Tobacco Tobacco is linked with more serious health problems than nearly all other psychoactive drugs. Tobacco causes an estimated 350,000 deaths in the United States per year. Nicotine produces constriction of blood vessels, loss of appetite, and a sharp rise in blood pressure and heart rate. Potency of the substance varies greatly, and plants may be sprayed with agents that pose significant health risks to the user. Marijuana raises heart rates and lowers blood pressure, causing reddening of the eyes.
Psychological dependence is a common problem.
High dosage or chronic use can trigger panic and anxiety in some users. Regular use interferes with learning and concentration, resulting in low motivation and further dependence on the drug. Marijuana can have a serious effect on pregnancy. Women who smoke marijuana during pregnancy may give birth to babies with defects similar to those seen in infants born with fetal alcohol syndrome for example, low body weight and small head size. The most potent stimulant found in nature, cocaine is extracted from the leaves of the coca plant.