I wonder if for some of these drugs it may not be a tolerance effect, but perhaps the drugs are just doing what they are going to do (a long-term physiological change) and after that point no longer have an effect. Like growth hormones after bone plates have fused.
Most of those do not affect neurogenesis (some exceptions apply), but some can be outright neurotoxic chronically, potentially by excitotoxicity. Which means oxidative stress on neurons impairing their function.
A bunch of strong serotonergics produce such effects. Normally SSRI are screened for it, but that's mostly for acute version...
Dose scheduling is underresearched part of the whole ordeal. Sometimes a pause is necessary to prevent the damage or recerse the tolerance.
