FLYING HIGH:
THE AEROMEDICAL ASPECTS OF MARIHUANA

Introduction.

In June 1972, the Office of Aviation Medicine,
AA, sponsored a Symposium on Aeromedical
spects of Marihuana at the Civil Aeromedical
stitute in Oklahoma City, Oklahoma. Most of
e formal papers presented at that symposium
e available elsewhere: This paper summarizes
iterial relevant to aviation medicine presented
the formal papers or in the informal panel
scussions. Much of the latter developed from
estions submitted to the panel from representa-
‘es of the aviation community.

. Legal Aspects.

Use of marihuana by an individual does not
itself constitute grounds for denying an FAA
sdical certificate. Under the FAA medical
gulations (Part 67), drug dependence (i.e., an
‘ablished diagnosis of drug dependence) is dis-
alifying for all classes of certification. A his-
cy of occasional, experimental use of marihuana
not, of itself, disqualifying unless there has
en a personality disorder that is severe enough
have repeatedly manifested itself by overt acts.
Jditionally, a certificate may be denied by the
sderal Air Surgeon if he determines that a per-
nality disorder makes the applicant unable to
rform safely the duties of an airman, or if the
sderal Air Surgeon finds that the disorder may
isonably be expected to make the applicant
able to perform those duties within two years
ter the finding.
FAA regulations (Parts 61.15, 63.12, and
.12) state that no person who is convicted of
slating any Federal or State statute relating
the growing, processing, manufacture, sale,
sposition, possession, transportation, or impor-
ion of narcotic drugs, marihuana, and depres-
at or stimulant drugs or substances is eligible
v any certificate or rating . . . for a period of
e year after the date of conviction. Addi-
mally, FAA regulations (Part 91.12) hold that
person may operate a civil aircraft within the

United States with knowledge that narcotic
drugs, marihuana, and depressant or stimulant
drugs or substances as defined in Federal or State
statutes are carried in the aircraft, unless that:
carriage is authorized by or under any Federal
or State statute or by any Federal or State
agency.

The Aeromedical Certification Branch of
CAMI currently processes about 500,000 appli-
cations for medical certificates annually. The
accompanying histories contain questions about
the use of drugs. During the last three years, a
small but significant number of applications
(approximately 500 out of a total of about
1,000,000 in a two-year period) has been processed
in which the applicant has admitted to previous
use of marihuana. Such individuals have ad-
mitted to a crime, an admission that is carried
in FAA records and that may prove potentially
dangerous to those individuals in the future un-
less the confidentiality of individual records is
protected. At the time of the symposium this
issue had not been resolved.

One question frequently raised at the FAA’s
AME seminars is “Do you think in another five
years or so we'll have an eight-hour rule for
marihuana as we have for alcohol presently?” A
similar question was posed to the panel: specifi-
cally, in the event that the private use of mari-
huana is decriminalized, as suggested by the
National Commission on Marihuana and Drug
Abuse, what is the minimum interval which must
elapse before the user may be permitted to engage
jn aviation-related activities? This question pro-
voked considerable discussion about the difficulty
in defining what for each individual may be dif-
ferent. Obviously, a safe limit would be one
week, since all of the drug is metabolized and
disposed of by the body in this time interval.
Although periods of 8 to 12 hours were suggested
the panel was unable to agree upon a reasonable
minimum period based on current data. Taken
orally, the drug is still active up to 12 hours. If





stances. Dornbush related that in a study in
ece of very heavy hashish users the “flash-
x” phenomenon was never reported. Reports
flashback may be due partly to learning.
wmacologically, the flashback phenomenon
sn’t exist for marihuana.
-mong the other myths refuted was the claim
; marihuana users tend to avoid alcohol. It
pointed out that although early reports based
surveys of older users suggested that the
’s did not drink while smoking marihuana,
‘e recent data indicate that there is a rising
rest in the combined use of alcoho] and mari-
na. The effects of such combined use have not
1 definitively elucidated.
nother question concerned marihuana’s repu-
on for being an aphrodisiac. Ferraro cited
orts from surveys of marihuana smokers in
ch it was reported that they were less likely
nitiate sexual activity while using marihuana,
once sexual activity was initiated, enjoyment
augmented. Ferraro attributed this latter
ot to the overestimation of temporal intervals
; the drug produces; the man feels he’s won-
ful during intercourse, because ten minutes
a more like an hour.
sa final myth, some mention must be made
he marihuana “high.” Barratt was convinced
; 50% of the people who say that they get
1 on marihuana never get physiologically
a. They get a social high. Lewis® has as-
ed that in the absence of evidence that mari-
na use is self-sustaining, we must conclude
; marihuana use is sustained principally by
social reinforcement provided by the milieu
he “pot party” and that this social reinforce-
it may be sufficiently powerful to transform
it may be an unpleasant or neutral drug effect
an apparently pleasant stimulus condition ;
rather than being a primary reinforcer, mari-
na is a conditioned reinforcer that derives
power from the potent reinforcements pro-
ad by social interactions. Thus, the “social
7” is an individual’s production of the external
1s of marihuana use to obtain social reinforce-
it in the absence of reinforcement provided by
drug. Lewis® explains the lassitude and
thy of the heavy marihuana user’ as being,
part, due to the acquired reinforcing power
he drug, a power that is socially maintained
vite wide fluctuations in the potency of the
ilable drug supply.

VII. Marihuana and Civil Aviation.

The primary question asked of the panel con-
cerned the need to develop rational aeromedical
policies, in the event that the recommendations
of the National Commission on Marihuana and
Drug Abuse to decriminalize the private use of
marihuana may be made into law. For example,
how much marihuana use is unsafe? The panel
agreed that there was no rational method for de-
fining safe use. For one thing, the casual mari-
huana user who makes purchases in the street
cannot tell in advance what the THC content of
the marihuana he buys will be and, in fact, a lot
of it has been dipped in opium. One member
of the panel suggested that use be defined in terms
of the number of times an individual gets high,
since most marihuana users titrate themselves in
terms of smoking; i.e., they smoke until they are
high and then stop. However, when pressed to
define a high, this researcher could define the term
only as the point at which the user stopped smok-
ing, a definition that was, admittedly inadequate.

Earlier, we mentioned the lack of agreement
about the minimum time that should elapse be-
tween marihuana use and work in aviation-re-
lated activities. While the panel was unable to
suggest a definite number of hours, many mem-
bers felt that something of the order of 12 to
16 hours would be appropriate.

Another question concerned the effects of mari-
huana on performance under emergency condi-
tions. Citing studies of shock avoidance in
animals, one researcher stated that since these
behaviors seem to be fairly resistant to the effects
of A°-THC, very high doses had to be taken be-
fore performance deficits would occur. Other
members of the panel felt that the behavior in
question had to be more clearly defined before
any generalizations could be made.

The panel was asked if pilots who volunteered
to participate in controlled studies of the use of
marihuana on flying proficiency, either in-flight
or in simulated flight, should be grounded for
the duration of the study and/or for any period
thereafter. The panel generally agreed that there
would be good reason for grounding participat-
ing pilots during the study. Since restrictions
would have to be placed on these subjects, such
as restricting their alcohol intake, grounding
them would be advisable; and by observing them
during the study and by making post-drug tests,



a distinction is made based upon route of admin-
istration, the panel seemed to agree that safe
minimum intervals would be: 8-12 hours, if
inhaled; 12-20 hours, if ingested. The panel
agreed that specification of a reasonable minimum
period would be controversial at this time.

III. Military Experience.

Two papers discussed the impact of marihuana
use on military aviation. Lt. Col. William H.
Hark (U.S. Army) reported that a 1969 field
survey of flight surgeons suggested that the use
of marihuana occurred primarily among rear
support units and rarely involved actual flying
personnel. No evidence of maintenance impair-
ment attributable to marihuana was found and
no aircraft accidents were attributed to mari-
huana use among Army personnel.

Capt. Victor M. Holm (MC, USN) reported
a paucity of data relating marihuana use to
Naval aviation. Only a few cases were isolated
and it was felt that the rigors of training and
of operational tours act to deselect chronic mari-
huana users. While stressing the need for careful
appraisal of individual cases, Capt. Holm con-
cluded that there was no evidence to indicate
that previous experimentation with marihuana
should be grounds for disqualification.

IV. Acute Effects,

Generally, the acute effects of marihuana in-
cluded disruption of both simple and complex
performance tasks. One researcher® reported a
biphasic phenomenon: at low doses. marihuana
appeared to have excitatory effects, while at high
doses the drug was a depressant. Both Ferraro?
and Dornbush* reported studies in which mari-
huana (or the principal active ingredient,
A°-THC*) produced decrements in short-term
memory. Dornbush ascribed these memory de-
crements to disruptions produced by the drug
during the encoding phase.

Moskowitz’ reported that marihuana produced
deficits in peripheral signal detection, as well as
very large effects on autokinesis. He obtained no
effects on visual acuity, dark adaptation. or ver-
tical phoria, but found a pronounced influence

* Although it is the principal active ingredient, A THC
is only one active ingredient found in the marihuana
plant. A*THC, for example, is also psychoactive, but not
to the same extent as A’.

on lateral phoria, a result that may be relat:
to the autokinetic effects of the drug.

Halls described research that strongly sugges
that the effects of marihuana may be augment:
by conditions of hypoxia.

V. Chronic Effects.

A large part of the research reported at t
symposium was concerned with the developme
of tolerance to marihuana. Tolerance may
defined as a return of a dependent variable
baseline levels upon repeated administrations
a constant drug dose following an initial chan
in the baseline when the drug is first admi
istered, or as the maintenance of a recover
baseline (following initial disruption when t
drug is first given) with increments in chror
drug dose.

There was general agreement that the effe
of marihuana on simple behaviors demonstr:
a rapid development of tolerance. MeMill
demonstrated that tolerance can develop to su
an extent that changes in the lethality of t
drug are observed.’ Nevertheless, some behavic
are remarkably resistant to tolerance. Th
Ferraro found that short-term memory remain
disrupted during chronic administration
A°*-THC.

Benjamin surveyed research concerning ma
huana users and driving; although the evider
did not indicate that marihuana use increas
accident rates, there was evidence that drivi
ability may be impaired by use of marihuana

VI. Some Myths.

The panel was most emphatic in debunki
many of the myths that have been propagat
about marihuana use. Thus, while there was
disagreement about “flashback” experiences
curring with other drugs (ie., with some dru
such as LSD, the users report experiences
drug-like effects that occur some time well af
the initial drug-produced experiences have ¢
appeared and, importantly, in the absence of :
ditional drug taking), the panel agreed that
“flashback” phenomenon was very unlikely
marihuana. Indeed, it was suggested that
ports of a “flashback” phenomenon by marihu:
users were probably due to the adulteration
the “marihuana” purchased on the street.
ports were cited of marihuana being adultera
with LSD, mescaline, peyote, and various ot


REFERENCES

cewis, M. F.: Current Research in Marijuana, New
Tork, Academic Press, 1972, 219 pp.

‘erraro, D. P.: Effects of A’Trans-Tetrahydrocanna-
inol on Simple and Complex Learned Behavior in
animals, Current Research in Marijuana, New York,
icademic Press, 1972, 49-95.

{eMillan, D. E., and W. L. Dewey: On the Mechanism
f Tolerance to A*THC, Current Research in Mari-
wana, New York, Academic Press, 1972, 97-114.

Yornbush, R. L., G. Clare, A. Zaks, P. Crown, J.
‘olavka, and M. Fink: 21-Day Administration of Mari-
uana in Male Volunteers, Current Research in Mari-
wana, New York, Academic Press, 1972, 115-128.

foskowitz, H., S. Sharma, and M, Schapero: A Com-
arison of the Effects of Marijuana and Alcohol on

na

~

Visual Functions, Current Research in Marijuana, New
York, Academic Press, 1972, 129-150.

. Hall, P., J. W. Fitch, V. J. Riegel, and J. B. Best:

Effects of Altitude and Psychological Stress on the
Response of the Rat to Cannibolic Compounds, Current
Research in Marijuana, New York, Academic Press,
1972, 151-162.

. Barratt, E,, W. Beaver, R. White, P. Blakeney, and

P. Adams: The Effects of the Chronic Use of Mari-
juana on Sleep and Perceptual Motor Performance in
Humans, Current Research in Marijuana, New York,
Academic Press, 1972, 163-193.

. Lewis, M.: Marijuana Today: An Overview, Current

Research in Marijuana, New York, Academic Press,
1972, 215-219.



TECHNICAL REPORT STANDARD TITLE PAGE

% Government Accession No. 3. Recipient's Catalog No.

Report No.

FAA~AM= 73-12
Title and Subtitle

5, Resort Date

December_1973

6, Performing Organization Code

FLYING HIGH: THE AEROMEDICAL ASPECTS OF MARIJUANA

Author(s)

8. Performing Organization Report No.

Mark F. Lewis, Ph.D., and Douglas P. Ferraro, Ph.D.
Performing Organization Nome and Address

7AA Civil Aeromedical Institute

2. 0. Box 25082 Ti. Contract or Grant No.
Jklahoma City, Oklahoma 73125

10, Wark Unit No.

TS. Type of Report and Period Covered

+ Sponsoring Agency Name and Addres=
JEfice of Aviation Medicine QAM Report
tederal Aviation Administration
300 Independence Avenue, S. W.
Jashington, D. C. 20591

+ Supplementary Notes
this research was conducted under Task No. AM-B-73-PSY-25.

14. Sponsoring Agency Code

y Abstract

\ summary of the discussions from the CAMI Symposium on Aeromedical Aspects of

farihuana is presented. The invited panel discussed the legal aspects of marihuana

ase and aviation, the experiences of military aviation, and the acute and chronic

2ffects of the drug. For civil aviation, the panel proposed: (1) a 12-16 hour

seriod between marihuana use and work in aviation, (2) no radical changes in

?AA policy towards marihuana use, and (3) additional research on aeromedical

aspects of marihuana.

18. Distribution Statement

Key Words
Availability is unlimited. Document may
ee le dicine be released to the National Technical
bert cpa ce we Information Service, Springfield, Virginia
riorman 22151, for sale to the public.
"Security Classif. (of this report) 20. Security Classif. (of this page) TI. No, of Pages | 22. Price
Unclassified Unclassified 5 $3.00

tm DOT F 1700.7 (8-69)







the researcher could determine when it became
safe for the pilot to be returned to flight status.

Finally, the panel was asked if the FAA should
conduct research on the aeromedical aspects of
marihuana. Here, there was complete agree-
ment, All panel members felt that the academic
community was not equipped to extend itself
into this area of interest. Therefore, the FAA
should perform the research required.

VII. Recommendations of the Panel.

1. The panel would not recommend any rad
changes in FAA policy with respect to m
huana use, at the current time.

2. The panel suggested that a 12- to 16-1
period between marihuana use and work in a
tion activities would not be unreasonable.

3. The panel recommended that the FAA
gage in research on aeromedical aspects of m
huana.

Appendix I
Members of the Symposium Panel

E, Barratt, Behavioral Science Laboratory, Department
of Neurology and Psychiatry, The University of Texas,
Galveston, Texas.

Fred B, Benjamin, Research Institute, NHTSA, Depart-
ment of ‘Transportation, Washington, D.C.

Rhea L. Dornbush, New York Medical College, Flower
and Fifth Avenue Hospital, New York, N.Y.

Douglas P. Ferraro, Department of Psychology, Univer-
sity of New Mexico, Albuquerque, New Mexico.

Stanley D. Glick, Herbert M. Singer Laboratory of
Neurosciences and Addictive Diseases, Beth Israel Medi-
cal Center, and Department of Pharmacology, Mt. Sinai
School of Medicine, New York, N.Y.

Peter Hall, Department of Physiology and Biophysics,
Colorado State University, Greeley, Colorado.

William H. Hark, Office of the Surgeon General,
Army, Washington, D.C.

Victor M. Holm, Bureau of Medicine and Sur
Department of the Navy, Washington, D.C.

D, E. McMillan, Department of Pharmacology, Scho
Medicine, University of North Carolina, Chapel
North Carolina.

Herbert Moskowitz, Departments of Engineering
Psychology, University of California, Los Angeles,
Department of Psychology, California State Unive:
Los Angeles, California.

Frank J. Sodetz, Department of Experimental Ps,
logy, Walter Reed Army Institute of Research, V
ington, D.C,

Appendix II
Relevant Bibliography

Abel, E. L.: Marihuana and Memory: Acquisition or
Retrieval?, SCIENCE, 173: 1038-1040, 1971.

Caldwell, D. F., 8. A. Myers, E. F. Domino, and P. E.
Marriman: Auditory and Visual Threshold Effects of
Marihuana in Man, PERCEPTUAL AND MOTOR
SKILLS, 29: 755-759, 1969.

Clark, L. D., and E. N. Nakashima : Experimental Studies
of Marihuana, AMERICAN JOURNAL OF PSYCHIA-
TRY, 125: 379-384, 1968.

Crancer, A., J. M. Dille, J. C. Delay, J. E. Wallace, and
M. D. Haykin: Comparison of the Effects of Marihuana
and Simulated Driving Performance, SCIENCE, 164:
851-854, 1969.

Dornbush, R. L., M. Fink, and A, M, Freedman: Mari-
huana, Memory and Perception, AMERICAN JOURNAL
OF PSYCHIATRY, 128: 194-197, 1971.

Jones, R, T.: Tetrahydrocannabinol and the Marih
Induced Social “High,” or the Effects of the Min
Marihuana, ANNALS OF THE NEW YORK ACAD
OF SCIENCES, 191: 155-165, 1971.

Kalant, H.: Marihuana and Simulated Dri
SCIENCE, 166: 640, 1969.

Manno, J. E., G. E. Kiplinger, N. Scholz, and R. Fo)
The Infiuence of Alcohol and Marijuana on Motor
Mental Performance, CLINICAL PHARMACOL
AND THERAPEUTICS, 12: 202-211, 1971.

Melges, F. T., J. R. Tinklenberg, and L. Hollister:

poral Disintegration and Depersonalization During

juana Intoxication, ARCHIVES OF GENERAL

CHIATY, 23: 204-210, 1970.

Tinklenberg, J. R., F. T. Melges, L. E. Hollister.
H. K. Gillespi Marihuana and Immediate Me
NATURE, 226: 1171-1172, 1970.





ACKNOWLEDGMENT

We gratefully acknowledge the assistance of Mrs. Dorothy Gay who
transcribed all of the Symposium discussion periods from tape recordings
to typed copy for use in compiling this report.