Interventions that relieve both depression and pain best improve daily functioning and quality of life among patients with major depressive disorder, Taiwanese researchers have found.
Dr. Ching-Hua Lin and colleagues enrolled 131 new inpatients with major depressive disorder from Kai-Syuan Psychiatric Hospital in Kaohsiung, Taiwan, in their study. The patients ranged in age from 18 to 70 years, were physically healthy, and had received a major depressive disorder diagnosis using the Structured Clinical Interview for DSM-IV. After a washout period of 72 hours, the patients were given 20 mg/day of fluoxetine for 6 weeks, reported Dr. Lin of the hospital (Prog. Neuropsychopharmacol. Biol. Psychiatry 2013;47:93-8)
Researchers assessed depression severity, pain severity, daily functioning and quality of life (QOL) at baseline and at week 6 using the Hamilton Depression Rating Scale (HAMD-17), the Short Form 36 Body Pain Index (BPI), and the Work and Social Adjustment Scale (WSAS). They assessed health-related quality of life using three areas of the SF-36, including social functioning, vitality and general health perceptions.
They also proposed five models to explain the relationships among depression relief, pain relief, daily functioning improvement, and QOL improvement of depressed patients after treatment. In model 1, depression relief alone improved daily functioning and QOL; in 2, pain relief alone improved daily functioning and QOL; in 3, depression relief, mediated by pain relief, improved daily functioning and QOL; in 4, pain relief, mediated by depression relief, improved daily functioning and QOL; and in 5, both depression relief and pain relief improved daily functioning and QOL. The investigators used structural equation modeling to validate the models.
A total of 112 patients (85.5%) completed the fluoxetine trial, of whom 106 completed all assessments. Most of the patients (78%) were female; the mean age was 46 years. All assessments and measures changed significantly after the 6-week treatment. HAMD-17 scores improved from a mean 31.4 at baseline to a mean 13.7 (P less than .001) after fluoxetine treatment; BPI scores improved from a mean 45.3 to a mean 50.9 (P = .018); and WSAS scores improved from a mean 30.4 to a mean 22 (P less than 0.001). In health-related QOL measures, social function scores improved from a mean 34.1 to a mean 43.1 (P = .001); vitality improved from a mean 24.6 to a mean 33.7 (P less than .001) and general health perceptions improved from a mean 28 to a mean 35.9 (P = .001).
The researchers’ fifth hypothetical model, where both depression relief and pain relief that were interrelated affected improvement in daily functioning and QOL, was found to be the most accurate, explaining 57% of improvement variance. "The greater the depression symptoms and pain relief, the greater the improvement in daily functioning and QOL," the authors said. The investigators cited several limitations. For example, the sample size was relatively small, which made it possible to examine only limited variables. Also, they acknowledged that using different scales to measure depression, pain, daily functioning, and QOL might have yielded different results. They also pointed out that it is difficult to know whether the findings are generalizable, because the study focused in patients who were hospitalized because of severe depression.
Still, they said the study advanced the importance of understanding the relationship between depression and pain relief, and "their synergistic impact on daily functioning and QOL." "This study reinforced the need to effectively treat both depression and pain to achieve optimal outcomes," the authors wrote.
The study was funded by the hospital and the National Science Council of Taiwan. The authors reported no conflicts of interest.