Staging systems in bipolar disorder: an <scp>I</scp>nternational <scp>S</scp>ociety for <scp>B</scp>ipolar <scp>D</scp>isorders <scp>T</scp>ask <scp>F</scp>orce <scp>R</scp>eport

Most studies to date indicate that globally defined late-stage patients have a worse overall prognosis and poorer response to standard treatment, consistent with patterns for end-stage medical disorders. We believe it is possible at this juncture to speak broadly of 'early'- and 'late'-stage bipolar disorder. Next steps require further collaborative efforts to consider the details of preillness onset and intermediary stages, and how many additional stages are optimal.