1) Mental disorders are common in the United States, with 1 in 5 adults experiencing symptoms and 1 in 25 having a severe illness, though the causes are not fully understood. 2) Different treatments for mental illnesses like schizophrenia have been used throughout history, from trephining to modern medications, but one size does not always fit all patients due to individual differences. 3) Sir William Osler helped revolutionize how doctors perceive and treat patients in a more individualized, patient-centered way; this approach may be particularly important for effectively treating complex mental illnesses.