Marijuana increases the risk of chronic cough, bronchitis, increases risk of schizophrenia in vulnerable individuals. May increase risk of anxiety, depression and a series of attitude and personality changes, known as “amotivational syndrome.” This syndrome is characterized by a diminished ability to carry out long-term plans, a sense of apathy, decreased attention to appearance and behavior, and decreased ability to concentrate for long periods of time. These changes can also include poor performance in school. Marijuana, just like any other drug, can lead to addiction. It affects the brain’s reward system in the same way as all other drugs of addiction – and the likelihood of addiction increases considerably for those who start young.