When it comes to doing drugs, just say no. (Or yes. Or waffle a bit, have a couple of drinks, then say yes.) When it comes to putting drugs in your movie, however, think long and hard about that particular decision; if after that you still must, then at least consult with someone who's done that drug before. Ask questions. Find out how the drug makes you feel. Inquire as to how long it takes to hit, and how long it lasts and what the possible negative side effects might be. I bring it up because a number of depictions of drug use in recent releases have struck me as false. Consider the following cases:
1. [SPOILER LEVEL: MEDIUM] In Pedro Almodóvar's Broken Embraces, actor Tamar Novas plays an assistant to a film director, who also moonlights as a DJ at a nightclub. Drugs are pushed his way a lot, and one night, he dabs his finger in some powdered ecstasy and places it on his tongue. Another character saunters up and puts a glass of Coke down in front of him that's laced with GHB. Novas's character sips from the wrong glass accidentally, and instantly after the drink passes through his lips, he lapses into a coma.
Misinformation Level: High. It would take longer, and he would have to have ingested more of the drug, to induce a coma. Drinking alcohol would have contributed to the dangers, but he does not appear to be drinking in the scene.
2. [SPOILER LEVEL: LOW] In Mike Judge's Extract, Ben Affleck's character is a big proponent of pharmaceutical and recreational drugs. He offers Jason Bateman's character an anti-anxiety medication, then later realizes the pill he gave his friend was actually Ketamine, an animal tranquilizer also used at triage stations on the battlefield for its disassociative properties -- it gives the user an "out of body" experience. Bateman's character hires a gigolo to seduce his wife while under its influence.
Misinformation Level: Medium. The character showed none of the typical characteristics of someone on Ketamine, or Special K, as it's called in clubs. The effects may have worn off, but there's no obvious connection between the drug and his poor judgment in the scene in question.
3. [SPOILER LEVEL: HIGH] In Grant Heslov's The Men Who Stare at Goats, soldiers at an army base in Iraq that houses a paranormal studies unit are fed LSD in their morning rations. They soon take on stereotypical "flower-child" characteristics -- communing with nature, smiling, sitting down at their lookout posts and swinging their legs blissfully, etc.
Misinformation Level: High. For a film that prides itself on being based on fact, the reaction of the soldiers to being unwittingly drugged with a strong hallucinogenic like LSD would have more likely been paranoia, anger, fear and anxiety.
4. [SPOILER LEVEL: NONE] In Michael Bay's Transformers: Revenge of the Fallen, a pot brownie turns Shia LaBeouf's character's mother into a horny, campus terrorizing freak.
Misinformation Level: Low. That's exactly what pot brownies do to your mother.