A 28-year-old man was brought to the emergency department by his wife, who said he has been “acting strangely.”

A 28-year-old man was brought to the emergency department by his wife, who said he has been “acting strangely.” After losing his job 3 months ago, he devoted 20 hours per day to a new secretive “project” and will no longer let her in the garage. He was diagnosed with depression at 18 years old after a suicide attempt and has been taking sertraline since that time. The patient said he felt great about his new work for a major international conglomerate and an exposé he is writing about a former employer. He looked around the room suspiciously, spoke rapidly, and paced, saying that he suspects his wife may be spying on him for his former boss. Toxicology screening was positive for marijuana. Which of the following is the most likely diagnosis?

A. Bipolar disorder

B. Schizophrenia

C. Cannabis use disorder

D. Adjustment disorder

E. Delusional disorder