Millions take it for asthma and allergies, but Singulair is under scrutiny. The popular drug, prescribed for decades, is linked to an array of psychiatric symptoms—from nightmares and depression to suicidal thoughts.
As regulators slap its packaging with warnings of neuropsychiatric issues and patients recount similar experiences, a question looms: How did a once-celebrated treatment become problematic for some? As families seek answers, scientists work to unravel how a medication meant to ease breathing could cloud the mind.
