Brain
Meth causes a large release of dopamine into the brain. Dopamine is a natural neurotransmitter in the brain. High levels of dopamine will cause damage to the nerve endings of the brain. The large release of dopamine also causes its chronic depletion. Low levels of dopamine cause symptoms and the appearance of Parkinson's disease.
Heart
Meth causes the heart to beat extremely fast, which is called tachycardia. This can cause a heart attack, enlarged heart, stroke, and ultimately death. Any damage caused to the heart, from using meth, is not reversible even once meth use is stopped.
Lungs
The lungs are also sensitive to the effects of meth. People will breath faster, medically termed tachypnea, when using meth. This can cause chronic lung damage, severe shortness of breath, and possibly death.
To learn more about the physical side effects of meth, visit our FAQ page.