INDIAN JOURNAL OF PSYCHIATRY, 2003, 45 (III), 182-188
REVIEW ARTICLE
Psychiatric Morbidity of Cannabis Abuse
JAYDIP SARKAR, PRATIMA MURTHY, SWARAN P SINGH
ABSTRACT
The paper evaluates the hypothesis that cannabis abuse is associated with a broad
range of psychiatric disorders in India, an area with relatively high prevalence of
cannabis use. Retrospective case-note review of all cases with cannabis related
diagnosis over a 11 -year period, for subjects presenting to a tertiary psychiatric
hospital in southern India was carried out. Information pertaining to socio-
demographic, personal, social, substance-use related, psychiatric and treatment
histories, was gathered. Standardized diagnoses were made according to Diagnostic
Criteria for Research of the World Health Organization, on the basis of information
available.
Cannabis abuse is associated with widespread psychiatric morbidity that spans the
major categories of mental disorders under the ICD-10 system, although proportion
of patients with psychotic disorders far outweighed those with non-psychotic
disorders. Whilst paranoid psychoses were more prevalent, a significant number of
patients with affective psychoses, particularly mania, was also noted.
Besides being known as either the causative agent or a potent risk factor in cases
of paranoid psychoses, cannabis appears to have similar capabilities with regard to
affective psychoses, particularly in cases of mania. It is suggested that cannabis has
the potential to act as a "life event stressor" amongst subjects vulnerable to develop
affective psychoses and the possible aetiopathogenesis of such a finding is discussed.
Key words: Cannabis, psychiatric disorders
INTRODUCTION
Cannabis is one of the most frequently
abused psychoactive drugs (Grinspoon and
Bakalar 1993). Psychiatric disturbances
associated with cannabis use range from
minor psychological responses such as
anxiety and panic (Thomas 19%), to
depressive disorders (Troisi et al 1998), the
more serious mental illnesses such as the
putative 'cannabis psvehosis' (Talbott and
Teaguc 1969), acute functional psvehosis
(Johns 21KM), chronic psychosis (Ghodse
1986) and the poorly validated entity of
'*motivational svndrome (Hall ct al 1999).
The nature of association and the direction
of causality between cannabis use and
various mental disorders await elucidation
(Thomas 1993). The strongest evidence of
a specific contributory role of cannabis use
exists only in relation to schizophrenia
(Andreasen et al 1987).
India has a long tradition of cannabis
use, which is often socially sanctioned
(National Institute of Social Defense 1992).
The association between cannabis use and
mental disorders has been recorded for well
over a century (Indian Hemp Commission
Report 1894). Whilst considerable attention
has been paid to the association between
cannabis use and psychotic disorders (Basu
et al 1999, Thacore and Shukla 1976,
Chopra and Smith 1974), relatively little is
known about the impact of cannabis abuse
on wider psychiatric morbidity. We present
a retrospective study as preliminary
exploration to evaluate the hypothesis that
cannabis abuse will be associated with a
broad range of psychiatric disorders,
through a case-note review of patients
abusing cannabis who presented to a large
tertiary psychiatric hospital in south India.
We also explored the pattern of cannabis
use by this population.
METHODS
The Catchment Population: The study
was conducted at a tertiary referral center
in Bangalore, catering to a large catchment
area. All patients receive a diagnostic code
according to the criteria laid down in
successive revisions of the International
Classification of Diseases - ICD-9, (prior to
1992) and ICD-10 (thereafter). In keeping
with WHO recommendations, all comorbid
psychiatric diagnoses are coded for each
patient.
Sample: Selected case-notes with any
cannabis related diagnosis were identified
for the period between 1984-1994.
Data: Information was recorded for
socio-demographic data, history of substance
use and other clinical history variables.
Socio-demographic variables included
subject's age, sex, completed years of_.
education, and occupation. Substance use
variables were age of onset of cannabis use,
reason for initiation, duration of cannabis
use, duration of daily use, temporal sequence
of onset of psychiatric disorder in relation
to cannabis use, and use of any other
psychoactive substance prior to and following
the onset of cannabis use. Further, family
history of substance use and mental illness,
and the reason for establishing contact with
the hospital were recorded. Psychopathology
variables recorded included delusions
(reference, persecution, grandiosity, infidelity
and others), hallucinations in any modality,
thought disorder (including flight of ideas),
thought alienation phenomena, psychomotor
activity, mood disturbance, level of
sensorium, cognitive deficits and treatment
offered.
<
Information pertaining to
psychopathology was recorded in the
following manner:
a) for patients with 1 -2 contacts during the
study period, all phenomena displayed
(182)
CANNABIS AND PSYCHIATRIC MORBIDITY
during each of these contacts was
recorded. In doing so, the 'present
state' format for recording
psychopathology was adopted.
b) for patients with 3-5 contacts, symptoms
contained in the most recent contact
were recorded along with symptoms of
a similar type but with a more
characteristic symptom profile,
employing the notion of a 'representative
episode'. Where the most recent episode
of symptoms was different from the
representative episode (for example,
manic episode manifested upon a
depressive representative episode) both
sets of symptoms were recorded.
c) In cases with more than 5 contacts, all
varieties of symptoms e.g. psychotic,
affective and neurotic, as had been
displayed by the patient, were recorded.
Where there were two periods or
episodes with different types of
symptoms, these were rated as though
they were sub-episodes of one extended
episode employing the notion of
symptoms experienced in the 'lifetime
before'. This pattern is an acceptable
method of symptom recording in order
to generate diagnoses [World Health
Organization 1993a]. All diagnoses
were made on the basis of criteria laid
down in the Diagnostic Criteria for
Research, DCR, (World Health
Organization 1993 b).
RESULTS
Socio-demographic data
Two hundred and forty four notes were
identified as having a cannabis related
diagnosis. AU 244 subjects were male.
Their mean age was 30 years (S.D.  9.7;
Range = 18-82 years) and 53% were single
(109/204; data unrecorded = 40). They had
on average 9.7 years (S.D.  9.8) of education
and 45% had received between 5-10 years
of formal education. Sixty-two percent of
patients were employed with representation
of professional, skilled and unskilled workers
being 13%, 27% and 22% respectively.
Substance use history
The mean age of initiation of cannabis
use was 22.4 years (S.D. + 8.4 years; Range
= 10-65 years). Forty-three percent (9=105
had started using cannabis during the second
decades of their lives. Eighty-nine (36%)
began use during the third decade whilst
twenty-five (10%) did so in the fourth
decade. For the rest, onset of use was even
later. Where information pertaining to
reasons for cannabis use was recorded (n
= 115; 47%), 57% cited recreational and
experimental use, 12% attributed onset to
a dysphoric mood state while 11% cited
peer pressure as the primary reason.
Data was unavailable for total duration
of non-continuous (regular but not daily)
and continuous (daily) cannabis use in 32
(13%o) and 141 (58%) cases respectively.
The mean duration of non-continuous use
of cannabis was 80 months (S.D. +. 71
months) while the duration of continuous
use was 49 months (S.D.  50 months).
Amongst daily users, 32 (31%) subjects had
been using cannabis for less than 2 years,
44 (43 %) patients had been using it
between 2-5 years and 27 (26 %) patients
had consumed it for over 5 years.
Relation of cannabis use to
onset of psychiatric disorders
In 127 patients (52%), a psychiatric
disorder had occurred following cannabis
use while for 18 patients (7%), psychiatric
disturbance had preceded the onset of
cannabis use. Data were unavailable for 99
patients (41%). For 67% of patients cannabis
was the first drug of abuse in their substance
use life-trajectories. Alcohol and opioids
were the initial substance of abuse in 29%
and 4% patients respectively. Amongst
those using cannabis on a continuous basis,
15% also used polysubstance (cannabis,
alcohol and opioids for this study) while
11%) and 9% used only alcohol and opioids
respectively. Thus, 35% of cannabis users
also used other substances concurrendy,
whilst for the remaining 65% cannabis
remained the only substance of use. Data
on homotypic comorbidity (other comorbid
substance use disorders) was unavailable for
24 cases (see table 2).
TABLE I : Socio-demographic and substance use variables
Variable (N=244) Mean S.D. Range
Age of patient
Age of onset of cannabis use
Duration of
non-continuous cannabis use
Duration of
continuous cannabis use
30 years
22.4 years
80 months
49 months
+_9.7 years
+_ 8.4 years
+_ 71 months
+_ 50 months
18-82 years
10-65 years
1-244 months
1-240 months
TABLE 2 : Temporal relation between cannabis and other drug use
(n =244)
Opiates
Combination of the above
None
Not known
Substance
Following
n
64
8
2
146-
24
used
Cannabis
%
29'
4
1
66
Preceding
n
1
0
34
139
24
cannabis use
%
11
9
16
63
(183)
SARKAR at al
Family history
Data on family history were available in
202 (83%) subjects. 33 subjects (16%) had
a positive family history of a psychiatric
disorder and 48 (24%) had a positive family
history of substance abuse. Twenty-seven
percent of patients with non-psychotic
illnesses had a positive family history followed
by subjects with affective psychoses (26%),
paranoid psychoses including schizophrenia
(18%), cannabis psychosis (16%) and
substance misuse disorders (9%). Patients
with only substance misuse disorders had
the highest rate of family history of
substance misuse (32%), followed by subjects
with non-psychotic illness (29%), paranoid
Psychopathology
Delusional thinking was reported in 105
patients (43%). Persecutory delusions were
the commonest (26%) followed by grandiose
(22%) and referential (9%) delusions. Forty-
one percent of patients experienced
hallucinations, most commonly in the
auditory modality (25%). Thought disorder,
including 'flight of ideas', was recorded in
26 patients (11%). Elated mood (23%) was
more common than depressed mood (16%),
in patients with affective disturbances.
Thought alienation phenomena such as
thought broadcasting, thought insertion and
thought withdrawal were reported in 11
TABLE 3 : Family history of mental illness and substance misuse
Diagnostic groups Family History of Family History of Substance
Mental Illness Misuse
(data unavailable n=42, 17%) (data unavailable n=4l, 17%)
Non-psychotic
Affective psychosis
(DCR rubric of F30-39)
Non-affective psychosis
(DCR rubric of F20-29)
Cannabis psychosis
Substance misuse disorder
Total
n
4/15
8/31
7/39
8/51
6/65
33/202
%
27
26
18
16
9
16
n
4/14
4/30
9/41
9/50
22/68
48/203
%
29
13
22
18
32
24
psychoses (22%), cannabis psychosis (18%)
and affective psychosis (13%).
Reason for help seeking
For 110 patients (56%) (Data unavailable:
n= 47; 19%), display of abnormal behavior
usually noted by family members formed
the reason for establishing contact with the
clinical services. A third of the patients
contacted the hospital for relief from
distressing withdrawal symptoms of alcohol
and opioid withdrawal. Subjectively reported
depressed mood was the presenting
complaint in 11% patients.
(4%) cases. Increased psychomotor activity
(n=ll;4%), pressure of speech (n =9; 3%)
and a combination of the two (n=7; 2%)
were also evident in a small proportion of
patients.. Bizarre behaviour that included
such acts as smearing faeces, spitting,
inappropriate and vacuous laughter, living in
rubbish pits, taking off one's clothes, self
mutilation, mutism, and posturing was
reported in 31 (13%) cases. Catatonic
symptoms were included amongst these.
The case notes also recorded ten patients
as having clouding of consciousness (4%),
and seven patients (3%) with cognitive
deficits
Diagnosis
Two types of comorbidity were identified
in this cohort. Cannabis use disorder/s was
either associated with other substance use
disorder/s (but not with substance use
related mental disorder/s) or with
independent psychiatric disorder/s, i.e. non-
substance use related. The former was
referred to as homotypic while the latter as
heterotypic comorbidity [Degenhardt et al
2001].
a) Substance abuse comorbidity
(Homotypic comorbidity):
There were in all eight different types of
substance related diagnoses, other than
cannabis-related diagnoses, in the total cohort
(see table 4). There were 144 cases of
cannabis dependence, 95 cases of harmful
use (abuse) and five cases of acute
intoxication. One hundred nine patients
(47%) also received another substance misuse
disorder diagnosis, which included forty-
nine cases of alcohol abuse (n=23) or
dependence (n=26), thirty-six cases of
polysubstance abuse (n=13) or dependence
(n=23) and thirteen cases of opioid
dependence. Polysubstance abuse/
dependence was recorded in those abusing
three different substances concurrendy:
cannabis, alcohol and opioids. There were
no case of amphetamine, benzodiazepine,
cocaine, ecstasy, LSD, inhalant or steroid
abuse. The prevalence of nicotine and
caffeine use was not recorded. Substance
misuse/dependence was the only psychiatric
diagnosis in eighty cases (34%). This
number may appear to be smaller than what
the preceding figures suggest as patient with
more than one substance abuse/dependence
were counted more than once under the
respective headings. For instance a patient
with cannabis abuse/dependence who was
Comorbidity of Cannabis abuse
I Cannabis
diagnosis+Heterotypic
comorbidity
) Cannabis diagnosis +
Homotypic comorbidity
I Cannabis diagnosis +
Homotypic comorbidity +
Heterotypic comorbidity
(184)
CANNABIS AND PSYCHIATRIC MORBIDITY
TABLE 4 : Psychiatric morbidity in patients abusing cannabis
Diagnosis
Cannabis induced psychosis
Schizophrenia
Delusional disorder
Other non organic psychotic disorders
B.A.D-mania with psychosis
B.A.D.- severe psychotic depression
Severe psychotic depression
Hypomania
Mild depression
Moderate depression
Other depressive disorder
Cyclothymia
Dysthymia
Generalized anxiety disorder
Adjustment reaction - prolonged depression
Trance and possession disorder
Dissocial Personality disorder
Pathological gambling
Exhibitionism
Mild Mental Retardation
Cannabis induced unspecified mental
& behavior disorder
Substance use/dependence only
Total
No. of cases
51
35
5
18
30
1
4
4
1
3
1
1
2
1
1
1
1
1
1
1
1
80
244
% (N=244)
21
14
2
7
12
0.4
2
2
0.4
1
0.4
0.4
1
0.4
0.4
0.4
0.4
0.4
0.4
0.4
0.4
34
100
also abusing alcohol and opioids was
coded under cannabis abuse and
polysubstance abuse respectively.
b) Independent psychiatric disorder
comorbidity (Heterotypic comorbidity)
Twenty-one heterotypic comorbid
psychiatric diagnoses were made for 164
patients (67%), i.e. having a comorbid
psychiatric disorder. Psychotic disorders
were experienced by 144 patients (88% of
Heterotypic comorbidity
I Paranoid psychosis
I Cannabis psychosis
I Affective psychosis
I Non-psychotic disorders
Heterotypic comorbidity of Cannabis
use
those with comorbid psychiatric disorders),
while 20 patients experienced a non-psychotic
illness (12%). The group of patients with
psychotic disorders was made up of those
suffering with paranoid psychosis including
schizophrenia (n=58; 40%), cannabis
psychosis (n=51; 35%) and affective
psychosis (n=35; 25%). Depressive and
anxiety disorders (n=9; 45%) were the
largest contributors to the numbers of those
with non-psychotic disorders.
Cannabis psychosis was the commonest
diagnosis amongst those with psychotic
disorders. Six different subtypes of cannabis
psychosis were diagnosed, the commonest
subtype being a mania-like psychosis (n=22)
with grandiose delusions, elated mood and
increased psychomotor activity. A
predominandy schizophrenia-like psychotic
state (n=8) and a predominandy delusional
state (n=6) were seen more often than a
further six cases of a predominantly
hallucinatory psychosis. Five subjects
presented with a polymorphic and rapidly
changing clinical picture characterized by
delusions, hallucinations and mood
disturbance, most commonly elation. A
further four cases displayed an admixture
of paranoia, grossly disorganized behavior,
fleeting hallucinations and delusions and
were diagnosed as mixed psychotic state.
The latter diagnosis was made by a process
of exclusion of other diagnostic subtypes.
Significandy, there was no case of a
predominandy depressive psychotic state
Psychotic disorders
I Cannabis psychosis
I Schizophrenia
I B.A.D. * Mania
I Other non-organic
psychosis
I Delusional disorder
I psychotic depression
I B.A.I). - Psychotic
depression
Psychotic disorders associated
with cannabis use
I Manic
I Schizophrenia-like
I Delusional
I Hallucinatory
I polymorphic
I Mixed
Subtypes ol cannabis psychosis
Subtypes of cannabis psychosis
that could be attributed to cannabis abuse.
Twelve patients with cannabis psychosis had
consumed substances other than cannabis
including alcohol (10 cases) and two cases
of polysubstance abuse/dependence. These
were diagnosed as cannabis psychosis
because of a temporal link between cannabis
use and onset of psychosis.
Treatment given
About half the patients (49.5%) received
antipsychotic medication (49.5%); twenty-
three patients (9%) received a mood-
stabilizing agent while 12 (%) were prescribed
antidepressants.
(185)
SARKAR t al
DISCUSSION
This study has a large patient sample of
chronic and heavy cannabis users coming
from a wide geographical catchment area
including urban, peri-urban, sub-rural, and
rural populations. The sample is
representative of all strata of the society.
The strengths of the study included data
collected at an academic institute with a
tradition of good record keeping and
diagnostic coding. A manual search in
addition to electronic search was carried out
to locate all case-notes thereby minimizing
the chances of missing cases. Down-rating
the aetiologies! role of cannabis in favour
of a functional diagnosis would have further
reduced any spurious attribution of mental
disorders solely to cannabis use.
a) Heterotypic Comorbidity
Our results suggest that heavy and chronic
use of cannabis can both cause a cannabis-
induced psychosis and be associated with
functional psychoses. Broadly, the nature
of psychosis associated with heavy cannabis
use is non-specific in that it includes both
paranoid and affective psychosis but also a
polymorphic disorder that cannot be
categorized within either of the two groups.
A smallet proportion of patients also
developed non-psychotic disorders. The
presence of a wide variety of psychiatric
disorders associated with cannabis abuse
therefore confirmed the study hypothesis.
The rate of psychiatric morbidity is
comparable to earlier reports [Troisi et al
1998, Weller and Halikas 1985].
b) Cannabis and Manic Psychosis
The most significant finding of the study
was the association of cannabis abuse with
development of manic disorder. Whilst
there are previous smaller reports of a
possible association between cannabis use
and mania, [Dhunjibhoy 1930, Rottanburg
et al 1982, Carney et al 1984, Harding and
Knight 1973] we believe that our study is
the first one to confirm this relationship in
a sizable number of patients. In our cohort,
some patients with a past history of mania
and cannabis abuse appeared to become
sensitized to the effects of cannabis over
a period of time so that for subsequent
episodes of mania there appeared to be a
progressive decrease in the time gap between
re-onset of cannabis use and onset of
mania. In other words, the relative
shortening of time to relapse following
reintroducrion of cannabis use in successive
episodes in this select group of patients
appeared analogous to the process of
'kindling' [Post et al 1989, Post et al 1982].
By 'hastening' manic relapses, cannabis
appeared to act as a precipitant, akin to the
"life-event stressor" first suggested as a
triggering mechanism in cases of
schizophrenia [Andreasson et al 1987]. The
association between cannabis abuse and
mania gains further support from a recent
study wherein cannabis use during follow-
up of 50 new-onset bipolar disorder patients
was associated with the experience of mania,
whilst alcohol abuse was linked to the
experience of depression [Strakowski et al
2000].
There may be possible biological
explanations for the association between
cannabis abuse and mania. Delta-9-
tetrahydrocannabinol (THC), the active
ingredient of cannabis, produces euphoria
[Brill and Nahas 1984]. Under laboratory
conditions high doses of THC have been
shown to produce visual and auditory
hallucinations, delusions, thought disorder
and symptoms of hypomania in normal
volunteers [Georgotas and Zeidenberg 1979].
Recent evidence also suggests that
cannabinoid receptors, especially CB-1,
located in substantia nigra, hippocampus,
cerebellum and striatum, may be
neuromodulatory by decreasing the uptake
of GABA and dopamine, thereby
potentiating their actions [D'Souza and
Kosten 2001]. Further prospective and
case-control studies, which control for other
substance misuse are needed to elucidate
this further.
ii) Cannabis Psychosis
Our results suggest that besides the
triggering effect of cannabis in established
bipolar disorders, cannabis psychoses can
also present as a manic episode. We also
found other psychotic presentations
suggesting that cannabis psychosis can
present as schizophrenia-like, predominantly
delusional or hallucinatory, as affective
psychosis or as a polymorphic and rapidly
changing psychosis. We could not confirm
the previous suggestions that the presence
of confusional state is a hallmark of cannabis
psychosis [Johns 2001, Chopra and Smith
1974, Chaudhry et al 1991, Tennant and
Groesbeck 1972, Goel and D'Netto 1975]
since only three patients in this study
displayed a confusional state. The DCR
position, which does not prioritize this
particular feature to a position of primacy
in making a diagnosis of cannabis psychosis,
is therefore validated.
iii) Cannabis and Schizophrenic
Psychosis
Our results confirm the association
between cannabis abuse and paranoid
psychoses, especially schizophrenia.
However, even some of these cases have
prominent affective features, consistent with
previous reports [Thacore and Shukla 1976,
Rottanburg et al 1982, Tsuang et al 1982].
In addition, in a substantial proportion of
our cases, only a diagnosis of 'other non-
organic psychotic disorders' (F29 category)
[World Health Organization 1993a] could be
made on account of bizarre symptomatology,
particularly grossly disorganized behavior.
Whilst the diagnosis of catatonic
schizophrenia had been made for several of
these patients by treating clinical teams, this
diagnosis was found unsupported by DCR
criteria, which specify that catatonic
symptoms are not diagnostic of
schizophrenia and may be provoked by
other aetiologies including alcohol or drugs
[World Health Organization 1993b].
b) Homotypic Comorbidity:
Cannabis has been known as a 'gateway
drug', and recent evidence suggests that
even after controlling for a wide range of
known risk factors for illicit drug use,
cannabis use is associated with an increased
risk of progression to other illicit drug use
[Fergusson and Horwood 2000]. Our study
confirms this since many subjects had
alcohol, opioid and polysubstance abuse
(186)
ANTIDEPRESSANT I N D U C E D
C A N N A B I S A N D PSYCHIATRIC M O R B I D I T Y
and dependence in this group. Cannabis
was die first drug of use in the substance
use life-trajectories of two-thirds of this
population, the remaining third starting with
alcohol or opioids. However, for two-thirds
of the whole cohort cannabis remained the
only drug of abuse. Whilst this may appear
contradictory to the foregoing, we believe
diat it is not inconsistent for people to
progress from cannabis use to other illicit
drugs in experimental ways, but to continue
to preferentially use cannabis in a dependant
manner, thereby confirming that in countries
such as India that have a tradition of
cannabis use, the widespread use of other
substances is limited [Basu et al 1994].
The study findings are limited by the
cohort being exclusively male, die lack of
corroborative urine samples, possible recall
bias and under-reporting by patients and,
lack of any structured assessments, leading
to reliance on case-note data alone.
CONCLUSIONS
Chronic and heavy abuse of cannabis in
hospital attending patients in India is
associated with widespread psychiatric
morbidity. The onset of cannabis use
begins at a relatively early age and heralds
the experimentation with other psychoactive
drugs. For the majority, however, cannabis
remains the only drug of abuse. Experience
of a psychotic illness is one of the major
adverse effects of heavy cannabis use,
particularly in those that present to
psychiatric hospitals. Whilst our study
confirms some of die earlier findings of
association of cannabis use and the
development of cannabis psychosis and
schizophrenia, most significandy it reveals
that heavy cannabis use can specifically
cause a mania-like psychosis and more
generally act as a precipitant for manic
relapse in bipolar patients.
REFERENCES
Andreasson, S., Allebeck, P., Engstrom, A.,
Rydberg, U. (1987) Cannabis and schizophrenia:
a longitudinal study of Swedish conscripts. Lancet,
(ii), 1483-1485.
Basu, D., Malhotra, A., Varma, V.K. (1994)
Cannabis related psychiatric syndromes: a selective
review. Indian Journal of Psychiatry, 36: 121-
128.
Basu, D., Malhotra, A., Bhagat, A., Varma,
V.K. (1999) Cannabis psychosis and acute
schizophrenia: a case-control study from India.
European Addiction Research, 5, 71-73.
Brill, H., Nahas, G.G. (1984) Cannabis
intoxication and mental illness. In: Nahas GG,
ed. Marijuana in Science and Medicine, pp. 263-
305. New York: Raven Press.
Carney, M.W.R, Bacelle, L., Robinson, B.
(1984) Psychosis after cannabis use. British
Medical Journal 288, 1047.
Chaudry, H.R., Moss, H..B., Bashir, A.,
Suliman.T (1991) Cannabis psychosis following
bhang ingestion. British Journal of Addiction, 86,
1075-1081.
Chopra, G., ft Smith, J. (1974) Psychotic
reactions following cannabis use in East Indians.
Archives of General Psychiatry, 23, 193-198
Degenhardt, L., Wayne, H & Lynskey,M.
(2001) Alcohol, cannabis and tobacco use
among Australians: a comparison of their
associations with other drug use and use disorders,
affective and anxiety disorders and psychosis.
Addiction 96, 1603-1614.
Dhunjibhoy, J.E. (2001) A brief resume of the
types of insanity commonly met within India with
full description of "Indian Hemp Insanity"
peculiar to the country. Journal of Mental
Science 1930; 76: 254-264. D'Souza DC, Kosten
TR. Cannabinoid antagonists: a treatment in
search of an illness. Archives of General
Psychiatry, 58, 330-331.
Fergusson, D.M., ft Horwood, L.J. (2000)
Cannabis use and dependence in a New Zealand
birth cohort New Zealand Medical Journal, 113,
56-58.
Georgotas, A., & Zeidenberg, R (1979)
Observations on the effects of four weeks of
heavy marijuana smoking on group interaction
and individual behavior. Comprehensive Psychiatry.
20, 427-432.
Ghodse, H. (1986) Cannabis psychosis. British
Journal of Addiction, 81. 473-478.
Goel, D.S., & DNetto.T.P. (1975) Cannabis:
die habit and psychosis. Indian Journal of
Psychiatry, 17, 238.
Grinspoon, L., ft Bakalar, J.B. (1993)
Marihuana, The Forbidden Medicine. New Haven:
Yale University Press.
Hall, W , Johnston, L , Donnelly, N . (1999)
The epidemiology of cannabis use and its
consequences. In: Kalant H, Corrigall W, Hall
W, Smart R , eds. The Health Effects of
Cannabis (pp 69-125). Toronto: Addiction
Research Foundation.
Harding, T., & Knight, F. (1973) Marihuana-
modified mania. Archives of General Psychiatry,
29: 635-637.
Indian Hemp Drugs Commission Report
(1894) Simla: IHDC
Johns, A . (2001) Psychiatric effects of cannabis.
British Journal of Psychiatry, 178, 116-122.
National Institute of Social Defense (1992)
Drug abuse - summaries of research studies.
New Delhi: Ministry of Defence, Govt, of India.
Post. R.M., Uhde, T.W., Putnam, F.W.,
Ballenger, J.C., Berrettini, W . H . (1982)
Kindling and carbamazepine in affective illness.
Journal of Nervous and Mental Disease, 170,717-
730.
Post, R.M. & Weiss, S.R. (1989) Sensitization,
kindling and anticonvulsants in mania. Journal
of Clinical Psychiatry, 50 (suppl), 45-47.
Rottanburg, D., Robins, A., Ben-Arie, O., et
al (1982) Cannabis associated psychosis with
hypomanic features. Lancet, 2, 1364-1366.
Strakowski, S.M. Delbello, M.P., Fleck.D.E.,
Arndt, S. (2000) The impact of substance
misuse on the course of bipolar disorder.
Biological Psychiatry; 48: 477-485.
Talbott, J.A. ft Teague, j . W . (1969) Marijuana
psychosis. Journal of the American Medical
Association, 210, 299-302.
Tennant, F.S., & Groesbeck, C.J. (1972)
Psychiatric effects of hashish. Archives of General
Psychiatry, 27. 33-136.
Thacore, V.R., & Shukla, S.R.P. (1976)
Cannabis psychosis and paranoid schizophrenia.
Archives of General Psychiatry; 27: 133-136.
Thomas, M.(I993) Psychiatric symptoms in
cannabis users. British Journal of Psychiatry; 163:
141-149.
Thomas, H. (1996) A community survey of
adverse effects of cannabis use. Drug and
Alcohol Dependence, 42, 201-207.
Troisi, A., Pasini, A., Saracco, M., Spalletta,
G. (1998) Psychiatric symptoms in male cannabis
users not using other illicit drugs. Addiction, 93,
487-492.
Tsuang, M., Simpson, J., Kronfol, Z. (1982)
Subtypes of drug abuse with psychosis. Archives
of General Psychiatry, 39, 141-147.
Weller, R.A., & Halikas, J.A. (1985) Marijuana
use and psychiatric illness: a follow-up study.
American Journal of Psychiatry, 142. 848-850.
(187)
SARKAR at al
W o r l d Health Organization (1993a)
Schedules for Clinical Assessments in
Neuropsychiatry, version 2, Glossary. Geneva:
World Health Organization.
World Health Organization (1993b) The
ICD-IO classification of mental and behavioral
disorders:Oiagnostic criteria for research. Geneva:
World Health Organization.
World Health Organization (1993c) The
ICD-IO classification of mental and behavioral
disorders: Clinical descriptions and diagnostic
guidelines. Geneva: World Health Organization.
JAYDIP SARKAR, Specialist Registrar in Forensic Psychiatry, Shaftesbury Clinic, Springfield University Hospital, London, SWI7 7DJ, U.K.
PRATIMA MURTHY*, Associate Professor of Psychiatry, National Institute of Mental Health & Neuro Sciences, Hosur Road, Bangalore, 560029, India.
SWARAN P SINGH, Senior Lecturer in Community Psychiatry, Department of General Psychiatry, St George's Hospital Medical School, Blackshaw Road,
London, SWI7 ORE, U.K.
* Correspondence
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