Marcus had a miserable life. His father was killed several years ago in a drive-by shooting when Marcus was fifteen Since then, his mother had brought a string of boyfriends home over the years, insisting that he call them "Dad". The latest one had been a real "piece of work". He would come home drunk and beat Marcus' mother. If he finished with her before passing out, he'd start on Marcus next. A year ago, he'd broken Marcus' jaw with a baseball bat and put Marcus mother in the hospital

Not surprisingly Marcus looked for any way to escape that he could. Some kids in the neighborhood had introduced him to a number of different drugs, and he tried them all. His favorite was LSD. He liked watching weird things happen right before his eyes and often thought that he had the power to control what hallucinations he saw. He knew that if he concentrated hard enough he could make them actually happen to his "dad"

During a particularly rough period at home, Marcus stayed on LSD pretty much all day, every day. He started mixing the LSD with other drugs too. One night his "dad" caught Marcus stealing money out of his wallet and threw him down the stairs headfirst.

When Marcus woke up he was in a hospital under restraint. The nurse told him that he'd been babbling for several davs about melting walls and scooping out his "dad's" brains and feeding them to a dog

1 What do you believe to be appropriate diagnoses for Marcus at this time? Consider both substance use and mental health diagnoses, and support your response citing the specific criteria for those diagnoses.

Marcus presents with odd behavior, a recent head injury, recent use of hallucinogens, and high risk factors for a psychotic disorder. What additional information would you want to seek in order to determine the cause of his odd behavior?