Physical Effects. Users say meth creates a feeling of euphoria along with increased energy and reduced appetite. A psychostimulant, meth is highly addictive despite, or perhaps, because of the fact that it causes profound and long-lasting damage to the brain.Post-mortem studies link the drug to diseases of aging, including coronary atherosclerosis (hardening of the arteries) and pulmonary fibrosis (scar tissue in the lungs).eth, scientists from the Italian Institute of Technology and UC Irvine say, causes abnormalities in the fat metabolism of cells and this triggers a rise in a type of molecule which promotes cell death. Understanding this, they say they can prevent the drugâs radical effects.