A clinical comparison of schizophrenia with and without pre-onset cannabis use disorder: a retrospective cohort study using categorical and dimensional approaches
Sarrazin et al. Ann Gen Psychiatry
A clinical comparison of schizophrenia with and without pre-onset cannabis use disorder: a retrospective cohort study using categorical and dimensional approaches
Samuel Sarrazin 0 2 3
Florence Louppe 0 3
Raphael Doukhan 0 3
Franck Schürhoff 0 1 2 3 4
0 AP-HP, DHU PePSY, Hôpitaux universitaires Henri-Mondor, Pôle de Psychiatrie et d'Addictologie , 94000 Créteil , France
1 Faculté de Médecine, Université Paris-Est , 94000 Créteil , France
2 INSERM U955 , Equipe 15, IMRB, 94000 Créteil , France
3 AP-HP, DHU PePSY, Hôpitaux universitaires Henri-Mondor, Pôle de Psychiatrie et d'Addictologie , 94000 Créteil , France
4 FondaMental Fondation, Fondation de coopération scientifique , 94000 Créteil , France
Background: A high prevalence of cannabis use disorder has been reported in subjects suffering from schizophrenia, fuelling intense debate about whether schizophrenia with pre-onset cannabis use disorder may be a distinct entity with specific features or whether cannabis use disorder can precipitate schizophrenia in genetically vulnerable subjects. Methods: We retrospectively assessed schizophrenia subjects with and without pre-onset cannabis use disorder on the basis of their clinical features, assessed categorically and dimensionally with the operational criteria checklist for psychotic illnesses (OCCPI). We also investigated whether the two groups could be differentiated on the basis of a history of psychiatric disorders in first-degree relatives. A principal component factor analysis of the OCCPI items was used to identify specific symptom dimensions. The relationships between symptom dimensions and cannabis status were analysed by point-biserial correlation analysis to control for sex and age at time of the assessment and illness duration. Results: One hundred and seventy-one subjects with a diagnosis of schizophrenia were included. Among them, forty-one patients (18.2 % of the sample) had a cannabis use disorder before or at the time of the onset of schizophrenia. We found similar results in symptoms patterns or family history between patients with and without pre-onset cannabis use disorder. Conclusions: Our results clearly argue against cannabis-associated schizophrenia being a relevant distinct clinical entity of schizophrenia with specific features.
Schizophrenia; Psychosis; Cannabis; Symptom dimension; OCCPI
Background
A high prevalence of cannabis use has repeatedly been
reported in psychotic patients [
1
]. Previous systematic
reviews have reported a wide range (13–45 %) in the rates
of cannabis use disorders (CUD) in schizophrenia users
[
2, 3
], with a median lifetime rate estimated at 27.1 %
[4]. Apart from the fact that acute intoxication can lead
to ‘psychotic-like’ experiences that do not persist beyond
the period of intoxication [
5
], various possibilities have
been discussed for the association between cannabis
and schizophrenia which include: (a) cannabis use is a
component cause of schizophrenia; (b) the hypothesis of
“self-medication” for symptoms of psychiatric diseases
such as the negative symptoms of schizophrenia, anxiety,
depression or dysphoria and (c) common
socio-demographic factors and shared genetic factors.
Several studies have shown that the use of cannabis
leads to physiological and cognitive deficits of a similar
nature to those seen in schizophrenia [
6
]. In particular,
there is an increasing body of evidence demonstrating
that cannabis users (without schizophrenia) show
deficits in tasks of sustained attention, working memory and
other executive functions [
7
], as well as abnormalities in
automatic processing of auditory stimuli: P50
suppression [
8
], prepulse inhibition (PPI) [
9
] and the mismatch
negativity (MMN) [
10
] of the event-related potential
(ERP). This suggests that dysfunctions in the
endocannabinoid system could be involved in the development of
similar deficits associated with cannabis use and
schizophrenia, and further proposes that the neurobiology
underpinning the development of electrophysiological/
cognitive deficits in cannabis users may overlap with the
neurobiological underpinnings of schizophrenia.
Other data suggest that the link between cannabis
use and schizophrenia might be causal, even if a direct
cause–effect relationship between the two disorders has
not been clearly established. Systematic reviews
regarding the association between cannabis and psychosis have
suggested that cannabis can increase the lifetime risk of
psychosis by a factor of two or three [
11–13
] and
metaanalytic approaches found that the risk of psychosis was
approximately 40 % higher in cannabis users than in
nonusers [
14
]. In the causal hypothesis, cannabis use may be
directly involved in the pathophysiological processes that
lead to a distinct form of schizophrenia-spectrum
disorder that would have never happened otherwise. This is
different from the hypothesis in which cannabis use may
act (...truncated)