title: Examining the Association between Cannabis Use and Working Memory, Processing Speed, and Sub-Psychotic Subjective Experiences

authors: Vaka, Wabuya

subjects: Cannabis

abstract: New Zealand has among the top two highest prevalence of cannabis use in the world. Additionally, the strings of cannabis on offer in the market of New Zealand is among the most potent ones available. With these two factors at play within New Zealand society, it is important to know the effects of cannabis on mental health. Studies have suggested that regular/heavy use of cannabis can lead to psychosis, however other studies have presented findings contrary to this. Studies consistently found that individuals with psychosis performed much poorer on working memory measure via the digit-symbol subset of the WAIS. Thus this study aimed to investigate how cannabis use may relate with performance of digit-symbol performance and sub-clinical psychotic experiences.
Method: A quantitative design was used to investigate relationships:  between cannabis use, digit-symbol performance, and ratings of the Sub-Psychotic Subjective Experiences Scale (SPSES). Fifty one voluntary random sample participants (n=51) were included in the results of the study. 69% were aged 18-24 years, 84% of the sample population were students, and majority Europeans. Males and females were equally represented. The research sessions were conducted in an office-type laboratory environment. The first part entailed participants completing Wechsler Abbreviated Scale of Intelligence 2nd edition (WASI-II), and Wechsler Adult Intelligence Scale 3rd edition (WAIS-III) digit-symbol subtest with the researcher on a desk. Participants then moved to the computer to complete the questionnaires on background and history, cannabis use (Cannabis Use Problem Identification Test (CUPIT) and Cannabis Abuse Screening Test (CAST) questionnaires for cannabis users), and the Sub-Psychotic Subjective Experiences (SPSES) questionnaire.
Results: Participants were apportioned into four cannabis use groups using self-rating measures obtained from CUPIT and CAST scores. The user groups were 1: non-users, 2: previous uses, 3: non-regular users, and 4: regular users.
An overall  one-way (4 cannabis use groups) MANOVA conducted on the outcome variables digit-symbol scores, and SPSES scores, with  depression scores and IQ scores as covariates) revealed no significant main effects, significant interactions or any significant covariates. Subsequent Spearman’s Rank-Order coefficient, however, indicated significant correlations of cannabis use with CUPIT scores, CAST scores, and use of other recreational drugs. Pearson’s correlation coefficient was used for correlation analyses for all other ratio and interval variables. There were no significant Pearson’s correlations found.
Conclusion: The study found no significant association between regular cannabis use and digit-symbol performance; nor was there a significant association between cannabis use and sub-psychotic subjective experiences ratings. Therefore, the student-majority sample did not present any significant deficits in cognitive function depending on cannabis use. Cannabis use was also not related to IQ scores or depression scores; and absence thereof.

text: Examining the Association between Cannabis Use and Working Memory, Processing Speed, and Sub-Psychotic Subjective Experiences New Zealand has among the top two highest prevalence of cannabis use in the world. Additionally, the strings of cannabis on offer in the market of New Zealand is among the most potent ones available. With these two factors at play within New Zealand society, it is important to know the effects of cannabis on mental health. Studies have suggested that regular/heavy use of cannabis can lead to psychosis, however other studies have presented findings contrary to this. Studies consistently found that individuals with psychosis performed much poorer on working memory measure via the digit-symbol subset of the WAIS. Thus this study aimed to investigate how cannabis use may relate with performance of digit-symbol performance and sub-clinical psychotic experiences.
Method: A quantitative design was used to investigate relationships:  between cannabis use, digit-symbol performance, and ratings of the Sub-Psychotic Subjective Experiences Scale (SPSES). Fifty one voluntary random sample participants (n=51) were included in the results of the study. 69% were aged 18-24 years, 84% of the sample population were students, and majority Europeans. Males and females were equally represented. The research sessions were conducted in an office-type laboratory environment. The first part entailed participants completing Wechsler Abbreviated Scale of Intelligence 2nd edition (WASI-II), and Wechsler Adult Intelligence Scale 3rd edition (WAIS-III) digit-symbol subtest with the researcher on a desk. Participants then moved to the computer to complete the questionnaires on background and history, cannabis use (Cannabis Use Problem Identification Test (CUPIT) and Cannabis Abuse Screening Test (CAST) questionnaires for cannabis users), and the Sub-Psychotic Subjective Experiences (SPSES) questionnaire.
Results: Participants were apportioned into four cannabis use groups using self-rating measures obtained from CUPIT and CAST scores. The user groups were 1: non-users, 2: previous uses, 3: non-regular users, and 4: regular users.
An overall  one-way (4 cannabis use groups) MANOVA conducted on the outcome variables digit-symbol scores, and SPSES scores, with  depression scores and IQ scores as covariates) revealed no significant main effects, significant interactions or any significant covariates. Subsequent Spearman’s Rank-Order coefficient, however, indicated significant correlations of cannabis use with CUPIT scores, CAST scores, and use of other recreational drugs. Pearson’s correlation coefficient was used for correlation analyses for all other ratio and interval variables. There were no significant Pearson’s correlations found.
Conclusion: The study found no significant association between regular cannabis use and digit-symbol performance; nor was there a significant association between cannabis use and sub-psychotic subjective experiences ratings. Therefore, the student-majority sample did not present any significant deficits in cognitive function depending on cannabis use. Cannabis use was also not related to IQ scores or depression scores; and absence thereof.

year: 2017

title: Idioms for µ-charts

authors: Anderson, Grant

abstract: This paper presents an idiomatic construct for µ-charts which reflects the high-level specification construct of synchronization between activities. This, amongst others, has emerged as a common and useful idea during our use of µ-charts to design and specify commonly-occurring reactive systems. The purpose of this example, apart from any inherent interest in being able to use synchronization in a specification, is to show how the very simple language of µ-charts can used as a basis for a more expressive language built by definitional extension.

text: Idioms for µ-charts This paper presents an idiomatic construct for µ-charts which reflects the high-level specification construct of synchronization between activities. This, amongst others, has emerged as a common and useful idea during our use of µ-charts to design and specify commonly-occurring reactive systems. The purpose of this example, apart from any inherent interest in being able to use synchronization in a specification, is to show how the very simple language of µ-charts can used as a basis for a more expressive language built by definitional extension.

year: 2001-08-01

title: The rhetorical organization of discourse: language revitalisation and the question of authenticity

authors: Crombie, Winifred

subjects: Te reo Māori

abstract: We propose here one approach to unravelling some aspects of authentic discourse construction in a way that may prove useful to teachers and learners of Māori. The approach is illustrated in relation to one text which realises the argument genre in Māori. In terms of text-type, the example provided is an open letter of advice/warning. The approach illustrated here, and the hypotheses emerging from it, are currently being further tested by one of the authors with reference to a corpus of written texts.

text: The rhetorical organization of discourse: language revitalisation and the question of authenticity We propose here one approach to unravelling some aspects of authentic discourse construction in a way that may prove useful to teachers and learners of Māori. The approach is illustrated in relation to one text which realises the argument genre in Māori. In terms of text-type, the example provided is an open letter of advice/warning. The approach illustrated here, and the hypotheses emerging from it, are currently being further tested by one of the authors with reference to a corpus of written texts.

year: 2000-11-24