Psychological complications include psychosis, paranoia anxiety, violent behavior, and depression that may lead to suicide. Psychological states induced can include paranoia and Psychosis. Misidentification of mushrooms can lead to serious or fatal illness. PCP users often become violent and oblivious to pain, leading to serious injuries to themselves and others. Chronic marijuana smoking results in respiratory difficulties, bronchitis, and probably both emphysema and lung cancer.
Episodic use can cause panic reactions, flashbacks, and depression.
Psychosis may occur in susceptible individuals, and severe toxic reactions may result from ingestion of large quantities. Some of the most serious consequences of marijuana use result when decreased judgment, impaired perceptions and motor functions, and inability to carry out multistep tasks lead to motor vehicle crashes and other trauma.