Effect:
Suppress brain activity, promoting relaxation, sedation, and sleep.
Examples:
* Alcohol
* Benzodiazepines (e.g., diazepam, lorazepam)
* Barbiturates
* GHB (gamma-Hydroxybutyric acid)
* Sleeping pills (e.g., zolpidem)
Effect:
Enhance brain activity, increasing energy, focus, and wakefulness.
Examples:
* Amphetamines (e.g., Adderall, methamphetamine)
* Cocaine
* Caffeine
* Nicotine
* Modafinil