There are a variety of drugs a character can use.

They are split into multiple categories and you can only use one drug of each category at a time.

Class A Drugs

These Drugs last for 60 minutes and their purpose is to enable a character to better fulfill a role that it was not optimized for.

In general, these drugs come with great disadvantages and a true sniper will always perform better in a sniping role than a drugged brawler. This is not always the case, and Min-Maxing is a viable effort one can do in order to make Drugs further optimize your role.

Class B Drugs

These Drugs last for 2 minutes, they too have strong positive as well as negative effects, however, in addition to the much shorter time-frame they work on, they usually have a 30 second withdrawal phase after the drug effect ends, which further weakens your character during those vulnerable moments.

Class C Drugs

These Drugs last only for 15 seconds and usually have some very devastating effects. Most drugs in this Category are Nuka Colas.