Meth has been called a "double whammy" drug. When using methamphetamine, the user feels energetic and powerful, but a "crash" inevitably follows the "high". In order to avoid or counteract the crash, the user takes more meth. Tolerance develops rapidly, often leading to addiction in a relatively short time.
When meth hits the brain, it causes a chemical reaction to take place. It stimulates the center portion of the brain. That is the portion that regulates our more primitive functions such as the “Fight or flight” reaction of adrenalin, being alert, confident, selfish, self-centered, energetic, and so on. Remember, meth is essentially a stimulant, like coffee is a stimulant. It wakes you up. Meth users, take enough so that the body is overly-stimulated. Way Overly. Stimulation is what causes a meth user to keep craving. Compare it to running on a set of worn out batteries and then being plugged into a wall socket to get the power. Normal life would be rechargeable batteries. Meth is like plugging into 220 volts or even 440. That would be like plugging into four wall sockets at the same time. Talk about being supercharged !
When you have an orgasm your brain sets off between 75-130 dopamine. The first hit of Meth sets off about 1200-1500 dopamine. Now you can see why it is so hard to stop after the first hit.