• A prospective study to evaluate the change in cognitive function in stimulant users (2023)

    Researcher: Dr Kar Kin Albert CHUNG, the University of Hong Kong


    Background: Cognitive impairments are observed clinically in stimulant abusers, but there was scanty prospective longitudinal research investigating the long-term effects from stimulant abuse on cognitive functions among users themselves.


    Aims: To study the effect of stimulant abuse on cognitive functions in a prospective longitudinal course in relations to different levels of consumption and severities of DSM-5 defined stimulant use disorder (SUD).


    Method: Cognitive functions of stimulant users were assessed by the Montreal Cognitive Assessment (MoCA) and the Frontal Assessment Battery (FAB) three monthly within the 12-month study period. Cognitive changes over time were analyzed with the generalized linear mixed model (GLMM) in addition to the between-group effects of different severities of SUD and controlled demographic variables. Frequency of stimulant use within three months were compared based on severities of SUD to determine whether there were associations to the changes in cognitive functions.


    Results: 84 participants were recruited with the mean MoCA score = 24.99. Eight subjects of all participants at baseline were in the range of DSM-5 defined mild neurodegenerative disorder (MNDD). Although no further significant gross cognitive declines were found for all participants within the 12-month period or being associated to different severities of SUD, six participants remained suffering from MNDD at the end of the study. Female, older users and those with lower education levels tended to score lower in MoCA, while those with longer duration of lifetime stimulant use and active stimulant use as evidenced by positive urine result at the time of the assessment scored lower in FAB. Although frequencies of stimulant use increased with the severities of SUD, no associations were found between the frequency of exposure and the changes in cognitive functions.


    Conclusion: Stimulant abusers who had mild neurodegenerative disorder might not showed prominent gross cognitive declines over time. Several covariates were identified to contribute significant negative impacts to the cognitive functions in stimulant abusers. Future research may consider the dose-effect of stimulants on cognitive changes among users.


  • Cocaine Induced Psychosis: a Literature Review and a Prevalence Study in Local Cocaine Abusers (2022)

    Researcher: Prof. Tang Wai Kwong, The Chinese University of Hong Kong


    Background: Cocaine is the second most commonly abused psychotropic drug in Hong Kong. Cocaine-induced psychosis (CIP) is an important psychiatric disorder in Cocaine users, but the prevalence and risk factors of CIP and other psychiatric disorders in local Cocaine users is unknown.


    Aims: Part I: To ascertain the risk factors, frequency, symptoms, pathomechanism and treatment of cocaine-induced psychosis (CIP)
    Part II: To determine the prevalence of CIP and psychotic symptoms in local Cocaine users. Secondary objectives will include determining the prevalence of mood and anxiety disorders in local Cocaine users.


    Method: Part I: A PubMed search was conducted in April 2018 using the keywords ‘cocaine’ and ‘psychosis’ to identify relevant articles (limits: English language, published between 1966 and 2018, human studies, abstracts available).
    Part II: CIP and other psychiatric disorders were assessed using 40-90 minutes structured clinical interview.


    Results: Part I: Psychotic symptoms are common amongst cocaine users. The prevalence of CIP ranged from 5% to 75% (median 53%). CIP is more common in subjects with older age, trait anxiety, antisocial personality disorder or poly drug use and in subjects with a family history of psychotic disorders. Grey matter deficits have been found in CIP indicated that subcortical pathology may contribute to the development of CIP. It is also possible that CIP is a complex genetic disease, and lowered plasma levels of neurotrophin are important factors in susceptibility to CIP. Short-term anxiolytics (benzodiazepines) or sleep medications may be useful adjunct treatment; long-term treatment of CIP should focus on abstinence from cocaine to prevent future episodes of psychosis.
    Part II: 71% of the subjects developed substance-induced psychotic disorder (CIP), 49% of the subjects developed substance-induced mood disorders, and 30% of the subjected had substance-induced anxiety disorders.


    Conclusion: Part I: Cocaine use commonly results in the development of acute psychosis. The variation in findings between studies is likely to be due to many factors, including not only methodological differences in study design, but also cultural and demographic factors.
    Part II: This study found that CIP was common among local cocaine users and that a longer duration of cocaine use increased the risk of CIP.


  • Adverse Mental Health Effects of a New Psychotropic Substance (Synthetic Cathinones): a Literature Review (2022)

    Researcher: Prof. Tang Wai Kwong, The Chinese University of Hong Kong / Dr. Tang Ka Lam Alan, Prince of Wales Hospital / Dr. Chan Fu, North District Hospital


    Background: Synthetic Cathinones (SC) use can lead to a use disorder (i.e. an addiction) and increase the risk of psychosis and other psychiatric disorders.


    Aims: To identify the risk factors, frequency, symptoms, pathological mechanism, and treatment of synthetic cathinone (SC)-related psychiatric disorders (namely, SC use disorder [SCUD], psychosis, mood disorders, anxiety disorders, and cognitive impairment).


    Method: A Medline search was performed in August 2020, using the keywords ‘synthetic cathinones’ and ‘synthetic cathinone use disorder’ or ‘psychosis’ or ‘depression’ or ‘bipolar’ or ‘anxiety disorders’ or ‘cognition’, to identify relevant articles for data synthesis.


    Results: 14% of SC users have psychosis and 35% have psychotic symptoms. SC can also impairs verbal and spatial memory and verbal fluency. The risk factors and neurobiology of SC-induced psychosis are unknown. The prevalence of mania, depressive disorder, anxiety disorder, and cognitive impairment in SC users is unknown.


    Conclusion: SC use can be addictive, and it increases the risk of psychosis and other psychiatric disorders. Further clinical research is needed on the prevalence, underlying neurobiological factors, clinical course, and treatment of SCUD and its related comorbidities.


  • Ice Induced Psychosis: a Literature Review and a Prevalence Study in Local Ice Abusers (2020)

    Researcher: Prof. Tang Wai Kwong, The Chinese University of Hong Kong


    Background: In recent years, there is a growing trend of ICE use in Hong Kong. However, there has been a lack of study on ICE induced psychosis (IIP) in local users. To identify the prevalence, clinical features, and risk factors of IIP and other psychiatric disorders in local ICE users, we conducted a large-scale study to investigate the prevalence of psychiatric comorbidity in a group of ICE users.


    Aims: (1)To determine the prevalence of IIP and psychotic symptoms in local ICE users. (2) To identify the prevalence of mood and anxiety disorders in local ICE users.


    Method: 260 ICE users as participants were recruited from July 2017 to July 2019. All participants were invited to a 40–90 minute face-to-face structured diagnostic interview for examination of their psychiatric condition. Demographic, clinical, and drug use data were also collected.


    Results: The most prevalent psychotic symptoms were delusion of reference (65%), persecutory delusion (42%), auditory hallucination (59%), visual hallucination (42%), and tactile hallucination (33%). Lifetime substance-induced mood and anxiety disorders were found in 59% and 64% of the participants respectively.


    Conclusion: IIP is very common in local ICE users; one-fifth of the users had persistent psychotic symptoms, included delusions and hallucinations. The amount of ICE consumption and ICE dependence would increase the risk of IIP. Mood and anxiety disorders are common in ICE users as well.


  • Gastrointestinal, hepatic and biliary sequelae of frequent ketamine use: a prospective observational study (2020)

    Researcher: Dr. Seto Wai Kay Walter, The University of Hong Kong

    Background: Recreational ketamine use (i.e. non-prescribed use of ketamine irrespective of the frequency of use) has emerged as an important health and social issue worldwide. Abdominal discomfort and associated gastrointestinal complains are common in frequent ketamine users, and damage to the biliary tract has been previously reported, although the clinical profiles and sequelae have not been well-described.


    Aims: (i) determine the underlying aetiology of abdominal discomfort among frequent ketamine users; and (ii) determine the prevalence of different gastrointestinal, liver and biliary pathologies among frequent ketamine users and to determine risk factors associated with the development of different gastrointestinal, liver and biliary pathologies among frequent ketamine users.


    Method: 127 Chinese individuals who used ketamine recreationally at least twice per month over six months in the past two years were recruited via a territory-wide community network of charitable organisations tackling substance abuse. Clinical demographics were recorded, and gastrointestinal symptoms were assessed via a standardised score. For participants at risk of biliary tract anomalies, magnetic resonance cholangiography (MRC) was performed and interpreted independently by two radiologists, with findings analysed in association with clinical characteristics.


    Results and Conclusion: Severe degrees of abdominal discomfort and biliary anomalies on MRC were noted among recreational ketamine users, with clinical benefit of abstinence clearly demonstrated.


  • Evidence of brain damage in chronic ketamine users – a brain imaging study (2016)

    Researcher: Prof. Tang Wai Kwong, The Chinese University of Hong Kong
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