Your body on ice GRAPHIC BY DAVID SWANN AND REPORTING BY CRAIG GIMA / STAR-BULLETIN Click image to return to story. Crystal methamphetamine, or ice, gives the user a feeling of euphoria, but it also damages the brain and can damage the heart, kidneys and intestines. From the lungs to the heart to the brain Smoking ice sends the methamphetamine into the capillaries of the lungs where it is absorbed into the bloodstream, goes straight to the heart and is pumped up to the brain. The effect on the brain is almost immediate. Users get a feeling of euphoria and confidence. But the use of ice can also cause psychosis. Users hear voices or noises. They suffer from anxiety attacks. In some cases the psychosis doesn't go away even after the user stops smoking ice. Ice also constricts blood flow, and an overdose can cause a stroke. The heart An overdose of methamphetamine can cause a heart attack. Methamphetamine is also linked to hypertension and irregular heartbeat. The intestines and kidneys The constriction of blood vessels in the digestive system can damage the intestines, liver and kidneys. Renal failure has also been reported. The high Ice increases the amount of a chemical messenger in the brain called dopamine. Dopamine and even the actual methamphetamine molecule act on nerve endings called receptors in the pleasure centers of the brain. As a result, the user feels a sense of euphoria and self-confidence that can last for hours. Left, a normal brain; right, a brain damaged by ice. The brain damage Brain scans show changes between a normal brain, above, and the brain of an ice user, below. The holes in the ice user's brain are not actual gaps, but show areas of the brain where blood flow is restricted.