Sheree Cairney

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.

Psychological and cognitive assessment of Indigenous Australians

Objective: The aim of the present review was to evaluate the psychological and cognitive assessments that have been considered suitable for Indigenous Australians. This will provide a basis from which future developments can occur, leading to improved mental health services for Indigenous Australians. Method: Literature searches of key health science databases were conducted using the following search terms in various combinations: Indigenous, Aboriginal, cognitive, assessment, mental health, social emotional well-being, psychological, Australian. Psychological, mental health or social and emotional well-being assessments as well as cognitive assessments that have been utilized and found suitable in Indigenous Australian populations were reviewed. Results: A limited number of assessments were found and discussed and these varied in their applications. Conclusions: Further research and development is necessary to establish a national approach to assessing or screening mental health and cognitive function among Indigenous Australians. This is an important and necessary step to improve mental health and related services for Indigenous Australians.

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.

Health effects of kava use in an eastern Arnhem Land Aboriginal community

Abstract

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.

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 kavas 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 riskfactors for severe motor and psychiatric responses to kava use, although these are not wellunderstood. 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.

Measuring Exposure to Cannabis use and other Substance use in Remote Aboriginal Populations in Northern Australia: Evaluation of A ‘Community Epidemiology’ Approach using Proxy Respondents

We evaluate a method to describe changing substance use patterns in northern Australias remote Aboriginal communities (Arnhem Land, Northern Territory). Substance use was assessed in random samples in two communities A (n = 194) and B (n = 176). Five Aboriginal health workers made assessments independently of each other in community A. A different group of three health workers made independent assessments in community B. Sub-samples were opportunistically recruited for interview (community A, n = 77; community B, n = 55). In community C, 101 people were interviewed and were also assessed by four local health workers working together. Proportional agreements (kappa-κ statistic) among health workers for a history of substance use and current use, varied from κ = 0.207 for petrol sniffing (P = 0.006) up to κ = 0.749 for cannabis use (P<0.001), all better than would be expected by chance. In communities A and B, agreement between health workers’ consensus and self-reported substance use was weaker (0.103<κ<0.482) probably because of under-reporting in interviews. In community C, where interviews were conducted in a confidential clinic setting, agreement between health workers’ concensus and self-report varied from κ = 0.273 for petrol sniffing (P<0.001) up to 0.819 for tobacco use (P<0.001). Aboriginal health worker consensus classification clarified equivocal self-report data.

Saccade dysfunction associated with chronic petrol sniffing and lead encephalopathy

Background: In chronic petrol sniffers, recent exposure to high levels of leaded petrol may give rise to a lead encephalopathy characterised by tremor, chorea, ataxia, hyperreflexia, convulsive seizures, and death. Neurological abnormalities associated with lead encephalopathy involve the cortex, basal ganglia, cerebellum, and brain stem. Objective: To use saccadic eye movement tasks as an experimental tool to determine which CNS changes are associated with chronic petrol sniffing and which with a history of lead encephalopathy, and to what extent these changes are reversible. Methods: Saccade function was assessed in chronic petrol sniffers with a history of lead encephalopathy (encephalopathic sniffers), chronic petrol sniffers who had never suffered lead encephalopathy (chronic sniffers), individuals who had sniffed petrol in the past but had not done so for more than six months (ex-sniffers), and individuals who had never sniffed petrol (non-sniffers). Results: Chronic sniffers showed increased latency of visually guided saccades and antisaccades and increased antisaccade errors which suggested cortical and basal ganglia dysfunction. These abnormalities returned to normal in ex-sniffers. Encephalopathic sniffers showed the same abnormalities as chronic sniffers but with greater severity and additional saccadic signs including dysmetria, gaze evoked nystagmus, and saccade slowing which usually indicate cerebellar and brain stem dysfunction. Conclusions: Chronic petrol abuse is associated with cortical and basal ganglia abnormalities that are at least partially recoverable with abstinence. Additional long term cerebellar and brain stem abnormalities are associated with lead encephalopathy.

Cognitive recovery during and after treatment for volatile solvent abuse

BACKGROUND Cognitive impairment reflecting CNS disruption in chronic solvent abusers can resolve within two years of abstinence. However, the specific time course for recovery has yet to be determined empirically. This study monitored cognition among solvent (i.e., gasoline) abusers throughout 8 weeks of residential treatment. It also investigated the extent to which solvent-related cognitive impairments persisted following discharge. METHODS Non-drug using healthy controls (n=33) and solvent abusers (n=29) who had inhaled gasoline, regularly or episodically, for an average of 4.3 years (SD=2.7) were assessed. Using linear mixed model analyses, solvent abusers were compared to healthy controls throughout treatment at baseline, two weeks, four weeks and six weeks, on visual motor, attention, learning, memory, and executive function tasks. Ten users who maintained abstinence were reassessed an average of 12 months later (SD=2.8) and were compared to healthy controls (n=12) retested at the same time interval using ANCOVA while controlling for age and baseline performance. RESULTS At baseline, solvent abusers showed cognitive deficits on visual motor, learning and memory, paired associate learning, and executive functions. Paired associate learning performance improved within 6 weeks of abstinence, however, impairments in visual motor speed, learning and memory, and executive function persisted throughout and in some cases beyond treatment. CONCLUSIONS Cognitive deficits exist for solvent abusers upon treatment entry. Some impairments resolve within weeks of abstinence, while memory and executive function improves gradually over months to years of abstinence, and might never fully recover.

Detecting psychological symptoms related to substance use among Indigenous Australians

INTRODUCTION AND AIMS Substance misuse and psychological comorbidities can be common and may impact negatively on treatment outcomes. However, without appropriate tools, detecting psychological symptoms for Indigenous people can be difficult. This study assessed the appropriateness of an eight-item screening tool (based on Strong Souls) for measuring any relationships between substance use and psychiatric symptoms for Indigenous Australians. DESIGN AND METHODS Indigenous Australians attending secondary or tertiary education institutions or substance use rehabilitation facilities in the Northern Territory (n = 407; mean age = 27.82) were assessed for depressive, anxiety and psychotic symptoms. The group represented 45 language groups from 95 urban and remote communities. English comprehension was measured on a scale from 0 (no understanding) to 10 (excellent understanding; M = 7.99, SD = 2.31). Ordinal regression analyses examined any associations between demographic and substance use factors and psychological symptoms. RESULTS Compared with non-users, current cannabis users were significantly more likely [odds ratios (ORs) = 2.2-4.4] to experience depressive or anxiety symptoms. Frequent cannabis users experienced more symptoms than occasional users. Prior-inhalant users were more likely to feel lonely (OR = 2.18) compared with non-inhalant users. Frequent alcohol users were less likely (OR = 0.44) to feel sad than non-users. These results are interpreted with respect to previous research and methodological limitations. DISCUSSION AND CONCLUSIONS Symptoms of depression or anxiety may be common for individuals seeking treatment for substance misuse and with minor improvement, these eight-items may provide a useful screen for psychological symptoms in Indigenous Australians.