Schizophrenia

Any of a group of psychotic disorders usually characterized by withdrawal from reality, illogical patterns of thinking, delusions, and hallucinations, and accompanied in varying degrees by other emotional, behavioural, or intellectual disturbances.

Schizophrenia is associated with dopamine imbalances in the brain and defects of the frontal lobe and is caused by genetic, other biological, and psychosocial factors.

Source: The American Heritage® Dictionary of the English Language, Fourth Edition  

Effects of cannabis