It’s way more complicated than that. The diagnostic criteria changes over time, for many diseases with psychological components, in ways that make formerly pathological behaviors now healthy and vice versa.
Placebo doesn’t actually help you, obviously, despite what the outcome you’re measuring suggests. It represents a slack (something not quite an error, but not quite a useful measurement) in the outcomes based measurement regime. It’s a “cosmological constant” as a side effect of the limitations of enumerating causal and contributing factors.
People believe acupuncture is a placebo, and in an evidence based medicine regime it seems reasonable to prescribe it. But it depends what you’re calling pathological. Today, a population of video game players versus a control will score better on many psych outcomes. Tomorrow, they’ll change the tests, subtly, to account for “factors” better, and the results will reverse. The USMLE study book in 2018 pathologizes “video game fixation” (they can’t call it an addiction) before such a test change has occurred. The simple rule is that whatever society determines to be pathological will trickle down to the field of medicine, and placebo effects are the loudest signal of the limitations of an otherwise most superior way to administer therapies.