Letters to the Editor
their responses to previous questions. Hence, the purported "retrieval" effect may in large part reflect less than perfect test-retest reliability. This possibility could have been estimated by repeating some of the attitude items in the second questionnaire. On a more conceptual level, it is not clear which survey design (i.e., one versus two questionnaires) yields information on purported behavior that is more predictive of actual behavior. It is possible that respondents who have just contemplated questions about their attitudes will provide more valid responses to hypothetical questions about their behavior. These issues need to be addressed before costly changes in survey strategies are warranted. El Dan Cheikin, PhD BiU Barlow, PhD The authors are with the Group Health Cooperative of Puget Sound. Requests for reprints should be sent to Dan Cherkin, PhD, Center for Health Studies, Group Health Cooperative of Puget Sound, 1730 Minor Avenue, Suite 1600, Seattle, WA 98101-1448.
Reference 1. Beland F, Maheux B, Lambert J. Measurement of attitudes and behaviors in public health surveys. Am J Public Health.
1991;81:103-105.
Beland and Lanmbet Respond We thank Drs. Cherkin and Barlow for the opportunity to expand on our previously published paper on the measurement of attitudes and behaviors.1 Our conclusion was much more prudent than the one attnbuted to us by Cherkin and Barlow. We have clearly stated that though two questionnaires may be needed when attitudes and behaviors toward the same
object are measured, questionnaire design should be examined before it becomes conventional practice to use two questionnaires for such purpose. More precisely, we have suggested that different items, chosen from a pool of reliable items, can be used to measure attitudes and behaviors in a single questionnaire. A mixed strategy can be used whereby similarly and differentlyworded items are chosen to measure attitudes and behaviors. Cherkin and Barlow argued that "the purported retrieval effect may in large part reflect less than perfect test-retest reliability". However, reliability, per se, has nothing todowith time sparing as long as we are measuring the same concept. We think that our results stem from a validity problem.
128 American Journal of Public Health
We are actually in a process of investigating this problem further. Finally, we do not think that our paper is the last word on this matter of measurement of attitude and behavior toward the same object. However, our results pointed to potential problem with the use of similarly worded items for the measurement of attitudes and behaviors toward the same object. We agree, more research is needed and a prudent approach is recommended. l Jean Lambe, PhD Fmnnois Bdand, PhD The authors are with the University of Montreal. Requests for reprints should be sent to Frangois Beland, PhD, University of Montreal, PO Box 6128, Station A, Montreal, Quebec, Canada H3C 3J7.
Reference 1. Beland F, Maheux B, Lambert J. Measurement of attitudes and behaviors in public health surveys. Am J Public Health.
1991;81:103-105.
GlIB Use in South Carolina Gamma hydroxy butyrate (GHB), a central nervous system depressant used in Europe, but not approved for use in the United States, has recently been promoted in weight-lifting magazines and gymnasiums as a body-building supplement. In November 1990, 57 cases of illness linked to the ingestion of illicitly distributed GHB, ranging from drowsiness to respiratory arrest, were reported by US poison control centers.1 To our knowledge, an exposure series of persons using illicitly marketed GHB has not been reported. To determine GHB's availability and range of clinical and adverse effects, we surveyed gymnasiums in three South Carolina cities (Columbia, Myrtle Beach, and Hilton Head), visited those that sold GHB, and interviewed everyone present who used GHB. We asked each GHB user for names of other persons who used GHB and interviewed them. We collected GHB product samples for analysis by the Food and DrugAdministration (FDA). Thiswas done between November 27 and December 10, 1990. Six of 28 gymnasiums contacted sold GHB. We interviewed 22 self-described GHB users, 21 of whom were using a product confirmed to be GHB by FDA
most (64%) began using the drug after October 1, 1990. Seventy-one percent described themselves as regular users; 95% used the dose recommended on the bottle, which was one teaspoon (2.5 g) on most bottles. Eighteen percent mixed GHB with alcohol. No one reported mixing it with any other drug. Reasons for using the drug included body building (55%), to induce sleep (27%), to lose weight (14%), and to achieve a euphoric effect (5%). Effects reported included drowsiness (73%), a high feeling (46%), dizziness (41%), increased sexual arousal (32%), nausea (27%), unconsciousness (14%), and loss of peripheral vision (9%). Two persons (9%) increased the dose to increase its effect. Effects were noted a mean of 15 minutes (range 5 to 30 minutes) after GHB was taken, and lasted on average 2.7 hours (range 45 minutes to 8 hours). Because GHB was available and had notable potentially adverse effects, the South Carolina Department of Health and Environmental Control banned the sale and distribution of GHB within South Carolina on December 13, 1990. Further study of GHB's availability and toxicity as well as the process by which dangerous substances are publicly marketed is needed. El Stephen Luby, MD Jeffiey Jones, MD, MPH Alan Zalewsk4, BS Stephen Luby is with the Centers for Disease Control, Jeffrey Jones is with the South Carolina Department of Health and Environmental Control, and Alan Zalewski is with the Waccamaw Health District. Requests for reprints should be sent to Stephen Luby, MD, South Carolina Department of Health and Environmental Control, 2600 Bull Street, Columbia, SC 29201.
Reference 1. Centers for Disease Control. Multistate outbreak of poisonings associated with illicit use of gamma hydroxy butyrate. MMWR
1990;39:47.
analysis. The average age ofthese 21 userswas 30 years (range 23 to 44). All 22 were White; 73% were male. The earliest reported use of GHB was April 1990, but January 1992, Vol. 82, No. 1
their responses to previous questions. Hence, the purported "retrieval" effect may in large part reflect less than perfect test-retest reliability. This possibility could have been estimated by repeating some of the attitude items in the second questionnaire. On a more conceptual level, it is not clear which survey design (i.e., one versus two questionnaires) yields information on purported behavior that is more predictive of actual behavior. It is possible that respondents who have just contemplated questions about their attitudes will provide more valid responses to hypothetical questions about their behavior. These issues need to be addressed before costly changes in survey strategies are warranted. El Dan Cheikin, PhD BiU Barlow, PhD The authors are with the Group Health Cooperative of Puget Sound. Requests for reprints should be sent to Dan Cherkin, PhD, Center for Health Studies, Group Health Cooperative of Puget Sound, 1730 Minor Avenue, Suite 1600, Seattle, WA 98101-1448.
Reference 1. Beland F, Maheux B, Lambert J. Measurement of attitudes and behaviors in public health surveys. Am J Public Health.
1991;81:103-105.
Beland and Lanmbet Respond We thank Drs. Cherkin and Barlow for the opportunity to expand on our previously published paper on the measurement of attitudes and behaviors.1 Our conclusion was much more prudent than the one attnbuted to us by Cherkin and Barlow. We have clearly stated that though two questionnaires may be needed when attitudes and behaviors toward the same
object are measured, questionnaire design should be examined before it becomes conventional practice to use two questionnaires for such purpose. More precisely, we have suggested that different items, chosen from a pool of reliable items, can be used to measure attitudes and behaviors in a single questionnaire. A mixed strategy can be used whereby similarly and differentlyworded items are chosen to measure attitudes and behaviors. Cherkin and Barlow argued that "the purported retrieval effect may in large part reflect less than perfect test-retest reliability". However, reliability, per se, has nothing todowith time sparing as long as we are measuring the same concept. We think that our results stem from a validity problem.
128 American Journal of Public Health
We are actually in a process of investigating this problem further. Finally, we do not think that our paper is the last word on this matter of measurement of attitude and behavior toward the same object. However, our results pointed to potential problem with the use of similarly worded items for the measurement of attitudes and behaviors toward the same object. We agree, more research is needed and a prudent approach is recommended. l Jean Lambe, PhD Fmnnois Bdand, PhD The authors are with the University of Montreal. Requests for reprints should be sent to Frangois Beland, PhD, University of Montreal, PO Box 6128, Station A, Montreal, Quebec, Canada H3C 3J7.
Reference 1. Beland F, Maheux B, Lambert J. Measurement of attitudes and behaviors in public health surveys. Am J Public Health.
1991;81:103-105.
GlIB Use in South Carolina Gamma hydroxy butyrate (GHB), a central nervous system depressant used in Europe, but not approved for use in the United States, has recently been promoted in weight-lifting magazines and gymnasiums as a body-building supplement. In November 1990, 57 cases of illness linked to the ingestion of illicitly distributed GHB, ranging from drowsiness to respiratory arrest, were reported by US poison control centers.1 To our knowledge, an exposure series of persons using illicitly marketed GHB has not been reported. To determine GHB's availability and range of clinical and adverse effects, we surveyed gymnasiums in three South Carolina cities (Columbia, Myrtle Beach, and Hilton Head), visited those that sold GHB, and interviewed everyone present who used GHB. We asked each GHB user for names of other persons who used GHB and interviewed them. We collected GHB product samples for analysis by the Food and DrugAdministration (FDA). Thiswas done between November 27 and December 10, 1990. Six of 28 gymnasiums contacted sold GHB. We interviewed 22 self-described GHB users, 21 of whom were using a product confirmed to be GHB by FDA
most (64%) began using the drug after October 1, 1990. Seventy-one percent described themselves as regular users; 95% used the dose recommended on the bottle, which was one teaspoon (2.5 g) on most bottles. Eighteen percent mixed GHB with alcohol. No one reported mixing it with any other drug. Reasons for using the drug included body building (55%), to induce sleep (27%), to lose weight (14%), and to achieve a euphoric effect (5%). Effects reported included drowsiness (73%), a high feeling (46%), dizziness (41%), increased sexual arousal (32%), nausea (27%), unconsciousness (14%), and loss of peripheral vision (9%). Two persons (9%) increased the dose to increase its effect. Effects were noted a mean of 15 minutes (range 5 to 30 minutes) after GHB was taken, and lasted on average 2.7 hours (range 45 minutes to 8 hours). Because GHB was available and had notable potentially adverse effects, the South Carolina Department of Health and Environmental Control banned the sale and distribution of GHB within South Carolina on December 13, 1990. Further study of GHB's availability and toxicity as well as the process by which dangerous substances are publicly marketed is needed. El Stephen Luby, MD Jeffiey Jones, MD, MPH Alan Zalewsk4, BS Stephen Luby is with the Centers for Disease Control, Jeffrey Jones is with the South Carolina Department of Health and Environmental Control, and Alan Zalewski is with the Waccamaw Health District. Requests for reprints should be sent to Stephen Luby, MD, South Carolina Department of Health and Environmental Control, 2600 Bull Street, Columbia, SC 29201.
Reference 1. Centers for Disease Control. Multistate outbreak of poisonings associated with illicit use of gamma hydroxy butyrate. MMWR
1990;39:47.
analysis. The average age ofthese 21 userswas 30 years (range 23 to 44). All 22 were White; 73% were male. The earliest reported use of GHB was April 1990, but January 1992, Vol. 82, No. 1
