Problem-solving therapy and supportive therapy in older adults with major depression and executive dysfunction: effect on disability

Abstract

Context: Older patients with depression and executive dysfunction represent a population with significant disability and a high likelihood of failing pharmacotherapy.

Objectives: To examine whether problem-solving therapy (PST) reduces disability more than does supportive therapy (ST) in older patients with depression and executive dysfunction and whether this effect is mediated by improvement in depressive symptoms.

Design: Randomized controlled trial.

Setting: Weill Cornell Medical College and University of California at San Francisco.

Participants: Adults (aged >59 years) with major depression and executive dysfunction recruited between December 2002 and November 2007 and followed up for 36 weeks. Intervention Twelve sessions of PST modified for older depressed adults with executive impairment or ST. Main Outcome Measure Disability as quantified using the 12-item World Health Organization Disability Assessment Schedule II.

Results: Of 653 individuals referred to this study, 221 met the inclusion criteria and were randomized to receive PST or ST. Both PST and ST led to comparable improvement in disability in the first 6 weeks of treatment, but a more prominent reduction was noted in PST participants at weeks 9 and 12. The difference between PST and ST was greater in patients with greater cognitive impairment and more previous episodes. Reduction in disability paralleled reduction in depressive symptoms. The therapeutic advantage of PST over ST in reducing depression was, in part, due to greater reduction in disability by PST. Although disability increased during the 24 weeks after the end of treatment, the advantage of PST over ST was retained.

Conclusions: These results suggest that PST is more effective than ST in reducing disability in older patients with major depression and executive dysfunction, and its benefits were retained after the end of treatment. The clinical value of this finding is that PST may be a treatment alternative in an older patient population likely to be resistant to pharmacotherapy.

Trial registration: clinicaltrials.gov Identifier: NCT00052091.

Figure 1. Flow of Subjects into the Treatment Trial

Figure 2. Disability (WHODAS) Scores Over 12 Weeks of Treatment with Problem Solving Therapy (PST) vs. Supportive Therapy (ST) in 221 Older Adults with Major Depression and Executive Dysfunction

The curves are based on the Least Squares Means of the Mixed Effects Model: Time + Treatment + Site + Time Square + Treatment × Time (Treatment × Time: t=0.31, df=1, 202, p=0.0128) with 1 Standard Error above and below the mean. PST: Problem Solving Therapy, ST: Supportive Therapy.

Figure 3. Moderators of Problem Solving Therapy Efficacy (vs. Supportive Therapy) on Disability in 221 Older Adults with Major Depression

Mini Mental State Exam (MMSE) scores at baseline (F=4.51, df=1, 200, p=0.035) and Number of Depressive Episodes (F=4.15, df=1, 153, p=0.043) moderate the effects of treatment on disability. MMSE low and MMSE high scores are 1 Standard Deviations below and above the mean, respectively (Mean=27.8; SD=1.71); Low Number of Depressive Episodes =1 and High Number of Depressive Episodes =4.

Figure 3. Moderators of Problem Solving Therapy Efficacy (vs. Supportive Therapy) on Disability in 221 Older Adults with Major Depression

Mini Mental State Exam (MMSE) scores at baseline (F=4.51, df=1, 200, p=0.035) and Number of Depressive Episodes (F=4.15, df=1, 153, p=0.043) moderate the effects of treatment on disability. MMSE low and MMSE high scores are 1 Standard Deviations below and above the mean, respectively (Mean=27.8; SD=1.71); Low Number of Depressive Episodes =1 and High Number of Depressive Episodes =4.

Figure 4. Course of Disability After Treatment Completion (12–36 Weeks) in 206 Older Adults with Major Depression and Executive Dysfunction

Curves are based on the Least Squares Means of the Mixed Effects Model: Time + Treatment + Site + Baseline WHODAS + Treatment × Time (Treatment × Time: t=0.31, df=1, 142, p=0.7574) with 1 Standard Error above and below the mean. PST: Problem Solving Therapy, ST: Supportive Therapy.