So some people decided in advance that the cause must be nutritional, or toxic, or Imbalance, or drug side effect, or whatever, and they search for a cause that fits that agenda. Even doctors do this. The right approach is to list ALL of
the possible causes, organize them according to likelihood, eliminate the ones that don't fit, test for the ones that might fit, and then the one that is left over is the one. This is called "making a differential diagnosis".