^ If anything that made dopamine levels rise was neurotoxic, then that would cover sex and I think it's a fucked up evolutionary imperative that makes reproducing your species neurotoxic. Basically it's only going to be of concern with drugs that cause dopamine release (eg amphet, meth, MDMA) rather than plain reuptake inhibitors - well that's my twopennethworth
Hmmm... While I understand what u are saying, and technically u are right, I think this is not a great comparison to make, as it is a bit misleading.
I understand u are saying that just bc something raises dopamine levels, it does not necessarily mean its neurotoxic, since many activities in day to day life which bring joy, also raise dopamine levels, and these things are clearly not neurotoxic.
However, I think a CRUCIAL distinction which must be made is the degree to which many of these dopaminergic drugs raise dopamine levels, as compared to the degree that activities like sex raise these levels. Even the most mind blowing sex will not cause dopamine levels to rise anywhere NEAR what even a mild dose of a dopaminergic drug will. Like most recreational drugs, dopaminergics like MDPV cause a release (or prevent the re-uptake) of chemicals (in this case, dopamine), which occur naturally in the brain. However, it is important to note that drugs like these basically "hijack" your brain, and cause levels of these natural chemicals to reach levels which could never be reached via the simple experiences of day to day life which cause comparatively tiny changes in the levels of these chemicals.
I actually suspect that in response to sexual activity, if your brain was somehow capable of producing a massive flood of dopamine comparable to the levels which the ingestion of something like MDPV can produce, you would likely find that it would result in similar neurotoxic damage. That is to say, I believe the main reason that the rise in dopamine levels in response to something like sexual activity do not cause neurotoxicity, is not due to the "natural" mechanism which causes this rise in dopamine, but simply because the rise in dopamine is so small that it does not cause the neurotoxicity which is seen when something like MDPV causes a far more drastic rise in dopamine.
Ill admit that Im just speculating here, but it seems pretty likely to me.-DG