Drugs
From FOnline: Aftertimes
Characters can use drugs, often to enhance combat performance. Chem Reliant characters become addicted to whatever drugs they use, and thus suffer stat penalties between doses. The effects from using drugs only last a while and a timer shows you this. Taking your next round of drugs before a drug timer is done will reset the timer so you don't have to wait until current dose wears off to take the next dose.
Drugs aren't regular food or drinks, unlike consumables. Drugs often cause a strong addiction.