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Class 11 -12. Chapters 5 & Elkins (1989). Elkin et al: Purpose . Test feasibility of the collaborative clinical trial model Examine relative efficacy of CBT, IPT , and Medication for Depression. NIMH Treatment of Depression Collaborative Research Program. U. of Pittsburg

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Class 11 -12

Chapters 5 & Elkins (1989)


Elkin et al: Purpose

  • Test feasibility of the collaborative clinical trial model

  • Examine relative efficacy of CBT, IPT, and Medication for Depression


NIMH Treatment of Depression Collaborative Research Program

  • U. of Pittsburg

  • George Washington U.

  • U. of Oklahoma

  • 250 Patients: Major depressive disorder

  • 28 therapists: years experience 2 -27; 71% male

    • 10 psychologists

    • 18 psychiatrists


Experimental Between-Group Designs

  • Post-Test Only Control

  • Pre-Test -- Post-Test Control

  • Solomon Four Group (combination of 1 and 2 above)

  • Factorial Design

    • more than one independent variable; interactions treatment X therapist or patient characteristic

  • Dependent Sample Design (Matching)


Experimental Between-Group Designs

  • Post-Test Only Control

  • Pre-Test -- Post-Test Control

  • Solomon Four Group (combination of 1 and 2 above)

  • Factorial Design - Post Hoc

    • more than one independent variable; interactions

      • treatment X patient characteristic (depression level at intake)

  • Dependent Sample Design (Matching)


IVs: Experimental Groups:

Cognitive Behavioral Therapy

Interpersonal Therapy

16 individual sessions/ 50 min.

Medication+ Clinical Management*

Pill-Placebo+ Clinical Management*

1st session 55 min.; then 20 to 25 min.

* Minimal supportive therapy condition

6


Dependent Variables


Dependent Variables


Outcome Research Strategies

  • Primary Analyses

  • Secondary Analyses (Post-Hoc)


Outcome Research Strategies

  • Primary Analyses

    • Treatment package

    • Comparative

  • Secondary Analyses

    • Client Variation-moderation effect?


Outcome Research Strategies

  • Secondary Analyses

    • Client Variation-moderation effect

      depression level at intake as moderator of relation of treatment groups to outcome

      Were outcomes across treatment types different for patients with higher versus lower levels of depression at pre-test?


Control Groups

  • CBT

  • IPT

  • Medication+ Clinical Management*

  • Pill- Placebo+ Clinical Management*

    * Minimal supportive therapy condition


Treatments & Therapists


Ensure Valid Treatments

  • Specify the treatment(s)

  • Therapist training/monitoring

  • Fidelity Checks


Ensure Valid Treatments

  • Specify the treatment(s)

    • Manuals

  • Therapist training/monitoring

  • Fidelity Checks- therapy tapes

    • Collaborative Study Psychotherapy Rating Scale (CSPRS)

    • Treatments could be discriminated 95% of the time


Attrition (>15 sessions or 12 weeks)


Which group to use in outcome analysis??


Assessment Times

  • Pre treatment

  • Post Treatment

    • 4, 8, 12 weeks

    • Termination – 15 weeks

    • Follow up: 6, 12, 18 months


Analyses of Pre-test/Post-test (1)

  • Paired T-Test to examine differences between pre-test and post-test scores (p. 974)

  • How Many ??


Table 1 Completer Group: At least 12 sessions; n=155 (page 975)


Analyses of Pre-test/Post-test (1)

  • Paired T-Test to examine differences between pre-test and post-test scores (p. 974)

  • How Many ??

    4 Treatment groups X 4Outcome measures

    CBT HRSD

    IPT GAS

    IMI-CM BDI

    Pla-CM HSCL-90

    X 3 Samples – Completers; End Point 204; 239


Findings – T-Tests


Analyses of Post-test scores

  • Use pre-test as a covariate in analyses of co-variance to compare mean post-test scores across the 4 treatment groups

    • Calculate a residualized change scores – amount of variability in the post-test that is not associated with the pre-test score

  • Used a P<.10 in ANCOVAS and

    p = .10/.06 = .017 for pair-wise comparisons

    (p.974)


ANCOVAS: Post test scores

  • Statistically significant differences between groups in scales at post-test

    • Four 3 X 4 ANCOVAS: differences across treatments in Post-treatment scoresin: HRSD, GAS--- BDI, HSCL90

  • 3 (sites) X 4 (treatment groups)

  • Analyses reported only for treatment groups combining them across sites


Co-Variates

  • Pre-test scores

  • Marriage Status (1,2)

    • Why not MANCOVAS? P.973


Table 1 Completer Group: At least 12 sessions; n=155 (page 975) p<.10


Table 1 End Point 239 Group CBT IPT IMI-CM PLA-CM p<.10


Findings Pair-wise Comparisons


Measuring Change Elkin et al. 1989

  • Statistical significance

  • Clinical significance


Measuring Change Elkin et al. 1989

  • Statistical significance

    • Differences between groups in scales at post-test controlling for pre-test scores

  • Clinical significance

    • Percentage of participants that changed from dysfunctional to functional level (using cut-off scores)


Clinical Significance

  • Recovery Analysis

    • Proportion of patients who improved vs. not improved

  • Cut Off Scores

    • Not Depressed HRSD < 6 and BDI < 9

    • Depressed HRSD >6 or BDI > 9

  • Statistical Analyses

    • Chi square: Proportion of depressed and non-depressed patients across treatment groups at termination.


End Point 239 HRSD p = .04CBT IPTIMI-CMP-CM

  • Chi Square (Χ2) tests to what extent the proportion in each group is what may be expected by chance or if it is larger or smaller than expected…….

    • IPT = IMI-CM>Placebo-CM

    • CBT - % comparison was not sig. for any group


Secondary Analyses

  • To examine effect of pre-treatment severity (HRSD/GAS) on outcome by treatment group

    • DVs: Post-treatment scores

    • Severity Criteria

      • HRSD>20 44% of sample

      • GAS<50 41%

    • Covariate Marital Status


2X4 ANCOVA (severity x treatment) DVs- Post TestHRSD, GAS, BDI, HSCL-90

  • Main Effect for

  • Main Effect for

  • (Interaction term)***


2X4 ANCOVA (severity x treatment) DVs- Post TestHRSD, GAS, BDI, HSCL-90

  • Main Effect for Severity

    • More Severe Pre-Test HRSD>20; GAS<50

    • Less Severe Pre-Test

  • Main Effect for Treatment

    • CBT

    • IPT

    • IMI-CM

    • P-CM

  • Severity X Treatment(interaction term)*******


Interaction Effect HRSD Severity x TGDependent Variables: HRSD* GAS, BDI, HSCL-90 (p.976)


Interaction EffectGAS Severity x TG: Dependent Variables: HRSDGAS,BDI, HSCL-90


Treatment by Severity Interaction/end-point 204 sampleHigher score Negative OutcomeHigher Score Positive Outcome


Summary All Pairwise analyses following interaction effects p.976

  • Less severe groups: no differences across treatment groups

  • More severegroups

    • IPTmore effective than PLA-CM in 3 instances all in the HRSDmeasure in the END Point Sample 204 (3 out of 4 comparisons)

    • IMI-CM more effective thanPLA-CM across a number of measures (8 out 10 comparisons)


Figure 2Recovery Rates (%) endpoint /204 sample


Figure 2 Recovery Rates (%) endpoint /204 sample for severity groups (p.977)

  • Less severe subgroups: NS differences among treatments for all samples with HRSD or GAS.

  • More severe subgroups for HRSD and GAS:

    • Consistent findings across the three samples

    • IPT>PLA-CM 5/6 and IMI-CM>PLA-CM 6/6


Results: Summary 1/3

  • Paired T test showed stat. sig. differences (p<.001) in Pre- Post scores in all measures for all three groups of participants (even placebo pill/CM)

    • Intent-to treat

    • Completers Minimum

      • 3.5<Sessions

    • Completers of all or most sessions

      • At least 12<sessions > 15 (n=155)


Results: Summary 2/3

  • ANCOVAS showed

    • no stat sig differences in pre-test scores in any measure for any treatment group

    • Stat sig differences in post-test

      • BDI/HSCL90Completers

      • HSRD/GAS Total Group (239)


Results: Summary 3/3

  • Pairwise Follow-up ANCOVA

    • HSCL-90 IMI-CM> PLA-CM (Completer)

    • GAS -- IMI-CM>PLA-CM (Total 239 group)

    • HRSDIPT, IMI-CM>trend PLA-CM (Total 239)

  • Recovery Findings (Clinical Significance)

    • IPT, IMI-CM > PLA-CM ( End-Point 239)

    • 43% 42% 21% Post-test HRSD<6

      CBT = 36% NS


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