women who had been living with the diagnosis for a longer time were more likely to be facing mortality concerns than the more recently diagnosed and that writing about these existential concerns resulted in disrupted sleep. We will explore whether the content of participants’ essays differed by time since diagnosis in future analyses.
We also examined perceived emotional support as a moderator of intervention effects. This hypothesis was guided by social constraint theory, which suggests that the absence of social outlets for emotional expression and processing has a negative effect on adjustment to stressful situations. As hypothesized, women reporting low emotional support benefited from the opportunity to express and process cancer-related emotions, which was reflected in decreased intrusive thoughts at 3 months. These results are consistent with an earlier writing trial with cancer patients, and suggest that expressive writing may represent a useful intervention for individuals who lack opportunities for emotional expression in their social environments (Zakowski et al., 2004
Limitations of the current study warrant mention. First, the sample was predominantly White and well educated, and results may not generalize to individuals with less education, to ethnic minority groups, or to men. Second, physical health outcome measures relied on self-report. Although physical symptoms and sleep disturbances have been examined in previous expressive writing studies and are elevated in MBC patients (Koopman et al., 2002
), future research should examine biological markers that might be clinically relevant for MBC patients. Although the sample of 31 women per condition at follow-up is larger than as those in previous expressive writing trials reporting main effects (de Moor et al., 2002
; Stanton et al., 2002
), our study may have been underpowered to detect main effects, particularly for psychological outcomes, as well as moderated effects. Thus, replication of the current design in a larger sample will be another important goal for future research. Future research may also benefit from exploration of alternative writing topics, such as the perceived benefits of the cancer experience (Stanton et al., 2002
) or a noncancer related control topic.
Strengths of the study include the application of the expressive writing paradigm to a novel and understudied clinical population, the randomized controlled design, the inclusion of both psychological and physical health outcome variables, and the 3-month follow-up period. Although there was no main effect of expressive writing on health among the current MBC sample, analyses provide suggestive evidence that expressive writing may be beneficial for a subset of MBC patients and contraindicated for others. Emotionally expressive writing holds promise as a cost-effective, brief psychosocial intervention for women living with MBC who have been recently diagnosed or who report low levels of social support.