So, while obviously John Sheridan isn’t around anymore after the events of Sleeping in Light – but what about the rest of the cast?
A street drug developed by the very people who are charged with policing it, Dust is a red powder that stimulates telepathic powers in humans (and some other species) for the duration of its use.
Dust was created by the Psi-Corps in an effort to create more human telepaths. It has been an unmitigated failure in that respect, and remains potentially a huge embarassment to the Psi-Corps should its origins become public. In the meantime, the same people who created the drug have the job of hunting down and punishing those who use it.
The fact that the drug works on non-human races, notably the Narn, is most likely indicative of the genetic meddling of the Vorlons with these races, with the drug tapping the telepathic genes implanted by that race.
Related drugs: Psi-blockers
A perfectly legal drug developed by the Psi-Corps in order to suppress the telepathy of those psis who do not wish to join the Psi-Corps.
Psi-blockers take about three hours to take effect after they are administered (via direct injection), although the dosage size seems to affect how long they last for – a standard dose for a registered telepath lasts for a week. Unfortunately, doses that large have the unfortunate side effect of causing depression in long term users (although sociopaths seem immune from this effect).
Related drugs: Dust.