Are the Cochrane group registers comprehensive? A case study of Japanese psychiatry trials

BACKGROUND: Language bias is a form of publication bias and constitutes a serious threat to meta-analyses. The Cochrane Controlled Trials Register is one attempt to remedy this and now contains more than 300,000 citations. However we are still unsure if it provides comprehensive coverage, particularly for non-English trials. METHODS: We have recently established a comprehensive register of Japanese trials of psychotropic drugs through extensive personal contacts, electronic searches and handsearches. We examined two Cochrane psychiatry group registers against this Japanese database. RESULTS: The Japanese register contained 56 reports of randomized controlled trials (RCTs) of antidepressants for depression but the Cochrane Depression, Anxiety and Neurosis group register contained 18, with an overlap of only nine. The Japanese register contained 61 reports of RCTs of neuroleptics for schizophrenia and the Cochrane Schizophrenia group register contained 36, with an overlap of only six. Taking account of some duplicate publications, only a quarter to a third of all relevant Japanese RCTs were retrievable from the Cochrane group registers. CONCLUSIONS: Similar, or worse, yields may be expected with RCTs conducted in other East Asian countries, and in other fields of medicine. What evidence there is suggests that this situation may lead to a systematic over estimate of treatment effect

Uso de álcool, tabaco e outras drogas por adolescentes escolares em município do Sul do Brasil Alcohol, tobacco, and other drug use by teenage students in a city in Southern Brazil

Este trabalho teve como objetivo estudar o comportamento dos estudantes do ensino público municipal de Gravataí, Rio Grande do Sul, Brasil, em relação ao consumo de álcool, tabaco e outras drogas, investigando fatores associados. Foi utilizado delineamento transversal com amostra aleatória representativa de 1.170 escolares da 7ª série e estratificada por região do município. As associações entre desfechos e fatores em estudo foram testadas com regressão de Cox bivariada, modificada para estudos transversais. Foram encontrados, respectivamente, 60,7%, 16,9% e 2,4% de uso na vida de bebida alcoólica, tabaco e outras drogas. Nos últimos trinta dias, o álcool também apresentou a maior prevalência (33%), seguido pelo tabaco (4,4%) e outras drogas (0,6%). O estudo revelou a importância da família e dos amigos na experimentação das substâncias pelos jovens. A prevalência do uso de tabaco e álcool nos últimos trinta dias esteve associada à presença de sentimentos de tristeza, solidão, dificuldade para dormir e ideação suicida. O consumo de outras drogas esteve associado ao sentimento de solidão e ideação suicida.<br>This study analyzes alcohol, tobacco, and other drug use by seventh-graders in municipal schools in the city of Gravataí, Rio Grande do Sul State, Brazil, and associated factors. A cross-sectional school survey was conducted in a representative random sample of 1,170 seventh-graders from municipal schools. The bivariate Cox regression model, modified for cross-sectional studies, was used to evaluate associations between specific factors and outcomes. Prevalence rates for lifetime consumption of alcohol, tobacco, and other drugs were 60.7%, 16.9%, and 2.4%, respectively. Consumption rates in the previous 30 days were: alcohol, 33%; tobacco, 4.4%; and other drugs, 0.6%. The study showed an association with substance use by family and friends. Prevalence of tobacco and alcohol use during the previous 30 days was associated with feelings of sadness, loneliness, insomnia, and suicidal ideation. Use of other drugs was associated with loneliness and suicidal ideation