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Cannabinoids 2008;3(1):1-3
© International Association for Cannabis as Medicine 1
Case report
Cannabis improves symptoms of ADHD
Peter Strohbeck-Kuehner, Gisela Skopp, Rainer Mattern
Institute of Legal- and Traffic Medicine, Heidelberg University Medical Centre, Voss Str. 2, D-69115 Heidelberg, Germany
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is characterized by attention deficits and an al-
tered activation level. The purpose of this case investigation was to highlight that people with
ADHD can benefit in some cases from the consumption of THC. A 28-year old male, who showed
improper behaviour and appeared to be very maladjusted and inattentive while sober, appeared to
be completely inconspicuous while having a very high blood plasma level of delta-9-
tetrahydrocannabinol (THC). Performance tests, which were conducted with the test batteries
ART2020 and TAP provided sufficient and partly over-averaged results in driving related per-
formance. Thus, it has to be considered, that in the case of ADHD, THC can have atypical effects
and can even lead to an enhanced driving related performance.
Keywords: ADHD, cannabis, performance, driving
This article can be downloaded, printed and distributed freely for any non-commercial purposes, provided the original work is prop-
erly cited (see copyright info below). Available online at www.cannabis-med.org
Author's address: Peter Strohbeck-Kuehner, peter.strohbeck@med.uni-heidelberg.de
Introduction
Assessing the performance or impairment of cannabis
users is generally problematic as there is no stringent
proof of a linear dose-effect relationship between the
concentration of delta-9-tetrahydrocannabinol (THC)
in blood and THC-induced impairment. The cause of
the absence of such a relationship has not been identi-
fied. In this context it is rarely considered that the miss-
ing correlation may be due in part to a conceivable
positive effect of cannabis on the behaviour and per-
formance of individuals. Recently, Adriani et al. [1]
gave evidence that cannabinoid agonists reduce hyper-
activity in a spontaneously hypertensive rat strain,
which is regarded as a validated animal model for at-
tention deficiency hyperactivity disorder (ADHD).
There was also a significantly better treatment retention
of cocaine dependent patients with comorbid ADHD
among moderate users of cannabis compared to ab-
stainers or heavy users [2].
ADHD was long considered a disorder limited to chil-
dren and adolescents. It has now been proven that
ADHD symptoms may persist into adulthood [3,4].
Individuals suffering from ADHD characteristically
have an increased drive to move around and are unable
to calm down. They are lacking in directed planning of
their actions and the ability to assess the impact of their
decisions. Their ability to organize day-to-day activi-
ties is reduced, they usually have a poor short-term
memory, are forgetful and tend to work in a chaotic
and inefficient way. Emotionally, they are prone to
impulsive outburst, excessiveness and instability [5,6].
This present case study describes a male, 28 years of
age, who was diagnosed with attention deficit hyperac-
tivity disorder (ADHD), and whose response to THC
suggests that such a positive effect may exist. Consid-
ering that the subject applied for the reinstallation of
his driving licence gives particular significance to psy-
cho-physical performance deficits caused by ADHD.
Numerous studies have shown that various perform-
ance functions, such as divided attention, selective
attention, long-term attention and vigilance are im-
paired [7].
Case Description
The subject had a record of several violations of the
German drug control law. He also had a record of nu-
merous violations of traffic laws, including speeding,
running of a red traffic light and driving under the
influence of cannabis during which a high THC con-
centration in blood had been detected.
Seven years ago, the subject had been diagnosed with
ADHD (ICD 10 F90.0) for the first time, and that diag-
nosis had been assessed repeatedly and independently
since by several psychiatric units. There was some
Case report
2 Cannabinoids Vol 3, No 1 March 2, 2008
evidence from his carrier that typical symptoms were
already present in childhood, they were, however, not
properly recorded. Comorbidities such as addiction,
including cannabis, or personality disorders were ab-
sent. He had been treated over a period of about 12
months through a combination of methylphenidate
(Ritalin®, 20-30 milligram/day) and behaviour ther-
apy. Being not sufficiently efficacious, the medication
was stopped. A subsequent certificate by a specialist
for general medicine suggests that ADHD symptoms
were much improved under cannabis and that dronabi-
nol (THC) had been prescribed, even though ADHD is
not indicated for this drug.
Prior to the first contact the subject had been advised
not to consume any medicinal or recreational drug.
During that first visit he showed grossly conspicuous
behaviour. His attitude was pushy, demanding and
lacking distance. He expressed impatience, for example
by drumming his fingers on the table. He also con-
stantly shifted position, folded arms behind his head or
leaned over the table in front of him. He was not open
to discussing the potential impairment of driving skills
caused by cannabis consumption. As the conversation
continued and he was informed of the preconditions for
a positive assessment of his suitability to operate a
vehicle, his behaviour became even more conspicuous
and aggressive. Finally, he got up, grabbed the table,
leaned forward and shouted that he needed a driving
license and that he needed cannabis. Overall he showed
behaviour typical of persons who suffer from ADHD.
During this visit, an appropriate performance of the
tests was impossible.
He was then offered to undergo, at a later time, a test of
the impact of dronabinol on performance. During this
appointment he appeared fundamentally changed and
was not disturbed at all. He stated that he had stopped
smoking cannabis, was taking dronabinol on a regular
basis and that he had consumed it just two hours ago.
He appeared calm, but not sedated, organized and re-
strained. Unlike during the first meeting he was able to
accept and discuss arguments. When trying to make
clear that THC was indispensable for his quality of life
he became more engaged but without losing restraint.
Rather, he was understanding of the position of the
expert and indicated that the path to get back his driver
license may be long but that he was willing to under-
take it. His behaviour, motor function, mood and con-
sciousness did not give any indications of a prior use of
a psychoactive substance.
The tests of performance functions that are relevant to
driving skills involved the four subtests of ART2020, a
computer-controlled test system, which is commonly
used to assess driving performance. These subtests
evaluate complex reactions (RST3), sustained attention
(Q1), directed attention (LL3) and visual surveying and
perception (TT15). In addition the functions of “vigi-
lance” and “divided attention” were tested with the
attention test module (TAP).
The results of these tests (see Fig. 1) showed that the
subject met, in all of the functions tested by ART2020,
not only minimum criteria but that he achieved average
or, in some areas, even above-average results. In the
very demanding tests for “vigilance” and “divided
attention” categories he also showed average perfor-
mance. ADHD or acute effects of THC by themselves
would usually impair performance particularly in these
tests.
A blood sample was taken after completion of the tests.
It showed a very high concentration of THC (71 ng/mL
serum), of the psychoactive metabolite 11-hydroxy-
0
10
20
30
40
50
60
70
80
90
100
RST3 Q1 LL5 TT15 Vigil. Div. Att.
Performance
Criteria
Figure 1: Subjects actual performance and minimum criteria.
Strohbeck-Kuehner
Cannabinoids Vol 3, No 1 March 2, 2008 3
THC (30 ng/mL serum) and of the main non-
psychoactive metabolite 11-nor-delta-9-carboxy-THC
(251 ng/mL serum). Such levels indicate recent as well
as frequent consumption of THC-containing matters,
and the analyte pattern also suggests smoking. Detec-
tion of cannabinol in hair (5.3 ng/mg) along with THC
(3 ng/mg) gives evidence that the medication could not
have been the only source of the THC.
Only much later did the subject, who had been arrested
for a drug offence a few days after the second visit,
report that he had not consumed pharmaceutical dron-
abinol products but instead smoked cannabis just be-
fore the tests, since it was much less costly.
Conclusions
The present case report suggests that individuals suffer-
ing from ADHD, a dysfunction with a symptomatic
change in activity levels, may - in some cases - benefit
from cannabis treatment in that it appears to regulate
activation to a level which may be considered optimum
for performance. There was evidence, that the con-
sumption of cannabis had a positive impact on per-
formance, behaviour and mental state of the subject.
The present observation corroborates previous data of
Müller-Vahl et al. [8] suggesting that in patients suffer-
ing from Tourette syndrome, treatment with THC
causes no cognitive defects. Gilles de la Tourette syn-
drome is a neurobehavioral disorder associated with
motor and vocal tics as well as behavioural and cogni-
tive problems. The authors also hypothesized that the
effects of cannabinoids in patients may be different
from those in healthy users suggesting an involvement
of the central cannabinoid receptor systems in the pa-
thology of the disorder. The same conclusion may be
drawn from previous studies [1, 2] and the present case
report, although more information on these atypical
effects should be provided and the underlying mecha-
nisms are still to be elucidated.
References
1. Adriani W, Caprioli A, Granstrem O, Carli M,
Laviola G. The spontaneously hypertensive- rat
as an animal model of ADHD: evidence for im-
pulsive and non-impulsive subpopulations. Neu-
rosci Biobehav Rev 2003;27:639-651.
2. Aharonovich E, Garawi F, Bisaga A, Brooks D,
Raby, WN, Rubin, E, Nunes EV, Levin FR. Con-
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bid ADHD and cocaine dependence: effects on
outcome. Am J Drug Alcohol Abuse 2006;32:
629-635.
3. Mannuzza S, Klein RG, Bessler A, Malloy P,
Lapadula M. Adult outcome of hyperactive boys.
Arch Gen Psychiatry 1992;50:565-576.
4. Murphy K, Barkley RA. Attention deficit hyper-
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7. Woods SW, Lovejoy DW, Ball JD. Neuropsy-
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Emrich HM. Treatment of the Tourette syndrome
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The complete case-report was published in 2007 in
Archiv fuer Kriminologie 220: 11-19.
