A Contribution to The Aetiology of Manic-Depressive Insanity (1940)

Section I

 Age Incidence of Manic‑Depressive Insanity

For this purpose the records of 759 male and 1,773 female cases could be analysed. From the history sheets a note was made of the earliest age at which a manic‑depressive psychosis appeared, irrespective of actual admission to clinic or hospital. The single criterion was that the patient should have shown at that time sufficiently clear symptoms to allow a certain diagnosis of manic‑depressive illness. The figures are given in columns 2 and 6 of Table 1.

As may be seen, first illnesses occurred at all ages from 13 to 74 and over. In the adjoining columns 3 and 7 are census figures for Bavaria for the years 1905, 1916, and 1925, summed together. The 2,532 cases which form the material for this table were admitted to the Kraepelin Clinic between the years 1903 and 1922. The summed census figures for Bavaria represent a fair picture of the popula­tion from which these cases were drawn at the time and are, of course, influenced by the changes caused by the Great War. The figures of columns 4 and 8 are the result of the division of those of col­umns 2 and 6 by those of columns 5 and 7 and represent a frequency per 100,000 for both sexes and for every year of life. They do not, of course, have any value as absolute figures, but are of con­siderable interest as an expression of the relative frequency of manic‑depressive illness from year to year of life. Put into the form of a curve, they are given in Figure 1;

for this purpose av­erage values of five‑year periods were used. instead of the empi­rical yearly figures. From this table and from this curve certain facts may be read. The frequency of manic‑depressive illness would appear to be almost double as great in women as in men. This, however, cannot be taken as actually true; for disturbing factors have to be taken into consideration, as will be discussed later. Both the curves for women and for men are diphasic; in the male curve the peaks are at the years 36 and 54, in the female curve at 38 and 48. The plateau of the curve appears to be more extended for the men than for the women, reaching for the former to the sixty‑fifth year, whereas for the women it begins to drop rapidly after the fifty‑fourth year. It is not uninteresting that the chief danger period for both sexes is more truly represented by the period from the thirtieth to the sixtieth year than, as has hitherto been generally assumed, from the twentieth to the the fiftieth year. Dahlberg and Stenberg¹ have provided a material which may be used for comparison with mine, and the two are placed side by side in Table 2. Corresponding graphs have been drawn and are given in Figure 2.

    In these curves there is no material difference between men and women in my material. Both the male and the female curve are very similar to the female curve of Dahlberg and Stenberg. 

With Dahlberg and Stenberg, however, the male curve is very differently formed. Here the time of greatest danger is shifted still further towards the later ages. I am inclined to think that the differ­ences between these curves are in large part accidentally deter­mined. It will be noticed that my curves, which are founded on a considerably larger material, take a middle position between the two curves of Dahlberg and Stenberg.

(1) Dahlberg, G. and S. Stenberg. Z. ges. Neurol. Psychiat. (1931) 133.