It is very common for people who have used street drugs to wonder if the drugs may have caused their symptoms.

Street drugs can cause many symptoms that can be found in mental illnesses, such as hallucinations, feelings of unreality, paranoia, and both extremely high and low moods. Because of this, it can be difficult or impossible to accurately diagnose (or treat) mental illness in someone who is also using street drugs.

However, there is very little evidence to suggest that using street drugs...