(b)

Author (year)	Duration of follow-up	Prevalence	Definition
Makanjoula (1985) [26]	Five years	53% of manic patients	M ≥ 2, D = 0
Solomon et al. (2003) [30]	20 years	27 subjects had the diagnosis of unipolar mania at the time of entry. Seven of these did not suffer any depressive episodes during the 15- to 20-year follow-up.	Onset with M/HypoM, D = 0 for entire follow-up period
Dakhlaoui et al. (2008) [11]	Five years	65.3% of all bipolar I patients	M ≥ 2 and at least 5 years of follow-up, D = 0

D: depressive episode; M: manic episode; HypoM: hypomania.