The overall aim of the proposed study is to provide generalizable estimates of the incidence/prevalence of long-term chronic use of marijuana and a wide variety of consequences thought to be associated with chronic marijuana use. The specific aims are to: (1) measure lifetime exposure to marijuana and other drugs; (2) measure a wide variety of consequences associated with and perhaps caused by marijuana use; (3) untangle the causal nexus such that the relative, interactive, and independent influence of marijuana use on these consequences can be estimated; and (4) to generalize the results to a known universe of persons at risk. This will be accomplished through 10 year follow-up interviews with a nationally representative sample of men (initial sample = 2,981; a total of 2,510 were interviewed at time 1) born in the eleven birth cohorts (1944-54) and a parallel sample of men born in those years who grew up in high drug use areas of Manhattan (n=294). These men were first interviewed in 1974-75 when they were 20 to 30 years old. At reinterview in the proposed study they will be 30 to 40 years old. An exploratory follow-up sutdy of 445 men from the nationwide sample was conducted in 1982 and was designed to refine measures of a variety of consequences of chronic marijuana use (e.g., pulmonary distress, cardiovascular distress, depression, self-esteem, sense of mastery, functioning in social roles, involvement in crime and drug selling, turning on other persons to drugs, accidents and general health, employment and unemployment, to mention just a few) and to begin to assess their relationship to long-term chronic use of marijuana.