It's well established that the causality works both ways, i.e. physical illnesses can cause psychological symptoms, and psychological factors can cause physical symptoms, e.g.:
- fever-causing illnesses cause "sickness behaviour" consisting of depression, anxiety, fatigue, brain fog and other symptoms, causing by pro-inflammatory cytokines.
- exam stress has been shown to significantly increase EBV antibodies.
- psychological stress causes significant changes to the immune system through the effects of cortisol and adrenaline (the two main stress hormones are also two of the main immune modulators).
- psychological stress causes a release of TNF-a (a pro-inflammatory cytokine that is involved in sickness behaviour).
- fear causes bowel movements, due to the fact that the HPA axis (the main stress system) also influences bowel motility.
>Attributing a disease to psychological disorder is indistinguishable from saying "we don't understand what causes this."
Not really. If there are factors that point to psychological causation, it should be considered as much as other possible causes.
It might be ultimately reducible in this way, but the treatments for various psychological conditions are often very different than physiological problems.
Just as you can heal a muscle injury with simple rehabilitating exercises, some psychological injuries can be rehabilitated similarly with exercise of the brain. That doesn't change the physicality of it.
