According to the National Institute on Drug Addiction (NIDA), methamphetamine has many negative physical effects and impacts on the brain. Some of these may not be reversible.

You don't have to be a scientist to understand that brain imaging and scientific studies have concluded that a meth user is damaged by the drug. The images below, provided by NIDA, depict changes in users' brains, which result in reduced motor speed and impaired verbal learning. Studies have also shown that it may be possible for long-term meth users to become more susceptible to Parkinsonism later in life.