DSM-IV alcohol diagnosis and symptom prevalence data were obtained from five community and four clinical adolescent samples. All of the studies used retrospective self-reports of alcohol-related problems that may be subject to bias. There was a moderate level of cross-study agreement on the relative prevalence of alcohol symptoms. The most common symptoms were dependence criteria -- tolerance and drinking more or longer than intended. These high prevalence symptoms affected the ratio of abuse to dependence diagnoses in some studies, the prevalence of the physiological dependence subtype, and the proportion of subthreshold cases of dependence. The study observed that the conceptual and empirical relationships between DSM-IV alcohol abuse and dependence diagnoses remain controversial. The conceptual work needed to better delineate the content and boundaries of diagnoses of alcohol abuse and dependence depends on future research that focuses on improved measurement of alcohol-related symptoms. Tables, references