Treatment of Dysthymia and Minor Depression in Primary Care A Randomized Trial in Patients Aged 18 to 59 Years

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Original Research

Treatment of Dysthymia and Minor Depression in Primary Care A Randomized Trial in Patients Aged 18 to 59 Years

J Fam Pract. 2001 May;50(5):405-412

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SF-36 Mental Health Component and Physical Health Component Scales

For the SF-36 MHC, on the intention-to-treat sample there was a significant baseline level by treatment group by time interaction (P=.006). Baseline MHC was then used as a covariate by dividing patient groups into tertiles on the basis of the baseline scores Table 3. Change from week 6 to week 11 was examined after controlling for baseline MHC within each group. With paroxetine there was significant improvement for the more impaired MHC group, +7.4 (SE=1.5), P <.001; and for the intermediate group, +4.3 (1.1), P <.003. For PST-PC, the absolute change for each MHC group was essentially similar: +3.1 (1.6) for the low group, +3.2 (1.3) for the intermediate group, and +3.2 (1.5) for the high group. These changes were not significant at the .05 level. For placebo, the amount of change was lower than that for the 2 active interventions; none of those changes approached statistical significance.

Results using the adequate exposure sample for the SF-36 MHC were similar overall to those obtained on the intention-to-treat analysis.

For the SF-36 PHC analyses there were no significant differences between any of the treatment groups.

Discussion

The findings from this study provide information about treatment response for these 2 diagnostic conditions, dysthymia and minor depression, in primary care patients. There are few data from other studies with which to compare these results; most treatment outcome results for these disorders come from patients treated in psychiatric settings. One study that does provide such data used a similar design and methodology on older patients (60 years and older) and was done in parallel with this study.²⁰ In that study, the patients showed improvement on all the interventions for the measures examined. However, whether outcome with the active treatments showed a significant difference over placebo plus nonspecific clinical management is clearly of interest. For this question, the results are more complex, with variations in outcome by site, diagnosis, and treatment for both age groups, depending on the measure used. The most easily interpreted results are the remission results obtained using the HDRS. These are also the reported results when all individuals received an adequate exposure to the treatment (4 or more visits). For dysthymia in the patients aged 18 to 59, there was an overall gradient with the highest recovery rate obtained for paroxetine, the next highest for PST-PC, and the lowest for placebo. The same pattern was evident for dysthymia in the patients aged 60 years and older; higher remission rates were obtained for both paroxetine and PST-PC than placebo.

When change was measured by decline over the 11-week trial on the HSCL-D-20 as the outcome variable, in the patients 60 years or older, those taking paroxetine had a significantly greater decline compared with those taking placebo at 11 weeks and a greater rate of decline from week 2 to 11. Patients receiving PST-PC did not show a significantly greater symptom reduction than those on placebo at 11 weeks, but they did show a significantly more rapid symptom reduction in weeks 2 to 11. For patients aged 18 to 59 years, there were no significant differences between the active treatments and placebo on this measure.

Results obtained using the SF-36 MHC are difficult to compare between the age groups because diagnosis showed a significant improvement in the patients 60 years and older but not in the patients aged 18 to 59 years. Dysthymic patients taking paroxetine who were 60 years and older with higher baseline MHC (less impaired) did significantly better at 11 weeks compared with those taking placebo; those receiving PST-PC did better but not significantly so. Patients with minor depression and low baseline MHC (more impaired) improved significantly more on both paroxetine and PST-PC compared with placebo. The patients aged 18 to 59 years showed a different pattern with diagnosis not relating to outcome, but all patients with low or intermediate baseline MHC improved significantly on paroxetine. Improvement amount on PST-PC fell between paroxetine and placebo, but was not significant. These results are difficult to interpret except to note that paroxetine did have a beneficial but modest effect in both age groups for some patients.

Taking an overview of the findings from both studies, it is worth noting that there are some consistent patterns of outcome related to treatment across the 2 age groups. In general, those patients taking paroxetine showed a greater improvement compared with placebo on one or more of the measures used. Similarly for PST-PC, on some measures there was a significant difference compared with placebo, although these results were more variable than those obtained with paroxetine. The greatest PST-PC versus placebo differences were present on the remission analyses; for both age groups, diagnosis was an important predictor with the best remission results obtained for patients with dysthymia. In both age groups, for those with minor depression there was a higher placebo response and almost no significant differences between either active treatment and placebo.