An administrative law judge was impermissibly “playing doctor” when she concluded a woman seeking disability benefits suffered severe migraines because she stopped taking a prescribed medication, a federal judge held.In a written opinion last week, U.S. Magistrate Judge Iain D. Johnston also concluded the ALJ’s diagnosis was faulty.He directed the ALJ to reconsider her denial of the woman’s claim for Social Security disability benefits.The claimant — identified in the opinion as Catherine P …