Recent quotes:

ADHD drug Ritalin has no effect on primate prefrontal cortex -- ScienceDaily

Julio Martinez-Trujillo and colleagues refute their hypothesis the caudal prefrontal cortex -- a brain region critical for attention -- is Ritalin's main site of action in the brain. To arrive at this conclusion, the researchers recorded large populations of neurons in this brain region as two male macaque monkeys performed a demanding visual attention task. The team did not observe any differences in neuronal activity after administration of the drug compared to a placebo, even at doses that improved the monkeys' performance on the task.

What you don't look for can't hurt your share price...

Only nine of 185 randomized clinical trials and 23 of 259 non-randomized studies and patient reports of methylphenidate in children and adolescents with ADHD reported assessment of psychotic symptoms.