As the net result of molecular activities, alcohol functions as a depressant much do the barbiturates and the benzodiazepines, with which alcohol has some cross_dependence. At the level of 0.05 percent alcohol in blood, thought, judgment and inhibitions are loosened and sometimes disrupted. At the concentration of 0.1 percent voluntary motor actions usually become perceptibly clumsy.
In the most States of USA, legal intoxication ranges from 0.1 to 0.15 percent blood alcohol level. At 0.2 percent, the function of entire motor area of the brain is measurably depressed, and the parts of the brain that control emotional behaviors are also affected. At 0.3 percent a person is commonly confused or may become stuporous; at 0.4 to 0.5 percent, the person falls into coma. At higher levels, the primitive centers of the brain that control breathing and heart rate are effected, death ensues secondary to direct respiratory depression or the aspiration of vomitus.