The bipolar spectrum model suggests that several patient presentations not currently recognized by the DSM warrant consideration as part of a mood disorders continuum. These include hypomania or mania associated with antidepressants; manic symptoms which fall short of the current DSM threshold for hypomania; and depression attended by multiple non-manic markers that are associated with bipolar course. Evidence supporting the inclusion of these groups within the realm of bipolar disorder (BP) is examined. Several diagnostic tools for detecting and characterizing these patient groups are described. Finally, options for altering DSM-IV criteria to allow some of the above patient presentations to be recognized as bipolar are considered. More data on the validity and utility of these alterations would be useful, but limited changes appear warranted now. We describe an additional BP Not Otherwise Specified (BP NOS) example which creates a subthreshold hypomanic analogue to cyclothymia, consistent with existing BP NOS criteria. This change should be accompanied by additional requirements for the assessment and reporting of non-manic bipolar markers.