Is cannabis use a contributory cause of psychosis?

Objective: To assess whether cannabis use in adolescence and young adulthood is a contributory cause of schizophreniform psychosis in that it may precipitate psychosis in vulnerable individuals. Method: We reviewed longitudinal studies of adolescents and young adults that examined the relations between self-reported cannabis use and the risk of diagnosis with a psychosis or of reporting psychotic symptoms. We also reviewed studies that controlled for potential confounders, such as other forms of drug use and personal characteristics that predict an increased risk of psychosis. We assessed evidence for the biological plausibility of a contributory causal relation. Results: Evidence from 6 longitudinal studies in 5 countries shows that regular cannabis use predicts an increased risk of a schizophrenia diagnosis or of reporting symptoms of psychosis. These relations persisted after controlling for confounding variables, such as personal characteristics and other drug use. The relation did not seem to be a result of cannabis use to self-medicate symptoms of psychosis. A contributory causal relation is biologically plausible because psychotic disorders involve disturbances in the dopamine neurotransmitter systems with which the cannabinoid system interacts, as demonstrated by animal studies and one human provocation study. Conclusion: It is most plausible that cannabis use precipitates schizophrenia in individuals who are vulnerable because of a personal or family history of schizophrenia.

The mental health risks of adolescent cannabis use

Since the early 1970s, when cannabis first began to be widely used [1], the proportion of young people who have used cannabis has steeply increased and the age of first use has declined [2, 3]. Most cannabis users now start in the mid-to-late teens [1], an important period of psychosocial transition when misadventures can have large adverse effects on a young person's life chances.

The epidemiology and genetics of smoking initiation and persistence: Crosscultural comparisons of twin study results

We examined whether there are crosscultural differences in the magnitude of genetic and environmental contributions to risk of becoming a regular smoker and of persistence in smoking in men and women. Standard methods of epidemiologic and genetic analysis were applied to questionnaire data on history of cigarette use obtained from large samples of male and female like-sex twins from three different countries: Australia (N = 2284 pairs), Sweden (N = 8651 pairs), and Finland (N = 10,948 pairs). Samples were subdivided into three age groups (AG), 18-25 years, 26-35 years, and 36-46 years of age. The magnitude of genetic influence for lifetime smoking was found to be consistent across country and AG for women (46%) and men (57%), and estimates of the contribution from environmental influences shared by twin and co-twin could be equated across all countries by AG for the women (from youngest to oldest AG: 45%, 35%, and 26%), but not for men, with separate estimates obtained for the Scandinavian (33%, 29%, and 19%) and the Australian men (26%, 9%, and 11 %). There was no evidence for an important role for shared environmental influences on persistent smoking, and the genetic contribution was found to be consistent in magnitude in men and women, and the same across country and AG (52%). There are strong genetic influences on smoking behavior, and that risk of becoming a smoker (but not persistence in smoking) may be modified by experiences shared by twins that differ by AG and, at least for men, cultural background.

Occupational therapy and evidence-based practice in mental health

Evidence-based practice (EBP) represents a paradigm shift in health care. This review has two aims. The first is to consider the merits of EBP,especially in respect of its use in mental health settings. The second is both to identify psychosocial interventions that have an established evidence base for effectiveness and to provide an analysis of the quality of this evidence and its implications for occupational therapy. Supported employment, family psychoeducation, assertive case management and integrated substance use treatment are examined in detail. It is proposed that occupational therapists working in mental health give priority to psychosocial interventions that are based on evidence and incorporate these into their practice. It is further proposed that, in implementing EBP,practitioners take an active evaluating position in relation to published evidence, paying particular attention to the evidence of effectiveness in equivalent clinical environments.

Defining nicotine dependence for genetic research: evidence from Australian twins

Background. Whether current criteria used to define nicotine dependence are informative for genetic research is an important empirical question. The authors used items of the DSM-IV and of the Heaviness of Smoking Index to characterize the nicotine dependence phenotype and to identify salient symptoms in a genetically informative community sample of Australian young adult female and mate twins. Method. Phenotypic and genetic factor analyses were performed on nine dependence symptoms (the seven DSM-IV substance dependence criteria and the two Heaviness of Smoking Index (HSI) items derived from the Fagerstrom Tolerance Questionnaire, time to first cigarette in the morning and number of cigarettes smoked per day). Phenotypic and genetic analyses were restricted to ever smokers. Results. Phenotypic nicotine dependence symptom covariation was best captured by two factors with a similar pattern of factor loadings for women and men. In genetic factor analysis item covariation was best captured by two genetic but one shared environmental factor for both women and men; however, item factor loadings differed by gender. All nicotine dependence symptoms were substantially heritable, except for the DSM-IV criterion of 'giving up or reducing important activities in order to smoke', which was weakly familial. Conclusions. The salient behavioral indices of nicotine dependence are similar for women and men. DSM-IV criteria of tolerance, withdrawal, and experiencing difficulty quitting and HSI items time to first cigarette in the morning and number of cigarettes smoked per day may represent the most highly heritable symptoms of nicotine dependence for both women and men.

Identifying and predicting adolescent smokers' developmental trajectories

Very few studies have defined trajectories of smoking. In the present study, we modeled growth in adolescent smoking and empirically identified prototypical trajectories. We conceptualized escalation of smoking as a growth process and modeled rates of change and heterogeneity of these patterns using latent growth mixture modeling. The analysis identified six trajectories with low ambiguity about group membership (early rapid escalators, late rapid escalators, late moderate escalators, late slow escalators-smokers, stable puffers, and late slow escalators-puffers). A trajectory of quitters was not identified. We also examined predictors of the smoking trajectories. The predictors were assessed across the adolescent years and included variables related to smoking and other substance use, as well as a range of variables related to sociodemographic factors and mental health. Observed change in the pattern of predictors across age has implications for the mechanism of effect of these variables in relation to smoking trajectories, including predictors that differentiated among daily smokers, variables that may determine the trajectory (e.g., friends smoking), and variables that may result from the trajectory (e.g., marijuana use, less attachment to friends).

Role of culture in gambling and problem gambling

There has been a significant gap in the gambling literature regarding the role of culture in gambling and problem gambling (PG). This paper aims to reduce this gap by presenting a systematic review of the cultural variations in gambling and PG as well as a discussion of the role cultural variables can play in the initiation and maintenance of gambling in order to stimulate further research. The review shows that although studies investigating prevalence rates of gambling and PG among different cultures are not plentiful, evidence does suggest certain cultural groups are more vulnerable to begin gambling and to develop PG. Significant factors including familial/genetic, sociological, and individual factors have been found in the Western gambling literature as playing important roles in the development and maintenance of PG. These factors need to be examined now in other cultural groups so we can better understand the etiological processes involved in PG and design culturally sensitive treatments. In addition, variables, such as cultural values and beliefs, the process of acculturation, and the influence of culturally determined help-seeking behaviors need to be also examined in relation to the role they could play in the initiation of and maintenance of gambling. Understanding the contribution of cultural variables will allow us to devise better prevention and treatment options for PG. Methodological problems in this area of research are highlighted, and suggestions for future research are included. (C) 2004 Elsevier Ltd. All rights reserved.

How common is comorbidity and why does it occur?

Comorbidity is most generally defined as the co-occurrence of two or more mental health problems. Comorbidity between drug and other psychological disorders has emerged as a major clinical, public health and research issue over the past few decades. The reasons for comorbidity are complex. Furthermore, comorbidity is often associated with poor treatment outcome, severe illness course, and high service utilisation. This presents a significant challenge with respect to the identification, prevention and management of people with comorbid disorders. The unmet need for treatment within this group is considerable and the lack of research is unacceptable. This paper will give a brief overview of epidemiological research into comorbidity; and examine the reasons why comorbidity might occur.

The relationship between acute alcohol consumption and consequent injury type

Aims: The aim of this study was to quantify the relationship between acute alcohol consumption and injury type (nature of injury, body region injured), while adjusting for the effect of known confounders (i.e. demographic and situational variables, usual drinking patterns, substance use and risk-taking behaviour). Methods: A cross-sectional study was conducted between October, 2000 and October, 2001 of patients aged >= 15 years presenting to a Queensland Emergency Department for treatment of an injury sustained in the preceding 24 h. There were three measures of acute alcohol consumption: drinking setting, quantity, and beverage type consumed in the 6 h prior to injury. Two variables were used to quantify injury type: nature of injury (fracture/dislocation, superficial, internal, and CNS injury) and body part injured (head/neck, facial, chest, abdominal, external, and extremities). Both were derived from patient medical records. Results: Five hundred and ninety three patients were interviewed. Logistic regression analyses indicated that, after controlling for relevant confounding variables, there was no significant association between any of the three measures of acute alcohol consumption and injury type. Conclusions: The effects of acute alcohol consumption are not specific to injury type. Interventions aimed at reducing the incidence of alcohol-related injury should not be targeted at specific injury types.

Effectiveness of hospital-based smoking cessation

Study objectives: Smoking cessation for current smokers is a health-care imperative. It is not clear which approaches to smoking cessation are the most effective in the hospital setting and which factors predict long-term abstinence. We hypothesized that a hospital-based smoking cessation program involving behavioral modification and support would provide an effective intervention for smoking cessation. Design: Prospective cohort study. Setting: Smoking cessation clinics in a tertiary referral, cardiothoracic hospital. Patients or participants: Two hundred forty-three smokers and 187 never-smoker control subjects. Interventions: Smokers underwent specific sessions of individual counseling on behavioral modification, including written information, advice about quit aids, and support during the quit attempt. Abstinence was confirmed by exhaled carbon monoxide measurements. Measurements and results: Compared to never-smoker control subjects, smokers were more likely to have grown up with a smoking father or siblings, and to currently live or socialize with other smokers. Two hundred sixteen smokers attended at least two sessions of the smoking cessation program. Of these, 25% were unavailable for follow-up at 12 months and were assumed to be smoking. The point prevalence abstinence rate at 12 months was 32%. Independent factors associated with abstinence at 12 months were self-belief in quitting ability, having a heart condition, growing up without siblings who smoked, and increasing number of pack-years. Conclusions: This prospective study has demonstrated that this hospital-based smoking cessation program was as effective as programs in other settings. Social and psychological factors were associated with a greater chance of abstinence.

Portrayal of depression and other mental illnesses in Australian nonfiction media

This study describes Australian media portrayal of mental illnesses, focusing on depression. A random sample of 1,123 items was selected for analysis from a pool of 13,389 nonfictional media items about mental illness collected between March 2000 and February 2001. Depression was portrayed more frequently than other mental illnesses. Items about depression, eating disorders, and substance use disorders most commonly described policies or programs, whereas items about schizophrenia most frequently portrayed individuals or symptoms and treatment. A minority of items about depression presented information about symptoms, causes, treatment, or prognosis. Although such information was generally accurate, a proportion of items conveyed misleading messages. There is therefore scope for increasing the level of accurate information provided about depression in the Australian media. (c) 2005 Wiley Periodicals, Inc.

Family structure and age at menarche: A children-of-twins approach

Girls who grow up in households with an unrelated adult male reach menarche earlier than peers, a finding hypothesized to be an evolutionary strategy for families under stress. The authors tested the alternative hypothesis that nonrandom selection into stepfathering due to shared environmental and/or genetic predispositions creates a spurious relation between stepfathering and early menarche. Using the unique controls for genetic and shared environmental experiences offered by the children-of-twins design, the authors found that cousins discordant for stepfathering did not differ in age of menarche. Moreover, controlling for mother's age of menarche eliminated differences in menarcheal age associated with stepfathering in unrelated girls. These findings strongly suggest selection, and not causation, accounts for the relationship between stepfathering and early menarche.

Acute alcohol consumption and mechanism of injury

Objective: The purpose of this study was to determine whether injury mechanism among injured patients is differentially distributed as a function of acute alcohol consumption (quantity, type, and drinking setting). Method: A cross-sectional study was conducted between October 2000 and October 2001 in the Gold Coast Hospital Emergency Department, Queensland, Australia. Data were collected quarterly over a 12-month period. Every injured patient who presented to the emergency department during the study period for treatment of an injury sustained less than 24 hours prior to presentation was approached for interview. The final sample comprised 593 injured patients (males = 377). Three measures of alcohol consumption in the 6 hours prior to injury were obtained from self-report: quantity, beverage type, and drinking setting. The main outcome measure was mechanism of injury which was categorized into six groups: road traffic crash (RTC), being hit by or against something, fall, cut/piercing, overdose/poisoning, and miscellaneous. Injury intent was also measured (intentional vs unintentional). Results: After controlling for relevant confounding variables, neither quantity nor type of alcohol was significantly associated with injury mechanism. However, drinking setting (i.e., licensed premise) was significantly associated with increased odds of sustaining an intentional versus unintentional injury (odds ratio [OR] = 2.79, 95% confidence interval [CI] = 1.4-5.6); injury through being hit by/against something versus other injury types (OR = 2.59, 95% CI = 1.4-4.9); and reduced odds of sustaining an injury through RTC versus non-RTC (OR = 0.02, 95% CI = 0.004-0.9), compared with not drinking alcohol prior to injury. Conclusions: No previous analytical studies have examined the relationship between injury mechanism and acute alcohol consumption (quantity, type, and setting) across all types of injury and all injury severities while controlling for potentially important confounders (demographic and situational confounders, risk-taking behavior, substance use, and usual drinking patterns). These data suggest that among injured patients, mechanism of injury is not differentially distributed as a function of quantity or type of acute alcohol consumption but may be differentially distributed as a function of drinking setting (i.e., RTC, intentional injury, being hit). Therefore, prevention strategies that focus primarily on the quantity and type of alcohol consumed should be directed generically across injury mechanisms and not limited to particular cause of injury campaigns.

Number and type of substances in alcohol and drug-related completed suicides in an Australian sample

Background: The association between substance use and suicide is well-established, but evidence is scant regarding the relationship between the number, type, and level of substances and other risk factors in completed suicide across the lifespan. Aims: To examine the relationship between social/demographic characteristics and the number, type, and level of drugs present in an unrestricted age sample of completed suicides in Australia. Method: An analysis was undertaken of 893 substance-related suicides using data from the Government Statistician's Office for the years 1989-1992. Results: The number and type of substances present in suicide victims was related to the individual's gender, age, marital status, employment status, and method of suicide. Blood alcohol level was significantly different between the methods of suicide, but was unrelated to demographic characteristics of the individual. The level of antidepressants and minor tranquilizers in the individuals was also unrelated to demographic characteristics. Conclusion: Examination of the type and number of substances present in completed suicides is an important component in creating profiles of potential suicide victims.