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CANNABIS USE AND AGE OF ONSET IN FIRST EPISODE OF PSYCHOSIS: A GENDER ISSUE?
Abstracts of the 3rd Biennial Schizophrenia International Research Conference / Schizophrenia Research 136, Supplement 1 (2012) S1–S375
other drugs]) was carried out in order to check the significance of these two fixed factors on IQ and WTAR. Finally, we compared IQ and pre-morbid IQ between “affective” and “non affective” psychosis by cannabis use. Patients performed significantly worse than controls in IQ (p<0.0001) and premorbid IQ (p<0.0001). ANCOVAs showed significant higher IQ (p=0.001) and pre-morbid IQ (p=0.011) in people who smoked cannabis lifetime in the case group and no differences in control sample, either in IQ (p=0.757) and in WTAR scores (p=0.156). Factorial ANCOVAs confirmed that FEP group was significantly affected by drug on IQ (p=0.006). Interestingly, there was not significant differences in WTAR between cases and controls if they had used only cannabis lifetime (p=0.284). This suggests that patients who used only cannabis lifetime were more similar in pre-morbid IQ to controls. Drug use, considered alone, was more important than diagnosis in determining cognitive differences between subjects, especially in non affective psychosis. Our results confirm a strong relationship between cannabis use lifetime and higher cognitive performance in patients. First episode subject who used only cannabis lifetime seem to be a high pre-morbid functioning sub-group, which does not show significant differences with control group. Non affective psychosis is the most impaired diagnostic group, although people in this group with cannabis use lifetime show a significantly higher pre-morbid IQ than others, more similar to affective psychosis group. These findings confirm a different relationship of cannabis with cognitive function in FEP patients and controls, and in different diagnostic groups. They also suggest that the relationship between higher cognitive functioning and cannabis use could be read in the direction of pre-existing less impaired cognitive functioning in which cannabis could be a marker of a better pre-morbid social functioning.
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many different ingredients, with different mechanisms of action. Delta9-tetrahydrocannabinol (delta-9-THC), the main psychoactive ingredient is responsible for its psychotogenic effects, while Cannabidiol (CBD), the other major ingredient has anxiolytic and possibly antipsychotic effects. The purpose of this symposium is to showcase recent evidence regarding the neural and behavioural effects of these cannabinoids, and relate this to the potential role of the endocannabinoid system in the pathophysiology and treatment of schizophrenia. The symposium will be chaired by Prof Philip McGuire, who has carried out a series of genetic, psychopathological and neuroimaging studies of the effects of cannabis in relation to psychosis. Dr Paul Morrison will present data on the effects of delta-9-THC on brain electrical activity in healthy volunteers, and how this relates to its acute induction of psychotic symptoms. Dr Sagnik Bhattacharyya will review the effects of delta-9-THC and CBD on neural activity during learning, inhibitory, salience and fear processing tasks, as studied using functional MRI, with particular reference to their different effects on the neural substrate of psychotic and anxiety symptoms. Dr Jose Crippa will present data from a range of studies including experimental symptom-induction studies and studies in clinical populations that suggest that CBD has antipsychotic properties. Prof Markus Leweke will present data from a twin sample that suggests that vulnerability to psychosis is associated with alterations in components of the endocannbinoid system. Prof Shitij Kapur will discuss the implications of these studies for our understanding of the neurobiology of schizophrenia, and for the development if novel treatments.
CANNABIS, CNS RHYTHMS & POSITIVE PSYCHOTIC SYMPTOMS
CANNABIS USE AND AGE OF ONSET IN FIRST EPISODE OF PSYCHOSIS: A GENDER ISSUE? Fabio Allegri 1,2 1 University of Bologna, Bologna, Italy/; 2 Institute of Psychiatry, King’s College, London, United Kingdom Substance use is related to psychiatric disorders and the rate differ as a function of many factors, including gender. This paper aims to investigate whether the use of cannabis in comorbidity or not with other substances has a different impact on the age at onset of psychosis in male and female. Methods: We used information on cannabis use and age at onset from 511 and 163 cases presenting with a first episode of psychosis to the South London & Maudsley National Health Service (NHS) Foundation Trust and to the West Bologna area Health Centres respectively. Cases were divided by gender and cannabis use in comorbidity or not with other drugs. Results: Users had an earlier age of onset of psychosis (2-7 years earlier); distinguishing the cases by gender and comorbid use of cannabis with other drugs or not, men showed an earlier age of onset compared to the non user group (p=0.01). Women who consumed only cannabis don’t anticipate the onset, except at a very young age, while they showed an early onset if they use cannabis together with other substances. By analyzing the frequency of use, there was a dose-dependent effect in the male group; this relation between the pattern of use and the frequency of psychosis was not present in the female group (p<0.001). Discussion: While in men cannabis use is always related to an earlier onset compared to non-users, early onset occurs in women only if cannabis is consumed with other drugs. Moreover there’s a correlation between the frequency of cannabis use and the rate age of onset only in the male group. Females don’t have a relevant dose-dependent effect.
Workshop CANNABIS AND PSYCHOSIS – THE STATE OF THE ART Chairpersons: Philip K. McGuire and Jim van Os Discussant: Shitij Kapur Sunday, 15 April 2012 6:30 pm – 8:30 pm Overall Abstract: Epidemiological studies link regular use of cannabis, particularly in young people, with an increased risk of schizophrenia. However, the underlying biological mechanism is unclear. The cannabis plant has
Paul Morrison, J.M. Stone, S. Bhattacharyya, J. Nottage, R.M. Murray, P. McGuire, S. Kapur, D. Ffythche Department of Psychosis Studies, Institute of Psychiatry, King’s College London, London, United Kingdom The main ingredient in cannabis, -9-tetrahydrocannabinol (THC) can elicit acute psychotic reactions in healthy individuals and precipitate relapse in schizophrenic patients, but the underlying mechanism is unknown [1]. Animal work has shown that THC changes the dynamics of brain networks as reflected in neural oscillations, and that such changes have functional consequences [2]. Similarly, as recorded in the scalp electroencephalogram (EEG), brain network dynamics are altered in schizophrenia with specific changes in patients with psychotic symptoms [3]. Hence, we tested the hypothesis that THC-psychosis is related to changes in the dynamics of brain networks as reflected in EEG power and coherence. Method: A within-groups design. Healthy participants (n=16) received intravenous THC (1.25mg) or placebo during EEG recording. Traces were collected during engagement of the central executive in the n-back task of working-memory (WM). EEG data was analysed for power and coherence in the bands; delta (1-3.5Hz), theta (3.5-7Hz), alpha (8-13Hz) & beta (14-25Hz), using fast-Fourier transform. Coherence was measured as the cross-spectrum between two bipolar channels: Left fronto-parietal F3/F5-PO3/PO5; Right fronto-parietal F4/F6-PO4/PO6; and Bi-frontal F3/F5-F4/F6. Psychosis was rated by an independent psychiatrist using the PANSS scale. Differences between THC v placebo were analysed by repeated-measures ANOVA or Friedman’s test. Correlations between the most robust EEG-markers of THC and psychological outcomes were analysed by Spearman’s rho. Bonferroni corrections were applied. Compared to placebo, THC evoked positive psychotic symptoms, as measured by the PANSS scale (p<0.001) and slowed WM performance (p<0.05). Under THC, theta power was reduced (p<0.001) regardless of n-back demand, but showed no relationship with psychotic symptoms or WM impairment. Coherence between bi-frontal electrodes in the theta band was reduced by THC (p<0.05) and reductions correlated with positive psychotic symptoms (rho=0.79, p<0.001). Bi-frontal specificity was suggested by the absence of a relationship between psychotic symptoms and (left or right) fronto-parietal coherence. Global theta power was reduced by THC, without any manifest psychological consequences. In contrast, there was a strong and specific association between THC-induced positive psychotic symptoms and reduced bi-frontal theta coherence. Impaired functional “cross-talk” between the frontal lobes in the theta band might account for the pro-psychotic effects of THC/cannabis. References: [1] Murray RM, Morrison PD, Henquet C, Di Forti M (2007). Cannabis, the mind and society: the hash realities. Nat Rev Neurosci 8: 885-895.
other drugs]) was carried out in order to check the significance of these two fixed factors on IQ and WTAR. Finally, we compared IQ and pre-morbid IQ between “affective” and “non affective” psychosis by cannabis use. Patients performed significantly worse than controls in IQ (p<0.0001) and premorbid IQ (p<0.0001). ANCOVAs showed significant higher IQ (p=0.001) and pre-morbid IQ (p=0.011) in people who smoked cannabis lifetime in the case group and no differences in control sample, either in IQ (p=0.757) and in WTAR scores (p=0.156). Factorial ANCOVAs confirmed that FEP group was significantly affected by drug on IQ (p=0.006). Interestingly, there was not significant differences in WTAR between cases and controls if they had used only cannabis lifetime (p=0.284). This suggests that patients who used only cannabis lifetime were more similar in pre-morbid IQ to controls. Drug use, considered alone, was more important than diagnosis in determining cognitive differences between subjects, especially in non affective psychosis. Our results confirm a strong relationship between cannabis use lifetime and higher cognitive performance in patients. First episode subject who used only cannabis lifetime seem to be a high pre-morbid functioning sub-group, which does not show significant differences with control group. Non affective psychosis is the most impaired diagnostic group, although people in this group with cannabis use lifetime show a significantly higher pre-morbid IQ than others, more similar to affective psychosis group. These findings confirm a different relationship of cannabis with cognitive function in FEP patients and controls, and in different diagnostic groups. They also suggest that the relationship between higher cognitive functioning and cannabis use could be read in the direction of pre-existing less impaired cognitive functioning in which cannabis could be a marker of a better pre-morbid social functioning.
S25
many different ingredients, with different mechanisms of action. Delta9-tetrahydrocannabinol (delta-9-THC), the main psychoactive ingredient is responsible for its psychotogenic effects, while Cannabidiol (CBD), the other major ingredient has anxiolytic and possibly antipsychotic effects. The purpose of this symposium is to showcase recent evidence regarding the neural and behavioural effects of these cannabinoids, and relate this to the potential role of the endocannabinoid system in the pathophysiology and treatment of schizophrenia. The symposium will be chaired by Prof Philip McGuire, who has carried out a series of genetic, psychopathological and neuroimaging studies of the effects of cannabis in relation to psychosis. Dr Paul Morrison will present data on the effects of delta-9-THC on brain electrical activity in healthy volunteers, and how this relates to its acute induction of psychotic symptoms. Dr Sagnik Bhattacharyya will review the effects of delta-9-THC and CBD on neural activity during learning, inhibitory, salience and fear processing tasks, as studied using functional MRI, with particular reference to their different effects on the neural substrate of psychotic and anxiety symptoms. Dr Jose Crippa will present data from a range of studies including experimental symptom-induction studies and studies in clinical populations that suggest that CBD has antipsychotic properties. Prof Markus Leweke will present data from a twin sample that suggests that vulnerability to psychosis is associated with alterations in components of the endocannbinoid system. Prof Shitij Kapur will discuss the implications of these studies for our understanding of the neurobiology of schizophrenia, and for the development if novel treatments.
CANNABIS, CNS RHYTHMS & POSITIVE PSYCHOTIC SYMPTOMS
CANNABIS USE AND AGE OF ONSET IN FIRST EPISODE OF PSYCHOSIS: A GENDER ISSUE? Fabio Allegri 1,2 1 University of Bologna, Bologna, Italy/; 2 Institute of Psychiatry, King’s College, London, United Kingdom Substance use is related to psychiatric disorders and the rate differ as a function of many factors, including gender. This paper aims to investigate whether the use of cannabis in comorbidity or not with other substances has a different impact on the age at onset of psychosis in male and female. Methods: We used information on cannabis use and age at onset from 511 and 163 cases presenting with a first episode of psychosis to the South London & Maudsley National Health Service (NHS) Foundation Trust and to the West Bologna area Health Centres respectively. Cases were divided by gender and cannabis use in comorbidity or not with other drugs. Results: Users had an earlier age of onset of psychosis (2-7 years earlier); distinguishing the cases by gender and comorbid use of cannabis with other drugs or not, men showed an earlier age of onset compared to the non user group (p=0.01). Women who consumed only cannabis don’t anticipate the onset, except at a very young age, while they showed an early onset if they use cannabis together with other substances. By analyzing the frequency of use, there was a dose-dependent effect in the male group; this relation between the pattern of use and the frequency of psychosis was not present in the female group (p<0.001). Discussion: While in men cannabis use is always related to an earlier onset compared to non-users, early onset occurs in women only if cannabis is consumed with other drugs. Moreover there’s a correlation between the frequency of cannabis use and the rate age of onset only in the male group. Females don’t have a relevant dose-dependent effect.
Workshop CANNABIS AND PSYCHOSIS – THE STATE OF THE ART Chairpersons: Philip K. McGuire and Jim van Os Discussant: Shitij Kapur Sunday, 15 April 2012 6:30 pm – 8:30 pm Overall Abstract: Epidemiological studies link regular use of cannabis, particularly in young people, with an increased risk of schizophrenia. However, the underlying biological mechanism is unclear. The cannabis plant has
Paul Morrison, J.M. Stone, S. Bhattacharyya, J. Nottage, R.M. Murray, P. McGuire, S. Kapur, D. Ffythche Department of Psychosis Studies, Institute of Psychiatry, King’s College London, London, United Kingdom The main ingredient in cannabis, -9-tetrahydrocannabinol (THC) can elicit acute psychotic reactions in healthy individuals and precipitate relapse in schizophrenic patients, but the underlying mechanism is unknown [1]. Animal work has shown that THC changes the dynamics of brain networks as reflected in neural oscillations, and that such changes have functional consequences [2]. Similarly, as recorded in the scalp electroencephalogram (EEG), brain network dynamics are altered in schizophrenia with specific changes in patients with psychotic symptoms [3]. Hence, we tested the hypothesis that THC-psychosis is related to changes in the dynamics of brain networks as reflected in EEG power and coherence. Method: A within-groups design. Healthy participants (n=16) received intravenous THC (1.25mg) or placebo during EEG recording. Traces were collected during engagement of the central executive in the n-back task of working-memory (WM). EEG data was analysed for power and coherence in the bands; delta (1-3.5Hz), theta (3.5-7Hz), alpha (8-13Hz) & beta (14-25Hz), using fast-Fourier transform. Coherence was measured as the cross-spectrum between two bipolar channels: Left fronto-parietal F3/F5-PO3/PO5; Right fronto-parietal F4/F6-PO4/PO6; and Bi-frontal F3/F5-F4/F6. Psychosis was rated by an independent psychiatrist using the PANSS scale. Differences between THC v placebo were analysed by repeated-measures ANOVA or Friedman’s test. Correlations between the most robust EEG-markers of THC and psychological outcomes were analysed by Spearman’s rho. Bonferroni corrections were applied. Compared to placebo, THC evoked positive psychotic symptoms, as measured by the PANSS scale (p<0.001) and slowed WM performance (p<0.05). Under THC, theta power was reduced (p<0.001) regardless of n-back demand, but showed no relationship with psychotic symptoms or WM impairment. Coherence between bi-frontal electrodes in the theta band was reduced by THC (p<0.05) and reductions correlated with positive psychotic symptoms (rho=0.79, p<0.001). Bi-frontal specificity was suggested by the absence of a relationship between psychotic symptoms and (left or right) fronto-parietal coherence. Global theta power was reduced by THC, without any manifest psychological consequences. In contrast, there was a strong and specific association between THC-induced positive psychotic symptoms and reduced bi-frontal theta coherence. Impaired functional “cross-talk” between the frontal lobes in the theta band might account for the pro-psychotic effects of THC/cannabis. References: [1] Murray RM, Morrison PD, Henquet C, Di Forti M (2007). Cannabis, the mind and society: the hash realities. Nat Rev Neurosci 8: 885-895.