PTSD Symptom Reports of Patients Evaluated for the New Mexico Medical Cannabis Program

Abstract

New Mexico was the first state to list post-traumatic stress disorder (PTSD) as a condition for the use of medical cannabis. There are no published studies, other than case reports, of the effects of cannabis on PTSD symptoms. The purpose of the study was to report and statistically analyze psychometric data on PTSD symptoms collected during 80 psychiatric evaluations of patients applying to the New Mexico Medical Cannabis Program from 2009 to 2011.
The Clinician Administered Posttraumatic Scale for DSM-IV (CAPS) was administered retrospectively and symptom scores were then collected and compared in a retrospective chart review of the first 80 patients evaluated.
Greater than 75% reduction in CAPS symptom scores were reported when patients were using cannabis compared to when they were not.
Cannabis is associated with reductions in PTSD symptoms in some patients, and prospective, placebo-controlled study is needed to determine efficacy of cannabis and its constituents in treating PTSD.

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Journal of Psychoactive Drugs
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PTSD Symptom Reports of Patients Evaluated for the
New Mexico Medical Cannabis Program
George R. Greer M.D.a, Charles S. Grob M.D.b & Adam L. Halberstadt Ph.D.c
a Private practice, Santa Fe, NM
b Professor, Department of Psychiatry and Biobehavioral Sciences and Department of
Pediatrics, and Director, Division of Child and Adolescent Psychiatry, Harbor-UCLA Medical
Center, Torrance, CA
c Assistant Research Scientist, Department of Psychiatry, University of California San Diego,
La Jolla, CA
Published online: 11 Mar 2014.
To cite this article: George R. Greer M.D., Charles S. Grob M.D. & Adam L. Halberstadt Ph.D. (2014) PTSD Symptom Reports
of Patients Evaluated for the New Mexico Medical Cannabis Program, Journal of Psychoactive Drugs, 46:1, 73-77, DOI:
10.1080/02791072.2013.873843
To link to this article: http://dx.doi.org/10.1080/02791072.2013.873843
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Journal of Psychoactive Drugs, 46 (1), 73–77, 2014
Copyright © Taylor & Francis Group, LLC
ISSN: 0279-1072 print /2159-9777 online
DOI: 10.1080/02791072.2013.873843
PTSD Symptom Reports of Patients
Evaluated for the New Mexico Medical
Cannabis Program
George R. Greer, M.D.a; Charles S. Grob, M.D.b& Adam L. Halberstadt, Ph.D.c
Abstract —Background: New Mexico was the first state to list post-traumatic stress disorder (PTSD)
as a condition for the use of medical cannabis. There are no published studies, other than case reports,
of the effects of cannabis on PTSD symptoms. The purpose of the study was to report and statistically
analyze psychometric data on PTSD symptoms collected during 80 psychiatric evaluations of patients
applying to the New Mexico Medical Cannabis Program from 2009 to 2011. Methods: The Clinician
Administered Posttraumatic Scale for DSM-IV (CAPS) was administered retrospectively and symptom
scores were then collected and compared in a retrospective chart review of the first 80 patients evalu-
ated. Results: Greater than 75% reduction in CAPS symptom scores were reported when patients were
using cannabis compared to when they were not. Conclusions: Cannabis is associated with reductions
in PTSD symptoms in some patients, and prospective, placebo-controlled study is needed to determine
efficacy of cannabis and its constituents in treating PTSD.
Keywords — cannabis, post-traumatic, stress, tetrahydrocannabinol, THC, treatment
INTRODUCTION
In 2009, New Mexico became the first state to explic-
itly authorize the use of medical cannabis for people
with PTSD. Approved patients are allowed to purchase
cannabis from licensed, non-profit growers/producers or
to grow their own supply. The new regulation of cannabis
use for PTSD required evaluation by a psychiatrist certi-
fying: “(1) the aforementioned patient has a debilitating
medical condition and the potential health benefits of the
medical use of marijuana would likely outweigh health
risks for the patient. 2) the aforementioned patient has
aPrivate practice, Santa Fe, NM.
bProfessor, Department of Psychiatry and Biobehavioral Sciences
and Department of Pediatrics, and Director, Division of Child and
Adolescent Psychiatry, Harbor-UCLA Medical Center, Torrance, CA.
cAssistant Research Scientist, Department of Psychiatry, University
of California San Diego, La Jolla, CA.
Please address correspondence to George R. Greer, M.D., 2019
Galisteo, Bldg. N2, Santa Fe, NM 87505; phone and fax: +1 505 982
0312; email: george@newmexico.com
current unrelieved symptoms that have failed other medi-
cal therapies” (New Mexico Department of Health 2012).
Later, psychiatric nurse practitioners were authorized to
conduct the evaluations. As of the most recent report
available at this writing, there were 5,495 active medical
cannabis patients, of whom 1,854 (34%) had PTSD and
1,355 had chronic pain (New Mexico Department of Health
2011).
A literature search of “cannabis AND PTSD” through
PubMed yielded 42 references, some of which reported
a positive association of PTSD with cannabis use (Bonn-
Miller, Vujanovic & Drescher 2011;Cougle et al. 2011), or
abuse and dependence (Cornelius et al. 2010). One article
reviewed the anxiolytic properties of the cannabinoid,
cannabidiol (Schier et al. 2012), and one included a case
report and a thorough discussion on the use of cannabis
as a PTSD treatment and possible mechanisms of action
(Passie et al. 2012).
In one unpublished, open-label pilot study, smoked
medical cannabis containing 23% tetrahydrocannabinol
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Greer, Grob & Halberstadt PTSD Symptom Reduction with Medical Cannabis
(THC) and less than 1% cannabidiol was administered to
29 male Israeli combat veterans with PTSD, with instruc-
tions to smoke it daily (Mashiah 2012). The baseline
score on the Clinician Administered Posttraumatic Scale
for DSM-IV (CAPS) was 98 for the entire group, and post-
treatment scores in three subgroups after four to 11 months
of treatment ranged from 54 to 60.
Soon after the New Mexico PTSD regulation went into
effect, one of the authors [GG] began receiving unsolicited
phone calls in his private practice from people asking to
be evaluated as part of their application to the Program.
In order to avoid evaluating patients who would be unlikely
to qualify, telephone screening was conducted to deter-
mine whether they met the following criteria by self-report:
(1) the experience of and emotional response to a trauma
that met the DSM-IV Criterion A for PTSD; (2) the pres-
ence of several of the major symptoms in Criteria B, C,
and D (reexperiencing, avoidance, and hyperarousal) of
PTSD when not using cannabis; (3) significant relief of
several major PTSD symptoms when using cannabis; and
(4) lack of any harm or problems in functioning resulting
from cannabis use. All patients who met these screening
criteria were evaluated.
The CAPS was utilized during the evaluation to quan-
tify the patients’ symptoms retrospectively with and with-
out cannabis use. The CAPS is a frequently used instrument
in PTSD research that was developed by the National
Center for PTSD and two Veterans Affairs medical centers
(Blake et al. 1995). The instrument asks questions about the
presence of traumatic experiences and the immediate emo-
tional response to them described in DSM-IV Criterion A
for PTSD, and asks for a rating of the frequency and inten-
sity of all 17 symptoms in Criteria B, C, and D on a scale
of 0 to 4. On the CAPS scoring form, the frequency and
intensity scores are added to create a total score for that
symptom; then a total score for all the symptoms within
each criterion, and for all symptom criteria, are calculated.
During the evaluation, patients were asked to answer
the symptom questions for Criteria B, C, and D retrospec-
tively for a time period when they were not using cannabis,
and for a period when they were using it, and scores
were recorded for each period. No urine drug screens were
collected to verify recent cannabis use.
After conducting over 80 such evaluations between
mid-2009 and the end of 2011, all with adults over age
18, CAPS scores were analyzed to assess differences in
PTSD symptoms with vs without cannabis use. The null
hypothesis was that there would be no significant differ-
ence in CAPS scores between the cannabis and no-cannabis
conditions.
MATERIALS AND METHODS
Study procedures were approved by the Institutional
Review Board (IRB) of the Los Angeles BioMedical
Research Institute at Harbor-UCLA Medical Center.
Retrospective chart review procedures were conducted for
the first 80 patients evaluated by GG for participation in
the New Mexico Department of Health’s Medical Cannabis
Program for PTSD. The data collection procedure began
with GG scanning each of the CAPS scoring forms for
Criteria B, C, and D to a file in .pdf format. The .pdf files
and spreadsheet were then sent to the two other investiga-
tors, CG and AH. Per IRB rules, no identifying information
was extracted from patient records, or seen or retained by
any of the investigators.
CAPS symptom cluster (re-experiencing, avoidance,
and arousal) scores were analyzed using two-way analy-
sis of variance (ANOVA) with time period (no-cannabis
vs. cannabis) as a within-subject factor. When the two-way
ANOVA detected significant main effects of time period
or interactions between time period and symptom cluster,
post-hoc pairwise comparisons were performed by one-
way ANOVA. CAPS scores in patients using cannabis were
also analyzed as %baseline (no-cannabis) scores using
two-tailed one-sample t-tests. Statistical significance was
demonstrated by surpassing an αlevel of .01.
In addition to statistically analyzing the Criteria B,
C, and D symptom scores, the initial plan was to record
whether the patient met diagnostic criteria for PTSD with
and without cannabis use. However, no single scoring rule
or method of the nine suggested by the CAPS Manual
(Weathers, Ruscio & Keane 1999) was appropriate for this
study. Determining whether someone has or does not have
a PTSD diagnosis based solely on any of the nine CAPS
scoring methods would exaggerate the perception of a dif-
ference that did not reflect the clinical condition of the
person, because the frequency and intensity of all the symp-
toms exist on a continuum. Therefore, a patient who barely
qualified for the diagnosis according to one of the scoring
rules/methods would not be very different from someone
who almost qualified.
RESULTS
CAPS scores for the no-cannabis and cannabis con-
ditions are shown in Figure 1. Within-subject analysis
showed that there was a significant reduction of total CAPS
scores (F(1,79) =1119.55, p<0.0001) when patients
were using cannabis (22.5 ±16.9 (mean ±S.D.)) com-
pared with the no-cannabis condition (98.8 ±17.6). There
were also significant reductions in CAPS symptom clus-
ter scores (Cannabis ×Cluster: F(2,158) =39.87, p<
0.0001) in patients using cannabis. Post-hoc analysis con-
firmed that scores were reduced during cannabis use for
Criterion B (core symptom cluster of re-experiencing),
which decreased from 29.5 ±6.4 to 7.3 ±5.9 (F(1,79) =
734.98, p<0.0001); Criterion C (numbing and avoidance),
which decreased from 38.2 ±8.4 to 8.7 ±8.0 (F(1,79) =
783.73, p<0.0001); and Criterion D (hyperarousal), which
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Greer, Grob & Halberstadt PTSD Symptom Reduction with Medical Cannabis
FIGURE 1
CAPS Scores for the No-Cannabis and Cannabis Conditions. Data Are Expressed as Group Means ±S.D.
∗Significant Difference Between CAPS Scores, p<0.0001.
decreased from 31.0 ±6.2 to 6.6 ±6.0 (F(1,79) =910.79,
p<0.0001).
CAPS scores in patients using cannabis were also
analyzed as %baseline (no-cannabis) scores. Use of
cannabis was associated with a reduction of total CAPS
scores to 22.7 ±15.9% of baseline (t(79) =-43.48, p<
0.0001); similar reductions occurred in Criterion B (24.8
±18.9%; t(79) =-35.59, p<0.0001), Criterion C (22.5
±19.5%; t(79) =-35.59, p<0.0001), and Criterion D
(21.0 ±17.6%; t(79) =-40.12, p<0.0001) scores.
One finding was that only 19 of the 80 patients
reported any score at all for Criterion C3 (inability to recall
an important aspect of the trauma) with no cannabis, and
the mean score for C3 was much smaller than the mean
scores for the other 16 criteria (main effect of criteria
for the no cannabis condition: F(16,1264) =43.18, p<
0.0001). As shown in Table 1, post-hoc analysis confirmed
that the Criterion C3 values for the no-cannabis time period
were significantly different than the values for all other
criteria during the same time period.
DISCUSSION
Patients in this sample reported over 75% reduction in
all three areas of PTSD symptoms while using cannabis.
Because this was a highly select group of pre-screened
patients who had already found that cannabis reduced their
PTSD symptoms and who sought entry to the NM Medical
Cannabis Program to avoid criminal penalties for cannabis
TABLE 1
DSM IV Criteria B, C, and D Scores During the
No-Cannabis Time Period
Criteria Mean S.D. N Comparison Versus C3
B1 6.7 1.2 80 F(1,79) =362.53, p<0.0001
B2 5.7 2.5 80 F(1,79) =123.80, p<0.0001
B3 4.1 2.9 80 F(1,79) =48.62, p<0.0001
B4 6.5 1.5 80 F(1,79) =273.24, p<0.0001
B5 6.5 1.4 80 F(1,79) =279.16, p<0.0001
C1 6.7 1.7 80 F(1,79) =266.72, p<0.0001
C2 6.5 1.6 80 F(1,79) =308.42, p<0.0001
C3 1.2 2.4 80
C4 6.2 2.1 80 F(1,79) =211.79, p<0.0001
C5 6.2 2.0 80 F(1,79) =229.73, p<0.0001
C6 5.9 2.3 80 F(1,79) =185.00, p<0.0001
C7 5.6 2.8 80 F(1,79) =118.92, p<0.0001
D1 7.1 1.7 80 F(1,79) =339.92, p<0.0001
D2 5.9 2.2 80 F(1,79) =153.62, p<0.0001
D3 5.9 1.7 80 F(1,79) =214.04, p<0.0001
D4 6.3 2.1 80 F(1,79) =221.47, p<0.0001
D5 5.8 2.0 80 F(1,79) =178.75, p<0.0001
possession, reports of significant symptom reduction could
be expected. Some degree of intentional or unintentional
exaggeration of symptom differences on the part of the
patients is likely, and some unintentional bias on the
part of the psychiatrist conducting the evaluations is also
possible.
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Greer, Grob & Halberstadt PTSD Symptom Reduction with Medical Cannabis
Another factor is that some patients may have
reported their no-cannabis PTSD symptoms when they
were also experiencing a cannabis-withdrawal syndrome.
Nightmares, anger, and insomnia have been reported as
common symptoms of cannabis withdrawal (Allsop et al.
2011). Those three symptoms are among the 17 symptoms
of PTSD, and so could have resulted in higher no-cannabis
CAPS scores for those symptoms. However, in this retro-
spective chart review, no information was collected on the
length of the time periods without cannabis use. Therefore,
there is no valid way to quantify the degree to which
cannabis-withdrawal symptoms may have increased the
CAPS scores for those three PTSD symptoms. However,
even with the above confounding variables, the amount of
reported symptom relief is noteworthy.
Furthermore, the variability in scores with cannabis
use was relatively high, with the standard deviation being
almost equal to the mean total scores and the scores of
the three symptom clusters. If patients had consistently
reported frequent and severe symptoms without cannabis
and almost no symptoms with cannabis in order to make
sure they qualified for the Program, one would expect
less variability in the cannabis scores. Finally, the rela-
tively consistent reporting of low or “0” scores on Criterion
C3 without cannabis (see Table 1) is another indication that
most patients were not malingering by exaggerating their
no-cannabis scores for every single symptom in order to
qualify for the program. In fact, their reporting low scores
for this symptom is consistent with psychometric litera-
ture on the CAPS: “Finally, with the exception of amnesia,
the prevalence of each of the 17 core PTSD symptoms
on the CAPS was significantly greater in participants with
PTSD than in those without PTSD, indicating robust dis-
crimination between the two groups” (Weathers, Keane &
Davidson, 2001).
Because only patients who reported benefit from
cannabis in reducing their PTSD were studied, no con-
clusions can be drawn as to what proportion or type of
PTSD patients would benefit from treatment with cannabis
or its constituents. The reported anxiolytic properties of
cannabidiol may partly explain the reported benefit, though
the cannabis in the Israeli study reportedly contained
almost no cannabidiol (Mashiah 2012). That small, open-
label prospective study comes closer to showing a benefit,
at least for people with combat-related PTSD. It has also
been reported that the synthetic cannabinoid nabilone can
reduce the incidence and severity of nightmares in PTSD
patients (Fraser 2009).
The finding that use of cannabis can reduce symptoms
of PTSD is consistent with preclinical evidence showing
that the endocannabinoid system is involved in the regula-
tion of emotional memory. There is extensive evidence that
cannabinoids may facilitate extinction of aversive mem-
ories (de Bitencourt, Pamplona & Takahashi 2013). For
example, in rodents, the full CB1 receptor agonist WIN
55,212-2 (Pamplona et al. 2006;Pamplona, Bitencourt
& Takahashi 2008) and the fatty acid amide hydrolase
inhibitor AM404 (Pamplona et al. 2006;Chhatwal et al.
2005) facilitate extinction of conditioned fear. Given the
role that the endocannabinoid system plays in fear extinc-
tion, it is possible that the marked reduction in PTSD
symptomatology reported with cannabis use in the present
study was due to facilitated extinction of fear memories.
Additional studies are necessary to identify the specific
mechanism by which cannabis use attenuates the symptoms
of PTSD.
CONCLUSION
Though currently there is no substantial proof of the
efficacy of cannabis in PTSD treatment, the data reviewed
here supports a conclusion that cannabis is associated with
PTSD symptom reduction in some patients, and that a
prospective, placebo-controlled study of cannabis or its
constituents for treatment of PTSD is warranted.
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