Figure A1: Simplified Markov Model Schematic: Guided iCBT with a Stepped-Care Approach.

Abbreviation: MDE, major depressive episode.

Note: Figure A1 depicts an individual-level (microsimulation) model that includes 11 Markov health states, each represented by an oval, reflecting the course of major depression. The simulation starts with a hypothetical person aged between 18 and 75 years with a mild or moderate major depressive episode. Each week cycle, the person has a chance to move among health states. Death is an absorbing Markov health state. In the acute initial phase lasting 12 weeks, a course of iCBT is applied. In two recurrent states, in-person CBT is the therapy of choice. People are allowed to drop out. The model accounts for the age at onset of major depression, counts the number of recurrent events, and modifies the risk of future major depressive episodes and changes in treatment accordingly. The model also takes into account the probability of death as a result of suicide according to the severity of disease and the probability of hospitalization in the complex depression health state. Transfer to the complex depression health state depends on the number of prior major depressive episodes-.