Today I went to have an EEG on a couple different parts of my brain and I am going to start doing neurofeedback, which basically monitors your brain waves in realtime and reports positive changes visually and through sound, so that your brain can begin to change how active/inactive it is.
When I told the EEG practitioner that I smoked marijuana daily and that I'm a medical marijuana patient, she immediately began referring to the pot as "the drugs" and telling me the EEG readout won't be correct until I "stop doing drugs". (yes, I know it's technically a drug, but she was making me feel like a crackhead)
I became slightly skeptical and asked her if the fact it's psychoactive for approximately 2 hours doesn't mean that if I didn't smoke the day of the neurofeedback/EEG it wouldn't report accurate brain activity. She didn't answer me, I thought it was clear she didn't know the answer, and vaguely reminded me that marijuana has a long half-life.
Even more skeptical now, I asked if this meant any anti-depressants or other psychoactive medication should be discontinued and she said absolutely not. Why should one psychoactive drug interfere when others do not?
Also perhaps of some importance to someone, the EEG showed that my frontal lobe was approximately 2.5 times more active than it should be, whereas my right temporal lobe was very inactive, nearly only a quarter of the activity it should be showing. I'm pretty sure I've been this way my entire life and this has nothing to do with cannabis, but I thought I'd get some second opinions. :]