Susannah Cahalan

SC: [...] The Clock Test is ordinarily given to people with dementia or Alzheimer disease. It had no business being given to a 24-year-old . . . but my doctor, Souhel Najjar, had a brilliant stroke of insight and decided to use it to test me.

He first asked me to draw a circle—and I did after one aborted attempt. (I later learned that circle drawing is an overlearned practice that many people—even those with severe cognitive deficits—can do.) Then he asked me to write in the numbers. When he stared at the page, he nearly applauded. I had squished in all the numbers—1 through 12—on the right-hand side, entirely neglecting the left side of space. This proved to him that whatever I was suffering from was neurological—not psychiatric. It was the key that finally led to my final diagnosis.

Interview