Long term alcohol abuse literally shrinks the brain. Post mortems have shown that, in alcoholics, the brain is smaller and lighter than in non-alcoholics of the same age and gender. Non-invasive tests, such as MRI and CT scans have also shown this to be true in living alcoholics.
Similarly, it has been discovered that addiction harms or actually kills cells in the brain. Methamphetamines have been proven to damage cells producing dopamine (a chemical produced in the brain which helps to create feelings of euphoria). Use of the drug can cause ‘aptosis’ whereby brain cells literally self-destruct.
Such changes are almost irreparable. Even after detox and rehab a large percentage of alcoholics retain some level of cognitive impairment. Alcoholism is the second leading cause of adult dementia in the U.S., surpassed only by Alzheimer’s disease.