Three drugs that come from cannabis–marijuana, hashish, and hashish oil–are currently distributed on the U.S. illicit market. These drugs are detrimental to the health and impair the short-term memory and comprehension of the user. When used, they alter the sense of time and reduce the ability of the user to perform tasks requiring concentration and coordination. They also increase the heart rate and appetite. Motivation and cognition can be altered, making acquisition and retention of new information difficult. Long-term users may develop psychological dependence that can produce paranoia and psychosis. Because cannabis products are usually inhaled as unfiltered smoke, they are damaging to the lungs and pulmonary system and contain more cancer-causing agents than tobacco.