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Symptom courses during and after psychotherapy: models and simulations. Robert Per č evi ć June 2007. Treatment Courses. T he Random Walk Model. x t = ?. T he Random Walk Model. x t =x t-1. x. t. T he Random Walk Model. x t =x t-1 +c c<0. x. t. T he Random Walk Model.
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Symptom courses during and after psychotherapy: models and simulations Robert Perčević June 2007
The Random Walk Model xt= ?
The Random Walk Model xt=xt-1 x t
The Random Walk Model xt=xt-1+c c<0 x t
The Random Walk Model Random Variable xt=xt-1+c+ψc<0 V(ψ)>0, E(ψ)=0
The Random Walk Model with Measurement Error xt=xt-1+c+ψ+εt-εt-1c<0 V(ψ)>0, E(ψ)=0 V(ε)>0, E(ε)=0
Empirical Verification • Hypothesis: • (a) homogeneous and (b) independent change rates • Sample: • Specialized psychotherapeutic hospital • 1210 patients • Most common diagnosis: F32, F33, F60, F50 • Treatment between 2 and 77 days • Up to 9 assessments per patient • 4149 observations • Method: • HLM; (xi,t - xi,t-1) / Δt = (β1 + ai) + (β2 + bi)t + ε
Empirical Verification • Findings:
How to improve Outcomes? • Increase treatment length • Increase effectiveness • Match treatment and patient • Outcome monitoring • Identify non-reponders • Adapt treatment length to patients needs
How to improve Outcomes? • Increase treatment length • Increase effectiveness • Match treatment and patient • Outcome monitoring • Identify non-reponders • Adapt treatment length to patients needs
How to improve Outcomes? • Increase treatment length • Increase effectiveness • Match treatment and patient • Outcome monitoring • Identify non-reponders • Adapt treatment length to patients needs
How to improve Outcomes? • Increase treatment length • Increase effectiveness • Match treatment and patient • Outcome monitoring • Identify non-reponders • Adapt treatment length to patients needs
How to improve Outcomes? • Increase treatment length • Increase effectiveness • Match treatment and patient • Outcome monitoring • Identify non-reponders • Adapt treatment length to patients needs
Simulation: Treatment Length x(1…n,0)=initial_distress_distirbution FOR patient = 1 to n FOR time = 1… max_treatment_time x(patient,time)=x(patient,time-1)+c+randomvariable IF x(patient,time)<cutoff positive(time)=positive(time)+1 ENDIF ENDFOR ENDFOR PLOT(positive, 1… max_treatment_time)
Simulation: Treatment Length Dose-Effect / Cost-Effect / Cost-Benefit
Simulation: Treatment Length Dose-Effect / Cost-Effect / Cost-Benefit Efficiency: the relation between Effect and Effort
Stylized Facts r = -0.435
Model xt=xt-1+εt-εt-1 V(ε)>0, E(ε)=0
Model xt=xt-1+εt-εt-1 V(ε)>0, E(ε)=0
How to avoid Relapses? Low-intensity continuation of primary treatment