The shooter was "in therapy" for depression, so it can't be argued that his mental illness was being ignored. The common treatment for depression is prescription of an SSRI drug. That "treatment" seems to have a consistent history with mass shooters. There are already studies that cite that SSRI drugs are not recommended for people under age 24. That also comports with the age range for school shooters.
Yes, look at the eyes. They all seem to have that same insane, strung-out look.