Psychiatric symptoms as pathogens

Disorders are typically seen as the causes of their symptoms. This makes sense in many fields of medicine, but not
in psychiatry where symptoms constitute disorders: the notion that mental disorders cause symptoms is a tautology.
Biological psychiatry tries to circumvent this logical fallacy by trying to identify pathophysiological parameters that
are specific to given disorders. Unfortunately, research has not resulted in biological markers that reliably discriminate
patients who suffer from a disorder from those that do not. A different approach is to regard psychiatric symptoms
not as ‘output’ from underlying, yet to be identified (pathophysiological) dysregulation, but to consider symptoms as
“input” that causally contributes to other symptoms. Fresh insights, mathematical methods and empirical data come
from network analyses, derived from physics. These network approaches, treating “symptoms as input” converge
with work in Cognitive Behavior Therapy and in Experimental Psychopathology. This convergence is illustrated with
experimental work on Obsessive Compulsive Disorder. It is argued that data and concepts from network theory provide
a sound conceptual rationale for treating symptoms as input and that network theory,