Dear user, Thank you for writing to Healthcaremagic. I understand your concern. Marijuana (weed) causes sweating, Headaches, restlessness, forgetfulness, Visual distortions (what you described),lack of concentration, morbid suspicious behavior, mood changes, perceptual changes, feeling impersonal, panic disorder, amotivational syndrome, delusions and psychosis . These are suggestive of cannabis intoxication. For the best interest of his well being, I suggest him to discuss with counselor or psychiatrist about weed use. Psychiatrist can improve his motivation to remain free from weed. This will help you both. Wish you good health.