ACCORDING TO LINDESMITH, INITIAL DOSES OF OPIATES ARE USUALLY BUT NOT ALWAYS PLEASURABLE. AFTER THE FIRST FEW DOSES, UNPLEASANT EFFECTS DISAPPEAR AND PERSONS ENTER EUPHORIA. REPEATED DAILY USE FOR SEVERAL WEEKS RESULTS IN PHYSIOLOGICAL DEPENDENCE, MARKED BY ACUTELY UNPLEASANT PHYSICAL SYMPTOMS WHEN THE DRUG IS NOT USED. SUCH SYMPTOMS ARE KNOWN AS WITHDRAWAL SICKNESS. LINDESMITH'S THEORY CONTENDS THAT, ONCE PHYSIOLOGICAL DEPENDENCE DEVELOPS, CRAVING FOR DRUGS IS FIXED BY NEGATIVE RATHER THAN POSITIVE REINFORCEMENT, BY RELIEF AND AVOIDANCE OF DISCOMFORT AND PAIN RATHER THAN BY POSITIVE PLEASURE. TO TEST LINDESMITH'S THEORY, TWO SURVEYS OF ADDICTS WERE CONDUCTED IN BALTIMORE, MD. TWENTY-TWO ADDICTS WERE RECRUITED FROM STREET GROUPS, AND 16 MORE WERE SELECTED FROM ANOTHER NATURAL ADDICT GROUP. THE REMAINING 26 ADDICTS WERE CHOSEN BY A COLLEGE-EDUCATED EX-ADDICT, KNOWN TO BE RELIABLE. SIXTY OF THE RESPONDENTS WERE MALE AND FOUR WERE FEMALE, AND THEY RANGED IN AGE FROM 17 TO 42 YEARS. WHEN INTERVIEWED, ALL BUT SIX RESPONDENTS WERE USING ILLICITLY OBTAINED OPIATES EXCLUSIVELY. THE AVERAGE AMOUNT SPENT PER DAY ON OPIATES BY EACH ADDICT WAS ABOUT $40. THE SURVEY FINDINGS ESTABLISHED THAT CHRONIC ADDICTS EXPERIENCE EUPHORIA AND EXPERIENCE IT FREQUENTLY. A STATED DESIRE FOR EUPHORIA IS AN IMPORTANT CONSCIOUS MOTIVATION FOR TAKING DRUGS. ADDICTS NOT ONLY DESIRE EUPHORIA BUT ALSO TAKE POSITIVE ACTION TO ATTAIN IT BY CHOOSING OPIATES WITH SUPERIOR EUPHOROGENIC PROPERTIES AND BY USING A GREATER QUANTITY OF THESE DRUGS. SOME OF THE TIME, DESPITE THEIR DESIRES, ADDICTS FAIL TO ACHIEVE EUPHORIC REACTIONS. IT IS CONCLUDED THAT LINDESMITH'S ARGUMENTS DO NOT WARRANT THE EXCLUSION OF POSITIVE REINFORCEMENT FROM THE EXPLANATION OF CHRONIC ADDICTION. SUPPORTING DATA FROM THE BALTIMORE SURVEYS ARE PROVIDED. ADDITIONAL INFORMATION ON ADDICTION IS APPENDED, AND A LIST OF REFERENCES IS INCLUDED. (DEP)