Cannabidiol for the treatment of psychosis in Parkinsons disease

Abstract

The management of psychosis in Parkinson's disease (PD) has been considered a great challenge for clinicians and there is a need for new pharmacological intervention. Previously an antipsychotic and neuroprotective effect of Cannabidiol (CBD) has been suggested. Therefore, the aim of the present study was to directly evaluate for the first time, the efficacy, tolerability and safety of CBD on PD patients with psychotic symptoms. This was an open-label pilot study. Six consecutive outpatients (four men and two women) with the diagnosis of PD and who had psychosis for at least 3 months were selected for the study. All patients received CBD in flexible dose (started with an oral dose of 150 mg/day) for 4 weeks, in addition to their usual therapy. The psychotic symptoms evaluated by the Brief Psychiatric Rating Scale and the Parkinson Psychosis Questionnaire showed a significant decrease under CBD treatment. CBD did not worsen the motor function and decreased the total scores of the Unified Parkinson's Disease Rating Scale. No adverse effect was observed during the treatment. These preliminary data suggest that CBD may be effective, safe and well tolerated for the treatment of the psychosis in PD.

Full text

Cannabidiol for the treatment of
psychosis in Parkinson’s disease
AW Zuardi Department of Neuropsychiatry and Medical Psychology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.
JAS Crippa Department of Neuropsychiatry and Medical Psychology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.
JEC Hallak Department of Neuropsychiatry and Medical Psychology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.
JP Pinto Department of Neuropsychiatry and Medical Psychology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.
MHN Chagas Department of Neuropsychiatry and Medical Psychology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.
GGR Rodrigues Department of Neuropsychiatry and Medical Psychology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.
SM Dursun Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada.
V Tumas Department of Neuropsychiatry and Medical Psychology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.
Abstract
The management of psychosis in Parkinson’s disease (PD) has been
considered a great challenge for clinicians and there is a need for new
pharmacological intervention. Previously an antipsychotic and
neuroprotective effect of Cannabidiol (CBD) has been suggested.
Therefore, the aim of the present study was to directly evaluate for the
first time, the efficacy, tolerability and safety of CBD on PD patients with
psychotic symptoms. This was an open-label pilot study. Six consecutive
outpatients (four men and two women) with the diagnosis of PD and who
had psychosis for at least 3 months were selected for the study. All
patients received CBD in flexible dose (started with an oral dose of
150 mg/day) for 4 weeks, in addition to their usual therapy. The psychotic
symptoms evaluated by the Brief Psychiatric Rating Scale and the
Parkinson Psychosis Questionnaire showed a significant decrease under
CBD treatment. CBD did not worsen the motor function and decreased the
total scores of the Unified Parkinson’s Disease Rating Scale. No adverse
effect was observed during the treatment. These preliminary data suggest
that CBD may be effective, safe and well tolerated for the treatment of the
psychosis in PD.
Key words
cannabidiol; CBD; Parkinson’s disease; psychosis; treatment
Introduction
Psychosis is common in Parkinson’s disease (PD), affecting
nearly one-third of patients particularly in later stages of the
disease (Naimark, et al., 1996). The pathophysiology of psy-
chosis in PD remains unknown and seems to be multifactorial
(Ravina, et al., 2007). Levodopa and other antiparkinsonian
medications have been incriminated as the main cause, and
the psychosis is frequently referred as drug induced. However,
it was recognised as an integral part of the disease process even
before the introduction of L-dopa (Thanvi, et al., 2005). Fur-
thermore, it is interesting to note that hallucinations appear
to be correlated with the severity of cognitive decrease indepen-
dent of the dopamine precursor treatment (Fenelon, et al.,
2000). It has been hotly debated that dopamine and its func-
tional interactions with other neurotransmitters may play an
important role (Birkmayer and Riedere, 1975). There is also
evidence of the involvement of Lewy Body pathology in the
ventral temporal regions of the brain in PD psychosis (Wil-
liams and Lees, 2005).
The management of psychosis in PD remains problematic
and has been considered a great challenge for clinicians.
Reduction in drug dosage or elimination of one or more anti-
parkinsonian agents is recommended as the first line therapy,
but it is not always possible to apply it effectively. Otherwise,
an add-on therapy with most conventional antipsychotics can
produce unacceptable side-effects with further worsening of the
motor symptoms and thus must be avoided. The atypical anti-
psychotic, clozapine, is considered to be the most effective drug
in the treatment of psychosis in PD, with no worsening of
Short report
Journal of Psychopharmacology
00(00) (2008) 1–5
©2008 British Association
for Psychopharmacology
ISSN 0269-8811
SAGE Publications Ltd,
Los Angeles, London,
New Delhi and Singapore
10.1177/0269881108096519
Corresponding author: Antonio Waldo Zuardi, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil. Email: awzuardi@fmrp.usp.br
J Psychopharmacol OnlineFirst, published on November 21, 2008 as doi:10.1177/0269881108096519
Texto

motor symptoms, but requires mandatory monitoring of hae-
matology. Furthermore, clozapine can cause unacceptable car-
diovascular and neurological side-effects (Thanvi, et al., 2005).
Therefore, there is a need for a safe and effective pharmacolog-
ical intervention for PD psychosis.
Studies in animal models and in healthy volunteers clearly
suggest an anxiolytic and antipsychotic-like effects of cannabi-
diol (CBD), a Cannabis sativa (cannabis) component, which is
devoid of the typical psychological effects of cannabis in
humans Zuardi, et al., 2006a. Open case studies of patients
with schizophrenia treated with CBD (Zuardi, et al., 1995,
2006b) and a preliminary report of a controlled clinical trial
comparing CBD with amisulpride (Leweke, et al., 2007) have
suggested that CBD may be a safe and effective alternative
possibility to be developed as an antipsychotic drug.
CBD’s neuroprotective effects have recently been reported
in animal models of PD (Lastres-Becker, et al., 2005; Garcia-
Arencibia, et al., 2007). These results suggest that CBD has
antioxidant properties providing neuroprotection against the
progressive degeneration of nigrostriatal dopaminergic neurons
occurring in PD.
Considering the relevance of these preclinical data and the
antipsychotic effect of CBD, the aim of the present study was
to directly evaluate for the first time the efficacy, tolerability
and safety of CBD on PD patients with psychotic symptoms,
in an open-label pilot study with flexible dose.
Methods
Study population
The study was conducted at the movement disorder outpatient
clinic of the University Hospital of the Faculty of Medicine of
Ribeirao Preto, Brazil. A diagnosis of PD was taken according
to the United Kingdom Parkinson’s Disease Society Brain
Bank criteria (Gibb and Lees, 1988). Patients were eligible if
they had psychosis for at least 3 months immediately before
entry into the study that could not be controlled with reduction
of antiparkinsonian medications and that were in stable doses
of anti-PD medication for at least 7 days. Exclusion criteria
included: diagnosis of a primary psychotic disorder, atypical
Parkinsonism, presence of dementia, motor symptoms that
would require increased anti-PD medication during the study
period or unstable medical and other neurological or psychiat-
ric condition.
Diagnostic psychiatric interviews were conducted by one of
the authors (JP), using the Portuguese version (Del-Ben, et al.,
2001) of the Structured Clinical Interview for DSM-IV (First,
et al., 1997). In the test–retest reliability study of this version,
in which both psychiatrists participated as evaluators, the con-
cordance (Kappa) was 0.90 for psychotic disorders in general.
Six consecutive outpatients (four men and two women),
mean age 58.8 ± 14.9 years, with a mean of 10.6 ± 3.7 years
of disease and a median of 1050 mg/day of L-dopa treatment
were included. No patient was on psychiatric medication.
Ethical considerations
All subjects and their responsible relatives (caregivers) gave
written informed consent after being fully informed of the
research procedure, following approval by the local ethical
committee.
Data collection
The subjects received CBD in addition to their usual therapy
for 4 weeks. CBD in powder, approximately 99.9% pure (sup-
plied by THC-Pharm, Frankfurt, Germany), was dissolved in
corn oil. The same amount of corn oil was used as a placebo.
The drug and placebo were packed inside identical gelatin cap-
sules. All subjects were started on one 150 mg CBD tablet and
the dose was increased weekly by 150 mg depending on the
clinical response. Capsules (in a light-resistant glass vial) were
dispensed on a weekly basis and the patients were asked to
return with the glass vial for the next drug supply. Family
members were also involved in the monitoring of adherence
to treatment. Subjects were evaluated before receiving CBD
and at the end of weeks 1, 2, 3 and 4 under the drug, at the
same time of the day and by same unblinded neurologist and
psychiatrist. Assessments included neurological and physical
examinations, vital signs and clinical assessments of adverse
events. The main outcome measure of efficacy and health was
the Bech’s version of the Brief Psychiatric Rating Scale (BPRS;
Bech, et al., 1986) translated and adapted to Portuguese
(Zuardi, et al., 1994) with the interviews performed using a
Structured Interview Guide (SIG), which has been shown to
enhance test–retest reliability of the BPRS (Crippa, et al.,
2001) and the Parkinson Psychosis Questionnaire (PPQ, Brand-
staedter, et al., 2005). The secondary outcomes were the Uni-
fied Parkinson’s Disease Rating Scale (UPDRS, Fahn, et al.,
1987), the Clinical Global Impression –Improvement scale
(CGI–I, National Institute of Mental Health, 1976), the Mini-
Mental Status Examination (MMSE, Folstein, et al., 1975) and
the Frontal Assessment Battery (FAB, Dubois, et al., 2000).
Comparisons of the rating scale scores were made by using the
non-parametric Friedman test and the Wilcoxon Signed Rank
test. All tests were two-tailed, and a probability of P≤0.05 was
taken as significant.
Results
Table 1 shows the median [minimum–maximum] scores of the
rating scales before and during the 4 weeks under CBD added
to patients’treatments.
Significant improvement with CBD in the total scores of
BPRS as well as in the four BPRS factors’scores, including
the ones specifically related to positive (thinking disorder) and
negative (withdrawal-retardation) symptoms (Crippa, et al.,
2002) were observed. Moreover, a questionnaire developed to
assess psychotic symptoms in PD, which quantifies the fre-
quency and severity of sleep disturbances, hallucinations/illu-
2Cannabidiol and psychosis in Parkinson’s disease

sions, delusions and orientation (PPQ), has also shown a signif-
icantly decrease in the scores after CBD treatment.
The total score of the UPDRS has decreased and the CGI-I
score improved significantly in the end point. The MMSE and
FAB scores did not significantly change during the trial.
Discussion
These results are in accordance with the previously suggested
potential antipsychotic effects of CBD (Zuardi, et al., 2006a).
The observed rapid onset of the antipsychotic effect in the
PD patients may be attributed to changes in dopaminergic neu-
rotransmission. Because the psychotic symptoms of these
patients were possibly associated with the use of the dopami-
nergic drugs, the observed antipsychotic effect of CBD may
have occurred through the attenuation of dopaminergic activity
in areas related to the production of psychotic symptoms. This
is consistent with the preclinical evidence that CBD has previ-
ously been shown to attenuate the stereotyped behaviour and
the hyperlocomotion induced by dopaminergic drugs in animal
models of psychosis (Zuardi, et al., 1991; Moreira, et al., 2005).
Indeed, the cannabinoid system seems to be involved with
the dopaminergic modulation because the stimulation of
Table 1 Rating scale scores (median [minimum–maximum]) at the different assessment times
Weeks (mean of cannabidiol dose –mg) Statistics
0(0) 1(150) 2(250) 3(325) 4(400)
BPRS
Total score 18.5 (11–26) 10.0 (2–18) 8.0 (0–16) 6.0 (0–12) 5.5 (0–12) χ
2
= 21.6
a
P<0.001
Thinking disorder 7.0 (3–10) 2.5 (0–7) 2.0 (0–5) 1.0 (0–3) 1.0 (0–2) χ
2
= 17.1
a
P=0.002
Withdrawal-retardation 5.0 (4–8) 3.5 (2–8) 3.0 (0–8) 3.0 (0–7) 3.5 (0–7) χ
2
= 14.1
a
P=0.007
Anxious-depression 3.0 (2–8) 1.0 (0–4) 1.5 (0–5) 0.5 (0–5) 1.0 (0–2) χ
2
= 15.9
a
P=0.003
Activation 2.5 (1–5) 1.0 (0–4) 0.0 (0–4) 0.0 (0–3) 0.0 (0–3) χ
2
= 14.9
a
P=0.005
PPQ
Total score 13 (4–21) 4 (2–8) 4.5 (0–11) 2.5 (0–9) 1.5 (0–4) χ
2
= 19.9
a
P=0.001
UPDRS
Mentation, behaviour and mood 6.25 (2–9) —— — 3.0 (0-9) Z=1.8
b
NS
Activities of daily living 17.0 (9–45) —— — 12.5 (3-45) Z=1.6
b
NS
Motor score 44.5 (20.5–62) —— — 36 (31–64) Z=1.2
b
NS
Complications of therapy 3 (1–7) —— — 2.5 (0–7) Z=0.4
b
NS
Total score 67.5 (38.5–123) —— — 51.5 (35–125) Z=2.0
b
P=0.046
MMSE
Total score 21 (16–26) —— — 25.5 (14–27) Z=1.6
b
NS
FAB
Total score 5.5 (3–13) —— — 7.0 (4–10) Z=0.3
b
NS
CGI-I
Very much improved = 1 4 2 (1–3) 2 (1–3) 1.5 (1–3) 1.5 (1–3) χ
2
= 17.9
a
P=0.001
No change = 4
Very much worse = 7
BPRS, brief psychiatric rating scale; PPQ, Parkinson psychosis questionnaire; UPDRS, unified Parkinson’s disease rating; CGI-I, clinical global impression
improvement; MMSE, mini-mental status examination; FAB, frontal assessment battery; NS, non significant.
a
Friedman test.
b
Wilcoxon signed rank test.
Cannabidiol and psychosis in Parkinson’s disease 3

cannabinoid CB1 receptors produces an activation of dopami-
nergic transmission (French, et al., 1997; Diana, et al., 1998).
Although CBD has shown low affinity with CB1 receptors
(Felder, et al., 1995), it seems to antagonise the CB1 agonists
(Thomas, et al., 2007) and the new described cannabinoid
receptor GPR55 (Ryberg, et al., 2007).
An important observation of this study was that CBD did
not worsen the motor function. Rather, the scores of all
UPDRS items decreased, but not reaching statistical signifi-
cance, including the item ‘motor examination’, although the
total score of this scale has decreased significantly. In animal
model of PD, daily administration of CBD during two weeks
produced a significant waning in the magnitude of toxic effects
produced by a unilateral injection of 6-hydroxydopamine into
the medial forebrain bundle (Lastres-Becker, et al., 2005),
probably by antioxidant cannabinoid receptor-independent
properties (Garcia-Arencibia, et al., 2007). This antioxidant
action of CBD is reinforced by the observation that this canna-
binoid reduced the striatal atrophy caused 3-nitropropionic
acid in an animal model of Huntington’s disease by mechan-
isms independent of the activation of cannabinoid, vanilloid
TRPV1 and adenosine A2A receptors (Sagredo, et al., 2007).
The neuroprotective effect of CBD in the human basal ganglia
was suggested by the strong positive correlation of N-
acetylaspartate/total creatine ratio and CBD in the putamen/
globus pallidum of recreational cannabis users. This could
reflect an enhancement of neuronal and axonal integrity in
these regions by CBD (Hermann, et al., 2007).
Another important finding was that CBD did not induce
any decrease in cognitive function because the MMSE and
FAB scores did not significantly change during the trial. No
adverse effect was observed during treatment with CBD.
The results of this pilot study showed that CBD may be
effective, safe and well tolerated for the treatment of the psy-
chosis in PD. However, randomised double-blind controlled
assays would be necessary to further confirm this observation.
Acknowledgements
This study was supported in part by grants from ‘Conselho Nacional de
Desenvolvimento Científico e Tecnológico’(CNPq-Brazil-554490/2005-6)
and from ‘Fundação de Amparo à Pesquisa do Estado de São Paulo fel-
lowship’(FAPESP - 02/13197-2). JAC and AWZ are recipients of a
CNPq Productivity (2006-2008) fellowship. This study was also sponsored
by THC-Pharm (Frankfurt, Germany) and STI-Pharm who kindly pro-
vided cannabidiol. Finally, we thank Ms Sandra Bernardo who helped on
data collection necessary for our study.
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