Major depressive disorder(MDD) is a disabling condition that adversely affects a person general health, work or school life, sleeping and eating habits, and person's family. MDD can strike anyone regardless of age, ethnic background, socioeconomic status or gender. Nearly 1 in 5 people will experience a major depressive episode at some point in their lives.
The disorder is clinically and etiologically heterogeneous. Despite intense research efforts, the response rate of antidepressant treatments are relatively low and the etiology and progression of MDD remain poorly understood.
To advance our understanding of MDD, we use computational modeling. First, we propose a systematic and comprehensive definition of disease states, which is based on a type of mathematical model called a finite-state machine. Second, we propose a dynamical systems model for the progression, or dynamics, of MDD. We study under what conditions the model can account for the occurrence and recurrence of depressive episodes and how we can model the effects of antidepressant treatments and cognitive behavioral therapy within the same dynamical systems model through changing a small subset of parameters.