“…From Table 4, it can be seen that two out of eight studies 5,12,14,26,29-32 found a statistically significant gender association with conversion, with one finding that female patients converted more frequently 29 and one that they converted less frequently. 32 Among eight studies investigating age at onset, 5,12,14,26,[30][31][32][33] five found that earlier onset was associated with a higher risk of conversion. 5,12,26,31,33 A total of four studies investigated number of depressive episodes, 14,28,31,33 all finding that the risk of conversion increased statistically significantly with the number of depressive episodes.…”