John Frederick Joseph Cade AO (18 January 1912 – 16 November 1980) was an Australian psychiatrist credited with discovering (in 1948) the effects of lithium carbonate as a mood stabilizer in the treatment of bipolar disorder (then known as manic depression). In an age where the standard treatments for psychosis were electroconvulsive therapy and lobotomy, lithium had the distinction of being the first effective medication available to treat a mental illness.