Too often, I have to figure this out. His parents or teachers sent him to see me because he have had mood swings, verbal explosions and sleep problems. The drug screen comes back positive for cocaine and marijuana, and the garbage can search reveals empty wine bottles. He has a problem with drugs and alcohol. He has mood swings.
Drugs can cause mood swings.
On the other hand, someone with depression or mania may use drugs to take away the pain of uncontrollable mood changes. Figuring out the answer often requires some expert detective work. He need to open up and give me a detailed, honest history. His family members must also be frank about their own drug and psychiatric histories. No more secrets.