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P.3.b.001 Cannabis use and psychotic experiences in UK teenagers – a longitudinal study
P.3.b. Psychotic disorders and antipsychotics − Psychotic disorders (basic) successive string; the colors being presented in an unpredictable sequence, forcing the subject to decide which rule to apply trial by trial. In the present study, 41 healthy volunteers aged 21 to 55 years performed the RST on three study days alongside Parts A and B of the trail making test (TMT). Part A of the TMT involves a single rule, while Part B involves rule switching. Analysis of variance was used to compare the performance between the various phases of the RST and correlations were run to establish testretest reliability and examine relationships between the two tests and performance with the age of the volunteers. Further studies using the same methodology are underway using schizophrenic and bipolar patients. Results: In the RST, the subjects took significantly longer to respond in the switching phase than when performing the task using either one of the rules (p < 0.001), this performance change reflecting the demands of rule switching and providing an assessment of executive control. The test-retest reliability of the speed scores in the switching and nonswitching conditions of the RST was good (r = 0.58 to 0.89), as was that for Parts A and B of the TMT (r = 0.60 to 0.87). There were also statistically significant correlations between the RST switching condition and Part B of the TMT (r = 0.37, p < 0.02), as well as between the extra response time in the switching condition of the RST and the longer completion time of the TMT Part B (r = 0.32, p < 0.05). Further, the extra response time in the switching condition of the RST correlated with the age of the volunteers (r = 0.5, p < 0.001), indicating that the test is sensitive to age-related declines. Discussion: The RST appears to be suitable for repeatedly assessing executive control over time in clinical trials with volunteers. Data from a validation trial in schizophrenia currently underway will also be presented. References [1] DiGirolamo GJ et al. (2001). General and task-specific frontal lobe recruitment in older adults during executive processes: A fMRI investigation of task-switching. NeuroReport 12: 2065–2071. Disclosure statement: I am employed by Bracket who offer the test described in this paper as a service in clinical trials.
P.3.b. Psychotic disorders and antipsychotics − Psychotic disorders (basic) P.3.b.001 Cannabis use and psychotic experiences in UK teenagers − a longitudinal study S. Gage1 ° , M. Hickman1 , J. Heron1 , M. Munaf`o2 , S. Zammit3 of Bristol, School of Social and Community Medicine, Bristol, United Kingdom; 2 University of Bristol, Experimental Psychology, Bristol, United Kingdom; 3 University of Cardiff, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff, United Kingdom
1 University
Purpose of the study: A consistent association between cannabis use and psychotic experiences (PEs) has been described in previous literature, but confounding by childhood characteristics has been only partially adjusted for in most studies. We aimed to investigate the association between cannabis use and incidence of PEs with more extensive consideration of potential confounders. Methods used: We used data from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort (N = 3303).
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Substance use at age 16 was assessed via self-report questionnaire. PEs at age 18 were assessed via semi-structured interviews, where cross-questioning was allowed to ensure that experiences reported were coded as accurately as possible. Confounders (family history, IQ, depression, borderline personality traits, SDQ (strengths and difficulties), and other illicit drug use) were measured variously by questionnaire and interview. Due to collinearity between cannabis use and tobacco use, a separate analysis for tobacco use at age 16 was conducted. Logistic regression analyses were conducted to investigate the associations between cannabis use at 16 and PEs at 18, and tobacco use at 16 and PEs at 18. Results: We observed a strong association between cumulative use of cannabis at 16 and PEs at 18 (OR: 1.48, 95% CI: 1.29, 1.71) that was relatively unchanged when adjusting for maternal and childhood confounders (adjusted OR: 1.52, 95% CI: 1.24, 1.85). Associations were greatly attenuated by adjustment for other illicit drug use (fully adjusted OR 1.21, 95% CI: 0.93, 1.58), though independent effects of cannabis and other drugs was difficult to determine due to their collinearity. Frequency of tobacco use was also associated with PEs. However, this relationship did not attenuate to the same degree when other illicit drug use at baseline was adjusted for (fully adjusted OR 1.31, 95% CI: 1.06, 1.62). There were 85 individuals who smoked cannabis with tobacco even though they rated themselves as non-smokers when asked about tobacco use. Conclusions: The association between cannabis and PEs was robust to confounding by childhood characteristics, but further study is required to examine potential confounding by other substances, including tobacco. The association between tobacco and PEs was also robust to childhood confounding, but again there was weaker evidence for an association when other drug use was added to the model. Although there has been a strong consistent relationship between cannabis and PEs, this relationship remains much less clear in relation to long-term effects on psychosis. Further analyses of these data are required to tease apart these recreational drugs and their effects upon PEs. In particular a more nuanced approach is necessary to tease apart effects from cannabis and tobacco. Future work will utilise novel approaches such as Mendelian Randomisation to investigate causal effects of tobacco on PEs independently of confounding by cannabis use and other illicit drug use.
P.3.b.002 A dual rat model of schizophrenia reveals deficiencies in the gene and protein expression at the medial prefrontal cortex and amygdala J. Gilabert-Juan1 ° , A.R. Saez2 , H. Carceller2 , M. Belles2 , M.D. Molto3 , J. Nacher1 1 Universitat de Val`encia, Department of Cell Biology. CIBERSAM. INCLIVA, Burjassot (Valencia), Spain; 2 Universitat de Val`encia, Department of Cell Biology, Burjassot (Valencia), Spain; 3 Universitat de Val`encia, Department of Genetics. CIBERSAM. INCLIVA, Burjassot (Valencia), Spain The neurobiological basis of schizophrenia, one of the most studied psychiatric disorders, is still far from being understood due to the elevated complexity of the disease, the high variability of the symptoms and signs shown by the patients and because of its genetic and environmental character. Modeling schizophrenia is a convoluted issue too. Different animal models reproduce some of the schizophrenia traits, but all of them also fail to reproduce
P.3.b. Psychotic disorders and antipsychotics − Psychotic disorders (basic) P.3.b.001 Cannabis use and psychotic experiences in UK teenagers − a longitudinal study S. Gage1 ° , M. Hickman1 , J. Heron1 , M. Munaf`o2 , S. Zammit3 of Bristol, School of Social and Community Medicine, Bristol, United Kingdom; 2 University of Bristol, Experimental Psychology, Bristol, United Kingdom; 3 University of Cardiff, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff, United Kingdom
1 University
Purpose of the study: A consistent association between cannabis use and psychotic experiences (PEs) has been described in previous literature, but confounding by childhood characteristics has been only partially adjusted for in most studies. We aimed to investigate the association between cannabis use and incidence of PEs with more extensive consideration of potential confounders. Methods used: We used data from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort (N = 3303).
S315
Substance use at age 16 was assessed via self-report questionnaire. PEs at age 18 were assessed via semi-structured interviews, where cross-questioning was allowed to ensure that experiences reported were coded as accurately as possible. Confounders (family history, IQ, depression, borderline personality traits, SDQ (strengths and difficulties), and other illicit drug use) were measured variously by questionnaire and interview. Due to collinearity between cannabis use and tobacco use, a separate analysis for tobacco use at age 16 was conducted. Logistic regression analyses were conducted to investigate the associations between cannabis use at 16 and PEs at 18, and tobacco use at 16 and PEs at 18. Results: We observed a strong association between cumulative use of cannabis at 16 and PEs at 18 (OR: 1.48, 95% CI: 1.29, 1.71) that was relatively unchanged when adjusting for maternal and childhood confounders (adjusted OR: 1.52, 95% CI: 1.24, 1.85). Associations were greatly attenuated by adjustment for other illicit drug use (fully adjusted OR 1.21, 95% CI: 0.93, 1.58), though independent effects of cannabis and other drugs was difficult to determine due to their collinearity. Frequency of tobacco use was also associated with PEs. However, this relationship did not attenuate to the same degree when other illicit drug use at baseline was adjusted for (fully adjusted OR 1.31, 95% CI: 1.06, 1.62). There were 85 individuals who smoked cannabis with tobacco even though they rated themselves as non-smokers when asked about tobacco use. Conclusions: The association between cannabis and PEs was robust to confounding by childhood characteristics, but further study is required to examine potential confounding by other substances, including tobacco. The association between tobacco and PEs was also robust to childhood confounding, but again there was weaker evidence for an association when other drug use was added to the model. Although there has been a strong consistent relationship between cannabis and PEs, this relationship remains much less clear in relation to long-term effects on psychosis. Further analyses of these data are required to tease apart these recreational drugs and their effects upon PEs. In particular a more nuanced approach is necessary to tease apart effects from cannabis and tobacco. Future work will utilise novel approaches such as Mendelian Randomisation to investigate causal effects of tobacco on PEs independently of confounding by cannabis use and other illicit drug use.
P.3.b.002 A dual rat model of schizophrenia reveals deficiencies in the gene and protein expression at the medial prefrontal cortex and amygdala J. Gilabert-Juan1 ° , A.R. Saez2 , H. Carceller2 , M. Belles2 , M.D. Molto3 , J. Nacher1 1 Universitat de Val`encia, Department of Cell Biology. CIBERSAM. INCLIVA, Burjassot (Valencia), Spain; 2 Universitat de Val`encia, Department of Cell Biology, Burjassot (Valencia), Spain; 3 Universitat de Val`encia, Department of Genetics. CIBERSAM. INCLIVA, Burjassot (Valencia), Spain The neurobiological basis of schizophrenia, one of the most studied psychiatric disorders, is still far from being understood due to the elevated complexity of the disease, the high variability of the symptoms and signs shown by the patients and because of its genetic and environmental character. Modeling schizophrenia is a convoluted issue too. Different animal models reproduce some of the schizophrenia traits, but all of them also fail to reproduce