People with a substance use disorder have disturbed thinking, behavior and body functions. Changes in the brain’s wiring are what cause people to have intense cravings for the drug and make it hard to stop using the drug. Brain imaging studies show changes in the areas of the brain that relate to judgment, decision making, learning, memory and behavior control.
These substances can cause harmful changes in how the brain functions. These changes can last long after the immediate effects of the drug — the intoxication. Intoxication is the intense pleasure, calm, increased senses or a high caused by the drug. Intoxication symptoms are different for each substance.