The authors surveyed a sample of psychiatrists, psychiatric residents, internists, general practitioners, and psychologists in Los Angeles County to determine the number of patients with adverse LSD reactions seen by these professionals during an 18-month period. Over 2,000 adverse reactions were reported on, and the authors regard this as a conservative estimate. Although many clinicians feels that the number of adverse LSD reactions is decreasing, the data reported here indicate a substantial increase from the first six-month period to the third.

THE PAST THREE years have witnessed great public and professional concern over untoward reactions from the illicit use of LSD. Several centers have reported series of hospitalized patients with adverse reactions to this drug ( 2, 6 ). Other studies have indicated an increased use of psychedelic drugs by high school and college students( 1 ).

There has been much hysteria and speculation with regard to the actual incidence of adverse reactions to LSD. For example, in the popular literature these statements have appeared: ". . . it is difficult to say what the probability of risk is in a psychedelic experience. . . . Taken at the maximum, with a few hundred in New York City hospitals, several score institutionalized in Los Angeles and the San Francisco Bay Area, and more all around the country, we could have upwards of a thousand hospital visits by acidheads in the next year"( 4 ). And, ". . . one case in 10,000 is going to flip out . . . (but) one episode out of 10,000 LSD cases is no reason for any kind of hand-wringing and grandmotherly panic"( 3 ). There is no mention of the methodology of data collection to support such conclusions.

There are few reported cases of adverse reactions in professional literature. For example, one study states, "by June of 1967 there were 21 reports which contained the details of 225 adverse reactions to LSD. Although this may not include all reported cases, it is believed that coverage is nearly complete"( 5 ).

This study, utilizing a questionnaire, is an attempt to eliminate some of the confusion regarding the incidence of adverse LSD reactions by surveying professionals in a particular geographic area (Los Angeles County) during the 18-month period from July 1, 1966, to January 1, 1968.

Definition of an Adverse Reaction

There is considerable disagreement regarding the definition of an adverse reaction to LSD. For example, we have heard some professionals label any of the perceptual changes that occur after using LSD as "adverse reactions." On the other hand, some advocates of LSD, including professionals, maintain that there are no adverse reactions to LSD.

We made no attempt to impose an arbitrary definition of an adverse LSD reaction on the recipients of the questionnaire. They were asked to report those adverse reactions they had seen on a professional basis in a professional setting. This would prevent individuals from listing as an adverse reaction someone they knew socially or whom they might have seen in a confused state away from their practice setting. Hence, the definition of an adverse reaction was left to the judgement of the professional but was implicitly defined as a drug-induced state which had led individuals to seek professional help.

Methodology
Design of Questionnaire

An 18-part questionnaire was sent to a representative sampling of psychiatrists, psychiatric residents, internists, general practitioners, and psychologists to determine the number of adverse reactions to LSD seen by these professionals in Los Angeles County during the 18-month period from July 1, 1966, to January 1, 1968. Respondents were initially asked whether they had seen any adverse LSD reactions. If the answer was negative, they were asked to answer two questions about the setting of their practice and listing of any other adverse hallucinogenic drug reactions they had seen. If they responded affirmatively, they were asked to check the number of LSD reactions seen monthly for each of the three consecutive six-month period (see table 1) and to complete the questionnaire.

TABLE 1

Wording of the Initial Questionnaire Regarding Number of LSD Reactions Seen per Month

About how many LSD adverse reactions did you deal with per month in the periods of July 1-December 30, 1966, January 1-June 30, 1967, and July 1-December 30, 1967? Please check in the appropriate space provided below. Place an "0" by those that do not apply.

	QUESTION 2. JULY-DEC. 1966	QUESTION 3. JAN.-JUNE 1967	QUESTION 4. JULY-DEC. 1967
None
1-9
10-19
20 or more

The remaining questions were designed to characterize the patient population with respect to age, sex, professional setting where seen, dispositions made, percentage "emotionally disturbed" prior to LSD ingestion, and the percentage of patients with prior bad trips and subsequent flashbacks. The last two questions concerned the number of patients who had adverse reactions from other hallucinogenic drugs.

Sampling

Questionnaires were sent to 2,700 professionals in Los Angeles County. These included all psychiatrists who were listed in the membership rosters of either the Southern California Psychiatric Society or the Los Angeles County Medical Association, all psychiatric residents in Los Angeles County, three-sevenths of the general practitioners and internists listed with the Los Angeles County Medical Society (randomly selected), and three-sevenths of all certified psychologists (randomly selected).

All respondents who had seen an adverse reaction to LSD also received a follow-up letter asking them to list the total number of LSD reactions for each of the six-month periods. As the questionnaires were returned, the answers to the 18 questions were coded on IBM cards and the data tabulated.

Results

Fifty-nine percent (1,584) of the 2,700 questionnaires were returned. There was no significant difference in the response rate of the several professional groups. Twenty-seven percent (428) of all respondents had seen adverse LSD reactions. (Some of this group also reported having seen adverse reactions to other drugs.) Ten percent (163) had seen adverse reactions only to drugs other than LSD, for a total of 37 percent (591) of the respondents reporting adverse drug reactions. Table 2 shows the percentages of each professional group who saw adverse reactions to LSD. Seventy-five percent of the psychiatric residents and 47 percent of the psychiatrists saw adverse reactions, compared to 11 percent of the general practitioners and internists respectively.

TABLE 2

Respondents Who Reported Having Seen Adverse LSD Reactions, by Group

PROFESSIONAL GROUP	PERCENT REPORTING ADVERSE LSD REACTIONS
Psychiatrists	47
General Practitioners	11
Internists	11
Psychologists	31
Psychiatric residents	75

In an effort to avoid overestimating the total number of adverse LSD reactions, we used the smallest possible number of reactions in each category. As an example, if a respondent checked the space for "one to nine" adverse reactions per month, then the number one per month was used for calculating the total reactions seen. If the respondent checked the space for "20 or more" adverse reactions, then the number 20 per month was used for the final calculations. Based on this method of tabulation, the number of LSD reactions for the 18 months was 8,958.

In an effort to double-check the reporting of adverse reactions, we sent a follow-up letter to the 428 respondents who had seen adverse reactions to LSD, asking them to simply list the total number of LSD reactions for each of the six-month periods (table 3). Figure 1 shows the total number of adverse LSD reactions for each six-month period as reported by the 250 respondents (58 percent) who replied to the follow-up letter. Adverse reactions to LSD reported for each six-month period were as follows: July to December 1966 – 613; January to June 1967 – 781; and June to December 1967 – 995. The total number of adverse reactions for the 18 month period as reported in the follow-up response was 2,389.

TABLE 3

Wording of the Follow-Up Letter

Dear Doctor:

Because of the totally unanticipated number of adverse LSD reactions reported, we are making a double check of the recent survey we sent you and would appreciate your answer.

Would you please insert the (approximate) total number of adverse reactions to LSD you have seen during each of the three periods provided in the space below?

Wording of the Follow-Up Letter

Dear Doctor:

Because of the totally unanticipated number of adverse LSD reactions reported, we are making a double check of the recent survey we sent you and would appreciate your answer.

Would you please insert the (approximate) total number of adverse reactions to LSD you have seen during each of the three periods provided in the space below?

JULY-DEC. 1966	JAN.-JUNE 1967	JULY-DEC. 1967

Thank you very much.

Only one and two percent respectively of the professionals reported that a majority of their patients with adverse reactions to LSD were under the age of 15 or over the age of 30. Only 20 percent of the respondents reported that a majority of their patients were females.

Approximately 60 percent of the respondents felt that over half of their LSD patients were emotionally disturbed before they took the drug, as indicated by dropping out of school, inability to hold a job, or having had previous psychiatric treatment. Sixty-one percent of the professionals who had seen adverse LSD reactions reported that none of their patients had experienced the same symptoms prior to using LSD. Twenty-six percent of the respondents indicated that over half of their LSD patients had experienced "flashbacks." Table 4 shows the number of other drug reactions seen. Marihuana topped the list of adverse reactions to other hallucinogenic drugs with a total of 1,887 reported cases for the 18-month period.

TABLE 4

Adverse Reactions to Other Drugs Reported by Respondents

DRUG	NUMBERS OF PATIENTS
Marihuana	1,887
Psilocybin	21
Peyote	85
DMT	101
DET	19
STP	167
Asthmador	145
Other	352

Discussion

Some consideration should be given to interpreting the significance of the incidence of adverse reactions to LSD reported here. In this study "adverse reaction" was implicitly defined as a drug-induced effect which led individuals to seek professional help. We recognize that the professionals' opinions about the various drugs may have been influenced their decisions as to whether or not particular drug-induced states should be labeled as "adverse reactions."

The nature of the following statements by respondents supports this idea: "Patients use such a variety of drug at the same time that it is often difficult to assess which drug is causing the adverse reactions." "From my understanding of the effects, I would consider all reactions to LSD as ‘adverse' regardless of the immediate subjective response."

While it is impossible to say whether the individual biases of the respondents about drugs tended to increase or diminish the number of reported adverse reactions, it is quite evident that the sampling employed in this study contributed to a smaller number of reactions being reported that actually occurred in the community. Those not surveyed included: interns, physicians who are not general practitioners, internists, or psychiatrists; four-sevenths of the psychologists, internists, and general practitioners; and psychiatrists who do not belong to either the Southern California Psychiatric Society or the Los Angeles County Medical Society.

Other professional groups who have had experience with adverse reactions to LSD and were not questioned included: police and narcotics officers, probation officers, ministers, social workers, school counselors, and teachers. In addition, we have seen LSD users in the Los Angeles area who were grossly psychotic for prolonged periods of time following LSD ingestion. Many of these individuals, who were supported by their subculture, were not seen on a professional basis and hence were not included in this study.

It is likely that a number of people with adverse reactions were seen by more than one respondent. It was not possible to estimate to what degree multiple reporting increased the number of reported cases.

As mentioned previously, the initial estimate of 8,958 cases was double-checked by a follow-up questionnaire. Fifty-eight percent of the follow-up questionnaires were returned, reporting 2,389 adverse reactions to LSD in the 18-month period (figure 1). Extrapolating from the follow-up questionnaires, we estimate that if all had been returned the total number of adverse reactions would be approximately 4,100.

FIGURE 1

Adverse LSD Reactions for each Six-Month Period as Reported by 250 Respondents

Number of Adverse Reactions to LSD	Six-Month Period
July-Dec. 1966	613
Jan.-June 1967	781
July-Dec. 1967	995
Total for 18-month period	2389

(Note – In the original article this appeared as a bar chart)

The discrepancy between the 8,958 cases reported by the respondents to the initial questionnaire and the extrapolated figure of 4,100 cases derived from the responses to the second questionnaire is worth consideration. Perhaps some respondents misunderstood the original question, which concerned the number of adverse LSD reactions seen per month in each six-month period (see table 1), and erroneously reported the total number seem in the six-month periods. The follow-up letter requested a listing of the number of LSD reactions seen in each six-month period (see table 3). Several respondents who had initially reported adverse reactions indicated in writing that they were unwilling to reexamine their files and then reported no adverse reactions on the follow-up questionnaire.

Although many clinicians have the impression that the number of adverse LSD reactions is decreasing, our data indicate an increase of 62 percent from the first six-month period to the third (figure 1).

Psychiatrists saw more adverse LSD reactions than did any other professional group. It is interesting to note that a large number of professionals felt that their patients were "emotionally disturbed" prior to using LSD. The psychiatrists tended to see more of their patients as being emotionally disturbed prior to LSD ingestion than did the other professionals; the general practitioners and internists regarded the fewest of their patients as having had a prior emotional disturbance. This might be explained in part by the tendency for psychiatrists to focus more on past emotional development and psychopathology; they are also more inclined to view drug use as symptomatic of emotional difficulty.

The number of professionals who reported that substantial percentages of their patients had experienced "flashbacks" seems to indicate that this phenomenon is fairly common among LSD users. This study does not include individuals who have "flashbacks" but do not consider then disturbing enough to seek professional help. We have attended "LSD parties" and spoken with groups of psychedelic drug users in which many individuals talked about their "flashbacks" as being enjoyable. These individuals described them as being bothersome at times, but they were not inclined to seek professional help.

Many people feel that adverse reactions to marihuana are relatively uncommon. The 1,887 adverse reactions to marihuana reported in this study tend to contradict the opinion that it is an innocuous drug (table 4). In addition, several respondents reported long-term personality changes from marihuana which they did not list as adverse reactions. Other drugs were not nearly so frequently mentioned as producing adverse reactions.

Summary

In this study result are presented of a survey of 2,700 professionals (psychiatrists, psychiatric residents, general practitioners, internists, and psychologists) in Los Angeles County regarding adverse reactions to LSD and other hallucinogens seen in the 18-month period from July 1, 1966, to January 1, 1968. A minimum of 2,389 adverse reactions to LSD were reported.

For a number of reasons, this figure represents a conservative estimate of the total number of adverse reactions which actually occurred. The sampling methods employed contributed to a lesser number being reported. Most physicians and psychologists in Los Angeles County were not surveyed. Other professional groups who have experience with adverse reactions and were not questioned include police, narcotics officers, probation officers, ministers, social workers, school counselors, and teachers. Also, many individuals who have adverse reactions are supported by their subculture and do not seek professional help.

The original questionnaire responses suggested that 8,958 adverse reactions to LSD were seen by the professionals sampled. The revised figure of 2,389 represents the number reported by the respondents who returned the follow-up questionnaire (58 percent). If all respondents had replied to the second questionnaire, the total number of adverse reactions to LSD would be approximately 4,100.

Data characterizing the patient population with regard to age, sex, number "emotionally disturbed" prior to LSD ingestion, the number of prior bad trips, and subsequent flashbacks are also reported. Data characterizing the professional setting in which the patients were seen and disposition made will be presented in subsequent communication.

The respondents also reported on their experiences with adverse reactions to various hallucinogens other than LSD. It is of interest that, despite claims that marihuana is an innocuous drug, 1,887 patients with adverse reactions to it were seen during the 18 months.

REFERENCES

1. Fisher, D. D.: Frequency of Hallucinogenic Drug Use and Its Implications, J. Amer. Coll. Health Ass. 16:20-22, 1967.
2. Frosch, W. A., Robbins, E. S., and Stern, M.: Untoward Reactions to Lysergic Acid Diethylamide (LSD) Resulting in Hospitalization, New Eng. J. Med. 273:1235-1239, 1965.
3. Playboy Interview with Dr. Timothy Leary, Playboy Magazine, October 1966, pp. 110-112.
4. Simmons, J. I., and Winograd, B.: It's Happening – A Portrait of the Youth Scene Today, Santa Barbara, Calif.: Marc-Laird Publications, 1966.
5. Smart, R. G., and Bateman, K.: Unfavourable Reactions to LSD: A Review and Analysis of the Available Case Reports, Canad. Med. Ass. J. 97:1214-1221, 1967.
6. Ungerleider, J. T., Fisher D. D., and Fuller, M.: The Dangers of LSD, J.A.M.A. 197:109-112, 1966.