are particularly important when we consider whether to legalize the use of marijuana. 5. Mental functions are impaired by marijuana. Recent research by such scientists as Glen Ruplinger has established that one’s motor coordination, memory, attention, and mental performance are impaired by marijuana. This is evidenced by verbal confusion and the inability to communicate intelligently. 6. When high, a person’s awareness of his self-identity and even of his body may lessen or completely vanish. 7.