Sven Andréasson

CANNABIS AND SCHIZOPHRENIA A Longitudinal Study of Swedish Conscripts

The association between level of cannabis consumption and development of schizophrenia during a 15-year follow-up was studied in a cohort of 45,570 Swedish conscripts. The relative risk for schizophrenia among high consumers of cannabis (use on more than fifty occasions) was 6.0 (95% confidence interval 4.0-8.9) compared with non-users. Persistence of the association after allowance for other psychiatric illness and social background indicated that cannabis is an independent risk factor for schizophrenia.

Self reported cannabis use as a risk factor for schizophrenia in Swedish conscripts of 1969: historical cohort study

Abstract Objectives: An association between use of cannabis in adolescence and subsequent risk of schizophrenia was previously reported in a follow up of Swedish conscripts. Arguments were raised that this association may be due to use of drugs other than cannabis and that personality traits may have confounded results. We performed a further analysis of this cohort to address these uncertainties while extending the follow up period to identify additional cases. Design: Historical cohort study. Setting: 1969-70 survey of Swedish conscripts (>97% of the countrys male population aged 18-20). Participants: 50 087 subjects: data were available on self reported use of cannabis and other drugs, and on several social and psychological characteristics. Main outcome measures: Admissions to hospital for ICD-8/9 schizophrenia and other psychoses, as determined by record linkage. Results:Cannabis was associated with an increased risk of developing schizophrenia in a dose dependent fashion both for subjects who had ever used cannabis (adjusted odds ratio for linear trend of increasing frequency 1.2, 95% confidence interval 1.1 to 1.4, P<0.001), and for subjects who had used only cannabis and no other drugs (adjusted odds ratio for linear trend 1.3, 1.1 to 1.5, P<0.015). The adjusted odds ratio for using cannabis >50 times was 6.7 (2.1 to 21.7) in the cannabis only group. Similar results were obtained when analysis was restricted to subjects developing schizophrenia after five years after conscription, to exclude prodromal cases. Conclusions: Cannabis use is associated with an increased risk of developing schizophrenia, consistent with a causal relation. This association is not explained by use of other psychoactive drugs or personality traits relating to social integration. What is already known about this topic Use of cannabis has been associated with an increased risk of developing schizophrenia Alternative explanations for this association include confounding by personality or by use of other drugs such as amphetamines, and use of cannabis as a form of self medication secondary to the disorder What this study adds Self reported cannabis use is associated with an increased risk of subsequently developing schizophrenia, consistent with a causal relation This association is not explained by sociability personality traits, or by use of amphetamines or other drugs Self medication with cannabis is an unlikely explanation for the association observed

Alcohol and mortality among young men: longitudinal study of Swedish conscripts

The association between alcohol consumption and 15 year mortality was studied in a cohort of 49 464 Swedish conscripts, mostly aged 18-19. A strong association was found. The relative risk of death among conscripts with a high consumption of alcohol (>250 g/week) was 3.0 (95% confidence interval (2.3 to 4.1) compared with those with moderate consumption (1-100 g/week). After adjustment for social background variables the relative risk was reduced to 2.1 (95% confidence interval 1.4 to 3.2). Among causes of death a strong predominance was found for violent death, suicide or probable suicide being the leading single cause and accounting for 236 (36%) of all deaths. The reported U shaped curve for total mortality was not confirmed, though when violent deaths were excluded a U shaped curve was suggested for other causes of death. These findings provide important epidemiological data on the drinking habits of young people and the consequences for mortality.

Schizophrenia in users and nonusers of cannabis. A longitudinal study in Stockholm County.

ABSTRACT– In a previous longitudinal study of Swedish conscripts we have shown strong association between level of cannabis consumption at conscription and development of schizophrenia during 15 years of follow‐up. In this study we further analysed data from a subsample of the national cohort. Case records for all conscripts residing in Stockholm County who reported consuming cannabis on more than 10 occasions and who subseqently developed schizophrenia (n= 8) were compared with case records of a sample of conscripts who also developed schizophrenia but reported no cannabis consumption at conscription (n= 13). The relative risk of schizophrenia among cannabis users in Stockholm Country was 4.1 (95% confidence interval 1.8–9.3) compared with nonusers. No evidence was found of a significant role for any other narcotic drug in the emergence of schizophrenia among cannabis abusers. Further, there was no evidence of mental disorder prior to cannabis abuse, even if the role of personality traits could not be fully assessed. A different pattern of mental deterioration was found among cannabis users, with a more abrupt onset of schizophrenic symptoms than nonusers. There was no major difference between users and nonusers in heredity for schizophrenia or other mental disorder. Negative social background factors were more common among cannabis abusers. Although the number of cases in this study was small, the findings support the hypothesis that cannabis does play an aetiological role in schizophrenia.

Treatment of alcohol abuse: an evidence-based review.

This article represents the proceedings of a symposium at the 2002 annual meeting of the Research Society on Alcoholism in San Francisco, CA, organized and cochaired by Mats Berglund and Sten Thelander. The presentations were (1) Preventive interventions against hazardous consumption of alcohol, by Mikko Salaspuro; (2) Treatment of alcohol withdrawal, by Johan Franck; (3) Psychosocial treatment for alcohol problems, by Sven Andréasson and Agneta Ojehagen; and (4) Pharmacological treatment of alcohol dependence, by Mats Berglund.

Cannabis, schizophrenia and other non-affective psychoses: 35 years of follow-up of a population-based cohort.

BACKGROUND There is now strong evidence that cannabis use increases the risk of psychoses including schizophrenia, but the relationship between cannabis and different psychotic disorders, as well as the mechanisms, are poorly known. We aimed to assess types of psychotic outcomes after use of cannabis in adolescence and variation in risk over time. METHOD A cohort of 50 087 military conscripts with data on cannabis use in late adolescence was followed up during 35 years with regard to in-patient care for psychotic diagnoses. RESULTS Odds ratios for psychotic outcomes among frequent cannabis users compared with non-users were 3.7 [95% confidence interval (CI) 2.3-5.8] for schizophrenia, 2.2 (95% CI 1.0-4.7) for brief psychosis and 2.0 (95% CI 0.8-4.7) for other non-affective psychoses. Risk of schizophrenia declined over the decades in moderate users but much less so in frequent users. The presence of a brief psychosis did not increase risk of later schizophrenia more in cannabis users compared with non-users. CONCLUSIONS Our results confirm an increased risk of schizophrenia in a long-term perspective, although the risk declined over time in moderate users.

Mortality and causes of death among homeless women and men in Stockholm

Aim: To study the mortality and causes of death among homeless men and women in relation to the risk indicators, previous treatment for alcohol and drug abuse, previous treatment for mental disorders and non-Swedish citizenship. Methods: The mortality was studied in a cohort comprising 1,757 men and 526 women compared with the general population and persons with inpatient treatment for alcohol- and drug-related disorders. The follow-up period was from 1995 to 1997 until the end of 2005. The causes of death were analyzed. Results: 421 deaths occurred during the follow-up period. The relative risk of death was 3.1, with no difference in mortality between homeless men and homeless women. Previous treatment for alcohol and drug abuse disorders was related to excess mortality and previous treatment for mental disease to lower mortality. Homeless people with inpatient treatment for alcohol or drug use disorders had no higher mortality than the general population in Stockholm with a similar history. There was a dominance of alcohol- and drug-related causes of death. Discussion: Compared with previous studies of homeless people in Stockholm the excess mortality among men found in this study is of the same magnitude. Mortality among women is lower. The mortality rate in homeless people with previous treatment for an alcohol and illicit drug use disorder did not differ from those treated for these disorders in the general population. Conclusions: The most important finding is that excess mortality among homeless men and women in Stockholm is entirely related to alcohol and drug abuse.

Has the leaning tower of presumed health benefits from 'moderate' alcohol use finally collapsed?

The evolving epidemiological literature, including improved methodology for assessing causality in observational studies, is raising doubts about whether moderate alcohol consumption has a protective effect on health.

Drinking less but greater harm: could polarized drinking habits explain the divergence between alcohol consumption and harms among youth?

AIMS This paper describes changes in alcohol consumption among Swedish youth over the past decade with the aim of exploring the polarization hypothesis, which asserts that while a majority of young drinkers have reduced their alcohol consumption, a subgroup have increased their drinking substantially, resulting in greater harm. METHODS We analysed repeated cross-sectional self-report data from 45,841 15-16-year olds and 40,889 18-19-year-old high-school students living in the Stockholm municipality between 2000 and 2010. The questionnaire assessed alcohol and drug use, and risk factors for alcohol misuse. Changes over time at different levels of consumption are presented by age and gender. RESULTS We find evidence of a polarization effect in youth drinking, with consumption reducing significantly over the past 10 years among all young people, except the heaviest drinkers, where consumption and binge drinking tended to increase. The dispersion in per capita consumption also increased over time, indicating more heavy drinkers. The total number of risk factors for alcohol misuse decreased among most survey participants from 2000 to 2010, but with variability between years. CONCLUSION Polarized drinking habits are a likely explanation for the recent divergence between per capita alcohol consumption, which has decreased, and alcohol-related hospitalizations, which have increased sharply among Swedish youth in recent years. We suggest that ongoing social changes could be affecting young people in the form of greater disparities, which are associated with a higher incidence of social problems generally, including heavy drinking.

Alcohol Consumption, Dependence, and Treatment Barriers: Perceptions Among Nontreatment Seekers with Alcohol Dependence

Background: Alcohol use disorders are highly prevalent worldwide. However, only a minority with alcohol dependence seek and undergo treatment. From a public health perspective, it is important to understand why people do not seek treatment. Objectives: This study aims to describe how people with alcohol dependence perceive and discuss treatment for alcohol use disorders and their reasons for seeking and not seeking treatment. Methods: 32 alcohol dependent adults from the general population participated in focus groups and individual interviews in Stockholm during 2011–2012. Data were analyzed with thematic content analysis. Results: Suffering from alcohol dependence, as well as realizing the need for, and entering treatment, were associated with shame and stigma, and were strong barriers to treatment. Other barriers included the desire to deal with alcohol problems on ones own and the view that seeking treatment required total abstinence. Negative health-effects were mainly a nonissue. The participants’ knowledge about treatment options was limited to lifelong abstinence, medication with Disulfiram and residential treatment. These were seen as unappealing and contrasted sharply with preferred treatment. Conclusions/Importance: Public health literacy regarding alcohol use, dependence, and treatment ought to be improved in order to lower barriers to treatment. Treatment services need to better match the needs and wishes of potential service users, as well as taking stigmatization into account. In order to develop suitable treatments, and to reach the majority who do not seek treatment, the clinical understanding of alcohol dependence needs to be expanded to include mild to moderate dependence.