Drugs interfere with the brain's ability to take in, sort, and synthesize information. As a result, sensory information runs together, providing new sensations while blocking normal ability to understand the information received. Research shows that drugs erode self discipline and motivation necessary for learning that causes decline in academic and work performance as well. The marijuana produced today is from 5 to 20 times stronger than that available as recently as 10 years ago. Research has shown that severe psychological damage, including paranoia and psychosis, can occur when marijuana contains 2 percent THC, its major psychoactive ingredient.
Alcohol consumption causes a number of marked changes in behavior.
Even low doses significantly impair the judgment and coordination required to drive a car safely, increasing the likelihood that the driver will be involved in an accident. Low to moderate doses of alcohol also increase the incidence of a variety of aggressive acts, including spouse and child abuse. Moderate to high doses of alcohol cause marked impairments in high mental functions, severely altering a person's ability to learn and remember information. Very high doses cause respiratory depression and death. If combined with other depressants of the central nervous system, much lower doses of alcohol will produce the effect just described.