3.1 Baseline Comparisons of Randomized Groups
presents the demographic data for each experimental condition within each sample. To determine the success of randomization, we compared disclosure and control groups on demographics (age, sex, ethnicity [European American vs. minority—African American and Hispanic combined], duration of RA, and education) and baseline levels of the health status measures. Among the 88 patients in the writing sample, the 43 disclosure patients did not differ from the 45 combined controls (all p > .28) on demographics and all but one of the baseline health measures; disclosure writers had higher baseline ESR (M = 48.86, SD = 22.10) than combined controls (M = 34.37, SD = 22.79), (p = .007), and the neutral controls in particular (M = 30.44, SD = 21.04), p = .005. Otherwise, disclosure writers did not differ from either positive or neutral controls.
Among the 93 patients in the speaking sample, the 48 disclosure patients did not differ from the 45 combined controls on any demographic or baseline health variable (all p > .12). Similarly, the disclosure speakers did not differ from the positive control speakers on any health variable, although disclosure speakers were slightly less educated (M = 13.14 years, SD = 2.40) than positive controls (M = 14.50, SD = 3.14), p = .04. Disclosure speakers were not different from neutral control speaker on any baseline measure, except disclosure speakers had lower physician's global rating of disease activity (M = 27.61, SD = 17.16) than neutral controls (M = 38.56, SD = 19.85), p = .02.
3.2 Patient Flow, Attrition, and Adherence
As shown in , drop-outs occurred almost exclusively immediately after the randomization. Because patients learned fully about the study, consented, did the baseline assessment, and were randomized during one session, some patients simply waited until they got home before informing us that they did not want to participate. In the writing sample, 14 of the 88 patients (15.9%) dropped from the study, and drop-out did not differ between disclosure (14%) and combined controls (17.8%), positive controls (25%), or neutral controls (9.5%). However, dropping from the writing sample was associated with being male, χ2 = 4.88, p = .03 (35.7% of men vs. 12.2% of women dropped) or ethnic minority, χ2 = 6.35, p = .01 (26.2% of minorities vs. 6.5% of European Americans dropped), and marginally associated with having RA for fewer years (7.9 vs. 14.3 years), t(85) = 1.96, p = .054. Other demographics (age, education) and most health status measures were unrelated to attrition (all p > .18); however, those who dropped had higher affective pain at baseline (M = 1.0, SD = 1.06) than those who remained in the study (M = 0.40, SD = 0.57), t(84) = 2.92, p = .004.
In the speaking sample, 16 of the 93 patients (17.2%) dropped, and drop-out did not differ significantly between disclosure (22.9%) and combined control groups (11.1%,), positive controls (16.9%), or neutral controls (4.8%). Drop-out from the speaking sample was marginally related to being male, χ2 = 3.23, p = .07 (33.3% of men vs. 14.1% of women), but was unrelated to all other demographic and baseline measures, including ethnicity (17.9% of minorities, and 16.7% of European Americans).
Patients who remained in the study returned their writings or audiotapes, which were reviewed for adherence and content. Of the 74 patients retained in the writing sample, all but two completed all four days of writing; one of the 37 disclosure writers completed two days, and one of the 37 control writers (a neutral control patient) completed three days. Of the 77 patients retained in the speaking sample, 37 had been assigned to disclosure, and of them, 32 did all four days, two patients did three days, and one patient each completed two, one, and zero days. Of the 40 control speakers, 38 did all four days, one (a positive control) did three days, and one (a positive control) did two days. Thus, adherence to the intervention sessions was quite high among both writing groups and the speaking groups.
For the writing sample, disclosure (M = 3.64, SD = 1.49) did not differ in credibility from combined controls (M = 3.59, SD = 1.87, p = .89), positive control (M = 3.99, SD = 1.53, p = .43), or neutral control (M = 3.21, SD = 2.12, p = .39). Similarly, for the speaking sample, disclosure (M = 3.32, SD = 1.52) did not differ in credibility from the combined controls (M = 3.83, SD = 1.56, p = .22); however, the spoken disclosure condition was viewed as less credible than the positive control (M = 4.30, SD = 1.46, p = .02), and very similar to the neutral control (M = 3.33, SD = 1.55, p = .98). Thus, for both samples, the control condition(s) were viewed at least as, if not more credible than, the disclosure condition as a stress management technique. It is notable, however, that all conditions received only moderate credibility ratings (i.e., the mid-point of the 1 to 7 scale).
3.4 Mood and Post-Session Ratings
presents the mean change in each of the four moods (post-session minus pre-session) as well as the post-session ratings, averaged across all days for each patient, for both the writing sample (top half of the table) and speaking sample (bottom half). In the writing sample, compared to combined controls, disclosure led to significantly larger increases in anger, sadness, and guilt, but not fear, during the sessions. These effects were due largely to differences between the disclosure and positive control groups, but not the neutral control group. Post-session ratings showed that disclosure patients rated their writing as significantly more personal, revealing, and meaningful, than did the combined controls, but all of these differences were due solely to comparisons between disclosure and the neutral controls; as intended, positive controls were similar to the disclosure condition on these measures. Also, disclosure writers reported higher levels of inhibition than both positive and neutral controls, supporting the expectation that disclosure dealt with relatively inhibited topics.
Mood Change and Post-session Ratings for the Disclosure and Control Groups (Combined, Positive, and Neutral) for the Writing Sample (Top) and Speaking Sample (Bottom)
In the speaking sample, disclosure led to more sadness than the combined controls (and the neutral control), but disclosure did not differ from the combined controls (or positive or neutral controls) on the other three moods. Disclosure led to significantly higher ratings of revealing and previous inhibition than combined controls, to greater inhibition than positive controls, and to greater personal nature, revealing, and meaningfulness than neutral controls.
3.5 Content Analyses
presents the various linguistic indices provided by LIWC for each condition. For the writing sample, compared with the combined controls, the disclosure group generated a significantly greater proportion of words that were categorized as first person, negative emotion, cognitive mechanism (including insight and causal thinking), and health-related; and these differences were found in comparison to both positive and neutral control conditions. As expected, disclosure writing led to less positive emotion word use than the positive control group. Disclosure did not differ from the positive control in the total number of words written, but the disclosure group wrote marginally more words than the neutral control group. For the speaking sample, the findings were generally similar to the writing sample, although first person words did not differ between disclosure and control conditions.
Linguistic Content for the Disclosure and Control Groups (Combined, Positive, and Neutral) for the Writing Sample (Top) and Speaking Sample (Bottom)
A doctoral student read all of the stress disclosure transcripts (both writing and speaking) and categorized the stressful topic(s) disclosed for each day. For both samples, a substantial portion of the daily transcripts focused on the patient's own health problems, typically RA (writing: 34%, speaking: 41%), followed by relationship conflicts, such as marital difficulties, divorce, or conflicts with friends (writing: 29%, speaking: 23%), and the death or illness of loved ones (writing: 24%, speaking: 20.5%). Other disclosed topics were much less common: experiences often linked with shame, such as having an affair, having an abortion, being arrested or jailed, bankruptcy, personal drug or alcohol problems (writing: 6%, speaking: 7%); childhood physical or sexual abuse (writing: 3%, speaking: 0%), family of origin problems such as parental divorce or drug use (writing: 1%, speaking: 0%), adult sexual or physical victimization (writing: 1%, speaking: 0%), and random stressors such as natural disasters, fires, accidents, being robbed, or witnessing violence (writing: 1%, speaking: 3%).
3.6 Primary Outcome Analyses for the Writing Sample: ANCOVAs
presents the primary outcome data for the writing sample, comparing the disclosure to both the combined controls as well as the positive and neutral controls, on all outcome measures at all four time-points (baseline and three follow-up points). The p-values for each follow-up time point are from ANCOVAs, comparing the disclosure group with each control group individually, covarying the baseline. (Note that baseline values in and are from only those participants who were retained in the study; that is, who provided any follow-up data.)
Writing Sample: Baseline and Follow-up Values of Outcome Measures for the Disclosure and Control Groups (Combined, Positive, Neutral), and Results of Analysis of Covariance at Each Follow-up Point
In the writing sample, disclosure led to significantly lower sensory pain at 1-month follow-up (pη2 = .06), and less affective pain at 6-month follow-up (pη2 = .08), than did the combined controls. For both variables, the disclosure group showed reductions in pain, in comparison to no change or slight increases in the combined controls. There were no significant effects of disclosure vs. combined control writing on any of the other health outcomes at any follow-up point.
Compared to the positive controls, there were two significant effects, both favoring disclosure. Disclosure writing led to less affective pain at 6-month follow-up (pη2 = .11), and greater grip strength at 3-month follow-up (pη2 = .11). Compared to the neutral control condition, there were three significant effects. Disclosure writing led to less sensory pain at 1-month follow-up (pη2 = .08) and faster walking speed at 6-month follow-up (pη2 = .09). There was one unexpected finding, however; the neutral control group had better erythrocyte sedimentation rate than the disclosure group at 6-month follow-up only (pη2 = .18).
3.7 Primary Outcome Analyses for the Speaking Sample: ANCOVAs
presents the primary outcome data for the speaking sample. Compared to the combined controls, disclosure speaking led to significantly less sensory pain (pη2 = .07) at 6-month follow-up, which was due to both improvement in the disclosure group and worsening in combined controls. Disclosure also led to significantly less affective pain (pη2 = .06) at 6-month follow-up than combined control, which was due solely to worsening in the control condition. In addition to these effects on pain, disclosure speaking led to a faster walking time (pη2 = .06) at 3-month follow-up, due to improvement in the disclosure group; fewer swollen joints (pη2 = .05) and an improved physician's global rating (pη2 = .09) at 6-month follow-up, due in both cases to much greater improvement in the disclosure than the combined control group.
Speaking Sample: Baseline and Follow-up Values of Outcome Measures for the Disclosure and Control Groups (Combined, Positive, Neutral), and Results of Analysis of Covariance at Each Follow-up Point
Compared to the positive controls, there were several significant effects, all favoring disclosure. Disclosure speaking led to less sensory pain at 3-month (pη2 = .08) and 6-month (pη2 = .11) follow-ups, and to fewer swollen joints (pη2 = .13) and improved physician's global rating (pη2 = .10) at the 6-month follow-up. Compared to the neutral control condition, there was only one effect: disclosure speaking led to improved physician's global rating at 6 months (pη2 = .10).
3.8 Primary Outcome Analyses: Latent Growth Curve Modeling
Latent growth curve analyses were then conducted for all outcome measures in order to obtain a more robust estimate of the influences of the experimental condition over time. Preliminary unconditional linear growth models were specified prior to testing the effects of disclosure versus control to confirm that a linear trajectory provided an optimal fit to the data and that there was significant variance in the slope term to warrant further conditional models. These preliminary analyses yielded adequately fitting models using the standard criteria of a non-significant model χ2, CFI > .9 and an RMSEA <.06 across all outcome variables (except for swollen joint count for comparisons with positive and neutral controls). We then estimated conditional growth models by regressing the experimental condition (disclosure vs. control) on each outcome variable. The path coefficients associated with these predictor variables assess the relationship of experimental condition with variability in the degree of change in the outcome over time.
The results are presented in , and the slope estimate and its p-value are the key indices. For the writing sample, disclosure led to significant improvements in affective pain and walking speed over time compared to combined controls. These effects stemmed from a marginally significant improvement in affective pain compared to the positive controls, and a significant improvement in walking time compared to the neutral controls, which were the only effects of disclosure when compared to the two specific control groups.
Results of Latent Growth Curve Modeling of Disclosure vs. Combined Control Groups, Positive Control, and Neutral Control for Patients in the Writing Sample (Top) and Speaking Sample (Bottom)
For the speaking sample, disclosure led only to marginal improvements in sensory pain when compared to the combined controls. However, disclosure led to significantly improved sensory pain, affective pain, and walking time when compared with the positive controls. There were no differences between disclosure and the neutral controls.