MOST RESEARCH INDICATES THAT MARIHUANA IS HARMFUL TO USERS. THE USE OF MARIHUANA AND OTHER DRUGS DISRUPTS ELECTROCHEMICAL PROCESSES OF THE BRAIN AND NERVOUS SYSTEM AND DISTORTS SENSORY INFORMATION RECEIVED BY AND EMOTIONAL RESPONSES OF USERS. STUDIES OF CHRONIC USERS INDICATE THAT THEY SUFFER FROM DIMINISHED DRIVE, LESSENED AMBITION, DECREASED MOTIVATION, AND APATHY. MODERATE USE ALSO HAS ENDURING AND DEBILITATING EFFECTS. REGULAR USERS SHOW EVIDENCE OF A CONTINUING LOW-GRADE INTOXICATION MANIFESTED BY MOOD SWINGS, MEMORY IMPAIRMENT, SLEEP DISTURBANCES, AND A GENERALLY LOWER LEVEL OF FUNCTIONING. SOME OF THE MORE PERSISTENT EFFECTS OF MARIHUANA USE ARE DEFECTIVE MOTOR COORDINATION AND POOR PERCEPTIONS OF TIME, DISTANCE, AND SPEED. PERSISTENT EXPOSURE TO MARIHUANA RESULTS IN SIGNIFICANT INCREASES IN CHROMOSOME BREAKAGE. HISTORICAL TRENDS INDICATE THAT, WHEN DRUGS ARE READILY AVAILABLE, THEIR USE INCREASES. ONE OF THE METHODS USED TO DETERMINE THE AMOUNT OF ANY DRUG AVAILABLE TO POTENTIAL USERS IS TO EXAMINE THE AMOUNT SEIZED BY LAW ENFORCEMENT PERSONNEL. IT IS A COMMONLY HELD OPINION THAT ONLY 10 PERCENT OR LESS OF THE AMOUNT AVAILABLE TO THE COMMUNITY IS SEIZED. THE DECRIMINALIZATION OF MARIHUANA IS NOT SUPPORTED BUT RATHER IS VIEWED AS A FIRST STEP IN LEGITIMIZING THE USE OF SUCH OTHER DRUGS AS COCAINE. THE EXPERIENCE OF CALIFORNIA IS CITED AS AN EXAMPLE OF THE FAILURE OF DECRIMINALIZATION IN REDUCING DRUG USE AND CHANGING HUMAN BEHAVIOR. DECRIMINALIZATION WOULD HAVE THE ADDITIONAL AFFECT OF WEAKENING OUR INTERNATIONAL EFFORTS, ESPECIALLY WITH MEXICO, IN CONFRONTING THE INTERNATIONAL DRUG TRADE. IT IS CONCLUDED THAT MODERATE CRIMINAL SANCTIONS CAN BE EFFECTIVE IN BRINGING ABOUT DESIRED PUBLIC BEHAVIOR AND THAT DECRIMINALIZATION OR LEGALIZATION OF MARIHUANA WOULD SIGNIFICANTLY INCREASE MARIHUANA ABUSE. (DEP)