Vitamin Five is a popular drug throughout Post-War UK, tailor-made with very specific effects by the infamous drug lord Infinity Dog. Vitamin Five, sometimes known as V5, induces a mental state upon the user which causes them to believe any other drugs they take have a greater effect on them. This was created in order to get more people buying Infinity Dog's drugs.
There was a recorded incident of an overdose of Vitamin Five where a woman believed a box of pills containing Vitamin Five accidentally delivered to her instead of Infinity Dog by the Postman to be rice grains. She boiled the pills (a well-known way of enhancing the effects) & ate them as part of a curry. In the morning, when the Vitamin Five had been completely integrated into her system & at its full effect, she began experiencing wild hallucinations from her tea. She then went into a second overdose from the tea & quickly died.
When The Outsider takes Vitamin Five, all drugs taken afterward have their effects doubled, however Perception & Intelligence are dropped by 1 point. If coupled with the Stoner perk, this makes drug-taking a far better tactic in Post-Apocalyptic Britain.