Stimulant effects in cataclysm dda seem kind of underwhelming to me and some of the effects they have in real life don’t seem to be implemented at all. I know from a bit of digging around that they where nerfed becease they gave way to much of a buff to speed and intelligence spicificly which is why they where nerfed but the current effects that they have of only giving +2 speed and one perception before overdosing seem kind of underwhelming and not representative of how stimulants work. Stimulats are able to raise your athletic and cognative preformence in a number of way from increasing the strength and endurence of athletes, improving reaction time and coordination of martial artist and improving the focus, allertness and wakefullness that people have. The current effects simpely do not reflect this. A minor buff of 1+ to strength and dex (see improved reaction time, coordination and reflexes) and possibly a minor buff to stamina regen or stamina max allong with the current effects would better reflect the effects that stimulats have on athletic preformence. Another point is that stimulants directly increase ones focus and attention which is currently not implemented in the game eventhow this effect is so great that people actually use things like caffiene to improve study preformens and not just to counteract fatigue. This could be reflected by a direct bonus to focus depended on how much stimulant one has (lower levels of stimulants should give this focus bonus and it should possibly decrease at higher stimulant levels) applied on top of whatever focus you already have (something like +10 to 20 focus should do).
I do however think that keeping it so that stimulants don’t raise intelligence is a good idea both for gameplay purpeses (can’t make installing bionics to easy) and becease althow stimulants like caffiene have been shown to increase allertness and focus the effects on things related to intelligence like working memory or reasoning ability have been mixed.
This isn’t really a “bug” per se, as you state it yourself: The “real” and full effects of stimulants are not implemented yet.
Since it has suggested solutions in it, I’ll move it over to The Drawing Board where it probably has a higher chance to be picked up by someone to be worked on.
If you want to make a case for this, you need to dig in a bit deeper and find what the extent of improvement supported by the research is. My understanding from looking into it previously was that it was a few percent improvement at most, which is too small to represent meaningfully in our system.
The focus improvements also might be meaningful, but they also need to be grounded in what the research says happens, not a summary of it.
I did some further digging and you seem correct in that stimulants don’t increase strength by a significant amount.
Every study that I did find on the mental effects of things like caffeine, amphetamine (Adderall) and other psychostimulants did find improvement in mental processes although it varies depending on the doses, the stimulants in question and what mental processes they enhanced. But on the whole the effects where strong enough that all the studies and literary reviews noted improvement to cognitive performance. The mental capabilities that where enhanced the most often seemed to be short-term memory, alertness, attention and focus. It is important to note though that most studies where about lower intake of stimulants and many found that excessively high intake of stimulants actually didn’t further increase of even decreased mental performance.
Given that stimulants as a whole seem to improve memory, attention and focus and the stimulant effect in game is mend to approximate the effects of stimulants as a whole a minor bonus to focus in game while under the influence of stimulants would be justified to approximate this. Something like a bonus to focus that increases with stim level up to something like 10 points around moderate stim levels would be nice to approximate this. With the bonus dropping of/ disappearing if stimulant levels get higher since the studies didn’t go so high in dosage but it also seems that the effects might reverse in some cases.
I find it kind of hard to find studies for dexterity since it isn’t really clear what exactly it is supposed to represent in game but I think it Is meant to represent a bunch of things like reaction time, general motor skill and coordination sense of balance and so on. There is one that I did find with usable data that shows a improvement in reaction time. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3942723/
That reaction time study is exemplary of what I’ve seen elsewhere. If you just read the abstract it shows some promise, but then you get to the specific claims: The reaction time prior to the first combat was significantly lower (−11.9%, P = 0.004) in athletes who had ingested caffeine versus placebo, but this difference was no longer significant after the first and second combats (P = 0.58 and 0.26, respectively, Table 1). The kick time was similar between conditions for all time points (P > 0.05).
So if dosed with caffeine and totally rested, something in the neighborhood of a 12% improvement to one specific input to combat effectiveness, which disappears immediately with a brief combat bout.
That is NOT enough justification to add a combat buff of any kind.