Psychosis can be induced by drugs or can be "drug assisted". Some stimulating drugs, like amphetamines, can cause psychosis, while other drugs, including marijuana, can trigger the onset of psychosis in someone who is already at increased risk because they have "vulnerability".
<a href="http://www.reachoutpsychosis.com/?p=56"><img hspace="5" align="left" class="size-full wp-image-230" title="Reaching Out Classroom Video" src="http://www.reachoutpsychosis.com/wp-content/uploads/2008/09/reachingout_222.jpg" alt="" width="222" height="167" /></a>This video tells the story of Todd, a young man becoming ill with psychosis, and his friend who figures out what's wrong and helps him get help.
"When my sister got sick she was acting really bizarre and the police had to take her to emergency. It was really scary. My friends didn't understand at first that it was just because her brain was sick, but they do now."