Biomedical subjects

Sheree Cairney

Publications and source records attributed to Sheree Cairney.

9 recordsLinked to original sources

PubMed2006

Changes in cannabis use and its consequences over 3 years in a remote indigenous population in northern Australia.

BACKGROUND: Few studies describe cannabis use in indigenous populations, and no longitudinal studies are available in Australia. We conducted 3-year follow-up interviews and assessments in Aboriginal communities in Arnhem Land (Northern Territory, NT). METHODS: A randomly selected sample (n = 161; 80 males, 81 females aged 13-36 years) was assessed in October 2001 and then reassessed in September 2004. An opportunistically recruited sample (n = 104; 53 males, 51 females aged 13-36 years) was also interviewed in 2001 and followed-up in 2004. Cannabis and other substance use were determined by combining proxy assessments by local Aboriginal health workers, medical records and data from interviews. Changes in cannabis use and symptoms of misuse were assessed using McNemar's test for paired proportions and the Wilcoxon signed rank test. Logistic regression assessed associations between clinical presentations and cannabis use at both time-points. RESULTS: Those who used cannabis at both baseline and follow-up were at greater risk than those who never used it to have suffered: auditory hallucinations; suicidal ideation; and imprisonment. In the randomly selected cohort there were fewer cannabis users at follow-up than at baseline (P = 0.003). The reduction was evident in females generally (P = 0.008) and older males (aged = 16 at baseline) (P = 0.007). In those interviewed at both baseline and follow-up we measured no statistically significant reduction in frequency and levels of use, although fewer cannabis users reported symptoms of misuse such as: fragmented thought processes; memory disruption; difficulties controlling use; and auditory and visual hallucinations. CONCLUSIONS: Modest reductions in cannabis use and its consequences in this population were demonstrated. These may be the result of enhanced supply control and broader socio-political changes.

Adolescent↗

PubMed2005

Neurological and cognitive recovery following abstinence from petrol sniffing.

Anecdotal observations suggest that neurological impairments associated with petrol (gasoline) sniffing resolve with abstinence, although these effects have not been proven empirically. Severe exposure to leaded petrol may induce a lead encephalopathy that extends beyond any acute intoxication and requires emergency hospital treatment. Previously, in chronic petrol sniffers, we showed neurological, saccadic, and cognitive abnormalities that were more severe in petrol sniffers with a history of hospitalization for lead encephalopathy, and that correlated with blood lead levels and the length of time of sniffing petrol. Ex-petrol sniffers showed a qualitatively similar but quantitatively less severe pattern of impairment. Petrol sniffing was stopped completely in one of the study communities by modifying social, occupational, and recreational opportunities. After 2 years, we obtained biochemical and neurobehavioral (neurological, saccade, and cognitive) data from all available participants of the earlier study including 10 nonsniffers and 29 chronic petrol sniffers, with six of these individuals previously receiving hospital treatment for lead encephalopathy. Here, we report that blood lead was reduced and that neurobehavioral impairments improved, and in many cases normalized completely. The most severe petrol-related neurobehavioral impairment was observed among individuals who had longer histories of abuse and higher blood lead levels, and among petrol sniffers with a history of lead encephalopathy. Those with the greatest extent of neurobehavioral impairment showed the greatest degree of improvement with abstinence, but were less likely to recover completely. This is the first direct evidence that neurological and cognitive impairment from chronic petrol sniffing ameliorates with abstinence and may recover completely.

Adolescent↗

PubMed2005

Adverse mental health effects of cannabis use in two indigenous communities in Arnhem Land, Northern Territory, Australia: exploratory study.

OBJECTIVE: We investigated adverse mental health effects and their associations with levels of cannabis use among indigenous Australian cannabis users in remote communities in the Northern Territory. METHOD: Local indigenous health workers and key informants assisted in developing 28 criteria describing mental health symptoms. Five symptom clusters were identified using cluster analysis of data compiled from interviews with 103 cannabis users. Agreement was assessed (method comparison approach, kappa-statistic) with a clinician's classification of the 28 criteria into five groups labelled: 'anxiety', 'dependency', 'mood', 'vegetative' and 'psychosis'. Participants were described as showing 'anxiety', 'dependency' etc., if they reported half or more of the symptoms comprising the cluster. Associations between participants' self-reported cannabis use and each symptom cluster were assessed (logistic regression adjusting for age, sex, other substance use). RESULTS: Agreement between two classifications of 28 criteria into five groups was 'moderate' (64%, kappa = 0.55, p < 0.001). When five clusters were combined into three, 'anxiety-dependency', 'mood-vegetative' and 'psychosis', agreement rose to 71% (kappa = 0.56, p < 0.001). 'Anxiety-dependency' was positively associated with number of 'cones' usually smoked per week and this remained significant when adjusted for confounders (p = 0.020) and tended to remain significant in those who had never sniffed petrol (p = 0.052). Users of more than five cones per week were more likely to display 'anxiety-dependency' symptoms than those who used one cone per week (OR = 15.8, 1.8-141.2, p = 0.013). A crude association between the 'mood-vegetative' symptom cluster and number of cones usually smoked per week (p = 0.014) also remained statistically significant when adjusted for confounders (p = 0.012) but was modified by interactions with petrol sniffing (p = 0.116) and alcohol use (p = 0.276). There were no associations between cannabis use and 'psychosis'. CONCLUSIONS: Risks for 'anxiety-dependency' symptoms in cannabis users increased as their level of use increased. Other plausible mental health effects of cannabis in this population of comparatively new users were probably masked by alcohol use and a history of petrol sniffing.

Adolescent↗

PubMed2004

Neurological and cognitive impairment associated with leaded gasoline encephalopathy.

BACKGROUND: A toxic encephalopathy (or 'lead encephalopathy') may arise from leaded gasoline abuse that is characterised by tremor, hallucinations, nystagmus, ataxia, seizures and death. This syndrome requires emergency and intensive hospital treatment. METHODS: We compared neurological and cognitive function between chronic gasoline abusers with (n=15) and without (n=15) a history of leaded gasoline encephalopathy, and with controls who had never abused gasoline (n=15). RESULTS: Both groups of chronic gasoline abusers had abused gasoline for the same length of time and compared to controls, showed equivalently elevated blood lead levels and cognitive abnormalities in the areas of visuo-spatial attention, recognition memory and paired associate learning. However, where gasoline abusers with no history of leaded gasoline encephalopathy showed only mild movement abnormalities, gasoline abusers with a history of leaded gasoline encephalopathy showed severe neurological impairment that manifest as higher rates of gait ataxia, abnormal rapid finger tapping, finger to nose movements, dysdiadochokinesia and heel to knee movements, increased deep tendon reflexes and presence of a palmomental reflex. CONCLUSIONS: While neurological and cognitive functions are disrupted by chronic gasoline abuse, leaded gasoline encephalopathy is associated with additional and long-lasting damage to cortical and cerebellar functions.

Administration, Inhalation↗

PubMed2004

Emerging patterns of cannabis and other substance use in Aboriginal communities in Arnhem Land, Northern Territory: a study of two communities.

A recent rise in cannabis use in Indigenous communities in northern Australia may have compounded existing patterns of other substance use. This paper describes these patterns in Arnhem Land in the 'Top End' of the Northern Territory (NT). Economic impacts of the cannabis trade are also described. In a descriptive cross-sectional study, random samples included 336 people (169 males, 167 females) aged 13 - 36 years. Consensus classification of lifetime and current use of cannabis, alcohol, tobacco, kava, inhalants (petrol) and other drugs was derived based on health workers' proxy assessments. A sample (n = 180, aged 13 - 36) was recruited opportunistically for interview. Lifetime cannabis users among those interviewed (n = 131, 81 males, 50 females) described their current cannabis use, usual quantities purchased and consumed, frequency and duration of cannabis use and other substance use. In the random samples, 69% (63 - 75%) of males and 26% (20 - 31%) of females were lifetime cannabis users (OR = 7.4, 4.5 - 12.1, p < 0.001). The proportion of males currently using cannabis was 67% (60 - 73%) while the proportion of females currently using cannabis was 22% (16 - 27%) (OR = 7.9, 4.8 - 13.1, p < 0.001). Current cannabis users were more likely than non-users to be also using alcohol (OR = 10.4, 4.7 - 23.3, p < 0.001), tobacco (OR = 19.0, 7.9 - 45.8, p < 0.001) and to have sniffed petrol (OR = 9.1, 4.6 - 18.0, p < 0.001) but were less likely to be using kava (OR = 0.4, 0.2 - 0.9, p < 0.001). Among those interviewed, higher tobacco consumption in current users and greater alcohol use in lifetime users was associated with increased cannabis use. Action is required to reduce cannabis use, especially in combination with other substances.

Adolescent↗

PubMed2003

Saccade and cognitive impairment associated with kava intoxication.

Kava is an extract from the Piper methysticum Forst. f. plant that has social and spiritual importance in Pacific islands societies. Herbal remedies that contain kava are used for the psychiatric treatment of anxiety and insomnia. Laboratory studies have found only subtle, if any, changes on cognitive or motor functions from the acute effects of consuming small clinical doses of kava products. Intoxication from recreational doses of kava has not been studied. The performance of individuals intoxicated from drinking kava (n=11) was compared with a control group (n=17) using saccade and cognitive tests. On average, intoxicated individuals had consumed 205 g of kava powder each (approximately 150 times clinical doses) in a group session that went for 14.4 h and ended 8 h prior to testing. Intoxicated kava drinkers showed ataxia, tremors, sedation, blepharospasm and elevated liver enzymes (GGT and ALP), together with saccadic dysmetria, saccadic slowing and reduced accuracy performing a visual search task that only became evident as the task complexity increased. Kava intoxication is characterized by specific abnormalities of movement coordination and visual attention but normal performance of complex cognitive functions. Saccade abnormalities suggest disruption of cerebellar and GABAergic functions.

Adult↗

PubMed2003

Saccade and cognitive function in chronic kava users.

Kava is an extract from the Piper methysticum Forst. f. plant that has been consumed in the Pacific islands for millennia and more recently, among indigenous populations, in northern Australia and throughout the Western world as an herbal medicine. Through alterations on neuronal excitation, kava induces muscle relaxation, anasthesia, and has anxiolytic properties. There have been several isolated reports of psychotic syndromes, severe choreoathetosis and possible seizures following kava use. However, there is no conclusive evidence that kava interferes with normal cognitive processes. We tested a group of current, ex, and nonkava users among an indigenous population in northern Australia, using saccade and cognitive tests that have proven cross-cultural validity and are sensitive to subtle disruptions of the brain arising from substance abuse or neuropsychiatric illness. Despite collecting data from among the heaviest reported kava drinkers in the world, we found no impairment in cognitive or saccade function in individuals who were currently heavy kava users (and had been for up to 18 years), nor was there any impairment in individuals who had been heavy kava users in the past but had abstained for longer than 6 months. Current and ex-kava users showed a higher rate of kava dermopathy, lower body mass index, lowered blood lymphocytes and, in addition, current kava users showed elevated liver enzymes. While there has recently been increasing concern about potentially fatal liver damage attributed to kava use, we have found no evidence of brain dysfunction in heavy and long-term kava users.

Adolescent↗

PubMed2002

The neurobehavioural consequences of petrol (gasoline) sniffing.

This review will introduce petrol (gasoline) sniffing as a specific form of substance abuse. Petrol sniffing is associated with dysfunctions that range in severity from subtle cognitive impairment to encephalopathy and death, and these are discussed with respect to their specific neurological and cognitive bases. Morbidity and mortality rates will also be presented that suggest severe central nervous system damage occurs as a result of petrol sniffing. The neuropharmacological actions of tetraethyl lead and volatile hydrocarbons, the components within petrol, and their contributions to the effects of sniffing petrol are investigated. Reports of human occupational or recreational exposure to either lead additives or volatile hydrocarbons (i.e. inhalants) have provided evidence of the neurological and cognitive effects that may also occur with petrol sniffing. Petrol sniffing causes a progressive decline of cognitive function that eventually leads to permanent neurological changes.

Animals↗

PubMed2002

The neurobehavioural effects of kava.

OBJECTIVE: This review considers the context in which kava is used, together with its underlying psychopharmacological mechanisms, to investigate the neurobehavioural effects associated with kava use. METHOD: We conducted a systematic search using the computerized databases MEDLINE, OVID and PsychLIT for all articles containing any of the following words: kava, kavain, kawa and Piper methysticum. In the opinion of the authors, all articles from this collection containing data that could inform the neurological and cognitive sequelae of kava use were included for the purpose of this review. RESULTS: The use of kava occurs among indigenous populations in the South Pacific and in northern Australia, while also being used throughout the western world as a herbal medicine. Animal studies show that kava lactones alter neuronal excitation through direct interactions with voltage-dependent ion channels, giving rise to kava's muscle relaxant, anaesthetic, anxiolytic and anticonvulsive properties. Several isolated cases of psychotic and severe dystonic reactions following kava use suggest that kava also has psychoactive properties, yet there is no conclusive evidence that kava interferes with normal cognitive processes. CONCLUSIONS: Kava is effective in the treatment of tension and anxiety. There may be risk-factors for severe motor and psychiatric responses to kava use, although these are not well-understood. Given the increasingly widespread use of kava, further investigation is necessary to gain an understanding of its immediate neuropsychiatric effects and long-term cognitive effects.

Adult↗