Concering T'Pol's mainlining trellium, I would point to Phlox's complicity in "Damage" in keeping her incapacitation a secret. I was appalled that Phlox would put the entire crew -- not to mention Enterprise's Most Important Mission to date -- at risk to shield T'Pol.
This could be a topic for discussion - in which cases does another objective override the doctor/patient confidentiality, if ever?
While excessive PC is really annoying, I don't think T'Pol's portrayal - from the 3rd season on - is very fair. I gave the example of Azati prime, but the issue is larger than that. Yes, T'Pol has become a drug addict and that's why she fails in the critical moment, but can we imagine Archer becoming drug addict or even Trip, or Malcolm? To begin to take drugs was extremaly irresponsible for a person in T'Pol's position of command in first place and much as I like T'Pol as character I must say that she is portrayed as too much frail personality and too given to temptations. I cannot help suspecting that it is connected with the gender issue, but I suppose its a topic for a separate thread - here we are just offering ideas

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I don't think it is gender, I think it is Vulcan/outsider. "Better than thou" and void of emotion gets seduced by a taste of what her race works so hard to suppress. She spent so much time criticizing humans for their emotions and then got addicted to the drug that let her experience emotions for herself.
Exactly. We can't compare her with Trip or Malcolm or Archer because they're not Vulcans. We might only speculate "would T'Pol get addicted to Trelium-D if she was a male Vulcan character".
For a discussion about gender,
Unexpected and
Stigma B-plot offer a lot of material. IMO they show double standards that ENT writers were not immune to. Trip was practically sexually abused in the former and sexually harassed in the later, and in both cases it was treated as a comedy.
Let's imagine this:
1) Hoshi, while communicating with a race of aliens the ENT has met, becomes friendly and flirts with a male alien; she doesn't go any further - or so she thinks - because she considers it unprofessional and dangerous, but the alien convinces her to participate in a telepathic activity that involves playing in the sand with her hands. A little later, after they part ways with the aliens, she finds out, to her shock, that she is pregnant, even though she has no idea how this could have happened. It turns out that the alien impregnated her - the telepathic ritual was actually the aliens version of reproductive process, even though he never told her what it really was. Everyone on ENT finds it hilarious, and the episode is a lighthearted comedy.
2) Dr Phloxina, ship's Denobulan doctor, is visited by Feezal, one of her three husbands (each of whom have three wives in turn, according to the Denobulan customs). The lively, charming man is completely open about the fact that he finds Hoshi very attractive. He keeps making overt sexual innuendo at her all the time. She is extremely uncomfortable, and tries to avoid him, then she tries to politely let him know that she can't have any kind of relationship with a married man - not to mention that this is someone married to her co-worker. Feezal, however, just smiles and continues with the same behavior. Hoshi worries about Phloxina's reaction, but when she finally comes clean to her, the doctor asks her why she is rejecting her husband's advances, if she dislikes him for some reason or finds him unattractive, then encourages her to go for it. Hoshi is uncomfortable, and explains that she has been brought up to stay away from married men. Phloxina and her husband laugh at the silliness of human sexual morality. This is a comic B-plot.