Almost everyone drinks coffee, right? Well, the beverage’s active ingredient is caffeine, which is the most commonly consumed psychoactive substance in the world. Not only is caffeine found in coffee, but it comes in tea, chocolate, soda and many other items we eat and drink, which is why it’s hard to abstain from it. A Gallup poll in 2015 found that nearly two-thirds of adult Americans drink at least one cup of coffee a day.

3. Alcohol

Alcohol is a depressant that initially makes the user happy and less reserved, while also dulling most pain. Excessive alcohol consumption impairs judgment and depth perception, and can cause drowsiness, excessive rage, unconsciousness and even blackouts. Long-term alcohol use can lead to liver and nerve damage, sexual problems, high blood pressure, permanent brain damage and deterioration of motor skills.

4. Nicotine

About one-third of people who inhale or ingest nicotine end up getting addicted. Once that happens, it’s very difficult to give it up, as anyone who has tried to quit smoking will readily admit. Nicotine is subsequently a stimulant and a relaxant. It induces a pleasant, happy sensation, while also providing a rush of adrenaline, increasing the heart rate and blood pressure.