Drugs

Drugs are an important aspect in the GTA series. Drugs take place in every single Grand Theft Auto game, they are sold, bought (for others), and used by characters around the protagonist on many occasions. 

Adrenaline in the GTA III era games were sometimes mentioned as drugs by GTA fans, there was also a deleted feature where in GTA San Andreas, Carl Johnson would be able to smoke weed which would make the camera wobble around making hard to control CJ.

In Grand Theft Auto: Chinatown Wars the protagonist Huang Lee can control stocks of drugs and buy them and sell them to other drug dealers which is a good way to make money. There are 6 types of drugs the player can deal Cocaine,  Heroine, Downers, Acid, Marijuana, and Ecstasy

In GTA Vice City Stories you could make business empires for drug manufacturing and distribution.

You can also sell drugs in GTA Vice City while driving the Cherry Popper Ice Cream Factory truck.

Protagonists

It should also be noted that all of Grand Theft Auto's protagonists are against using drugs, though they frequently deal with them on a business level. Protagonists are never seen doing drugs, and when offered, deny it.

• One of the main premises of GTA San Andreas is getting crack, crack heads, and crack dealers out of Los Santos to make it a better place.

• Carl Johnson denies an offer for a bong hit from Tenpenny

• Vic Vance despises drugs and is extremely uncomfortable even dealing with them.

• Niko Bellic denies a toke of marijuana from Little Jacob on many occasions.

Accidental Drug Use

• In GTA San Andreas, Carl Johnson is helping The Truth dispose of his marijuana fields by burning them, which in turn gets Carl high and disrupts his basic motor skills

• In GTA Vice City Stories Vic Vance is in a car accident with a van full of a marjuanna known as Purple Haze. This causes Vic's sight to narrow and blur with purple. His motor skills are also highly effected.

Cocaine Use

GTA Vice City

• Sonny Forelli sets up a deal with the Vance Crime Family in 1986 for 2 million dollars worth of cocaine, only to have the deal ambushed by Ricardo Diaz's men.

• Ken Rosenberg (the laywer for Tommy Vercetti) is addicted to cocaine.

• Ricardo Diaz is usually high on cocaine, or using cocaine while meeting with Tommy Vercetti.

GTA San Andreas

• Big Bear is addicted to crack cocaine.

•  Ken Rosenberg is rehabilitated and off of cocaine.

•  Ken Rosenberg starts abusing cocaine again.

GTA Vice City Stories

•  Lance Vance is a frequent user of cocaine, and possibly addicted.

• Louise Cassidy-Williams is a cocaine user and possibly addicted.

Grand Theft Auto IV

•  Elizabeta Torres is a frequent cocaine user.

•  Elizabeta also had cocaine stolen off of her, she had Niko Bellic retrieve it, although he was cut of by police, and Elizabeta ended up in jail on 10 charges of cocaine distribution, 30 years each leading to her 300 year sentance.
• Packie McReary also is a frequent cocaine user.
• In The Ballad of Gay Tony, there are many cocaine users including Gracie, Evan, and Rocco.

GTA Chinatown Wars

•  Huang Lee can buy and sell cocaine.

 

Marijuana Use

GTA San Andreas

* Many of the Grove Street Families smoke marijuana

•  Ryder is almost always seen with a blunt

• The Truth is a frequent marijuana user.

• The Truth also has his own fields of marijuana, which is later burned down by Carl Johnson to save Truth from jail time.

GTA Vice City Stories

* Victor Vance has to deliver a van full of a type of marijuana known as Purple Haze, which after he's ambushed, is accidentally drugged effecting the gameplay.

GTA IV

• Little Jacob is almost always seen smoking marijuana.

• Real Badman also smokes marijuana with Little Jacob

• Niko allows Little Jacob to smoke marijuana in a helicopter during a mission for the U.L. Paper, as to calm his nerves secondhandedly.

GTA Chinatown Wars

•  Huang Lee can buy and sell marijuana.