Exploring the Role of Homeostatic Drive in the Perpetuation of Depression and Anxiety Disorders

Background: Feedback mechanisms throughout the brain play a significant role in maintaining physiological homeostasis. Specifically, brain chemicals and neurotransmitters contribute important oversight of psychological activity and homeostatic regulation. We propose that these components form an overarching regulatory system capable of supporting multiple homeostatic regimes. These regimes give rise to psychological behaviors that emerge as a result of the extensive feedback mechanisms involved in neurotransmitter signaling. Methods: Here we explore the possible role of such alternate regulatory programs in perpetuating chronic psychological and mental dysfunction. To do this we represent documented interactions within and between components of the neurotransmitter network as a set of discrete logic circuits. Neuro-transmitter levels are linked to psychological constructs based on current literature. These networks were analyzed via discrete ternary logic and compared to gene expression profiles for subjects diagnosed with depression and post-traumatic stress disorder. Results: Analysis of these regulatory circuits indicated that even in the absence of external perturbations that this model neurotransmitter-psychological network supported two distinct and stable homeostatic regimes. The first corresponds to typical health and behavior, while the second displays depression and anxiety accompanied by decreased serotonin, physical fatigue, and attention, and elevated glutamate, GABA, cortisol, and epinephrine. Conclusion: From this analysis we conclude that the complexity of neurotransmitter- psychological network is capable of supporting alternate homeostatic regimes that are not characteristic of a typically healthy profile, but are nonetheless naturally supported by the circuitry. Furthermore, our analysis suggests that depression and anxiety may be perpetuated under certain conditions at least in part by the brain’s own homeostatic regulation