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

The Frequency of Psychiatric Abnormalities in the Parents and the Children of the Propositi

The results of my investigations are summarized in tabular form in Tables 12 ‑ 2. For the calculation of frequencies of manic‑depressives I have used both Weinberg's shorter method and. Strömgren's method, and put the results side by side. For the frequency of manic‑depressives among the parents, it makes very little difference to the result which method is used, but among the children the differences between the results obtained by the two methods are very great. Furthermore, I have thought it de­sirable to give separately the frequency of cases who have been treated in some clinic or hospital. This is a much smaller number than the total number of those whom I should wish to diagnose¹ as manic‑depressive. Schulz¹ has drawn attention, among the "manic‑depressives" whom other investigators have found in manic‑depressive families, to the high frequency of cases who have never been treated in any institute or hospital. If it is only these "treated" cases whom one is prepared to recognize as true manic­depressives, the frequency of manic‑depressive insanity among the relatives of manic‑depressives must be estimated much lower than would otherwise be the case.

    As regards the criteria of diagnosis of the secondary cases, it is necessary to say that I have regarded as "cyclothymic per­sonalities" all those persons who have shown well‑marked swings of mood lasting considerable periods, varying from overactivity and elation to inertia and depression, or varying from normal in one of these directions only, or persons of a permanently depressed or boisterous overactive temperament, these abnormalities of mood being so marked as to be frankly obvious to friends or relatives but not being so extreme as to lead. to illness or temporary or permanent incapacity. In the latter event I have included such persons among the psychotics, using therefore a purely social cri­terion as to what shall necessitate a diagnosis of manic‑depressive insanity ‑ that of social incapacity of such a degree that it has necessitated medical treatment.

     In regard to psychiatric abnormalities other than schizophrenia and manic‑depressive insanity, I have made use, for the calculation of frequencies, solely of Weinberg's shorter method in a manner which is given in Table 11.

     To state the more important facts to be obtained from the tables I found a frequency of 11.5% manic‑depressive psychoses among the parents and of 22.2% among the children. Certain diff­erences are shown between the groups 'A" and "B” propositi (Table 24). Manic‑depressive insanity is more frequent and schizophrenia less frequent in the relatives of "A" than in the relatives of "B" propositi. I do not regard these differences as necessarily without significance, and this matter will be discussed later. The manic‑depressive psychoses exhibited by parents and. children show only a limited similarity with those of the propositi. The main differences are: that for the most part they only fell ill once, and frequently not so severely as the propositi themselves. This is readily explained by the consideration that the propositi represent a special selection for hospitalized eases and for those who have had a number of illnesses. A short description of a number of these psychiatrically abnormal relatives, together with the diagnosis I saw fit to make given in brackets, is provided in the case material at the end of the thesis.

    The high value for the frequency of manic‑depressive insanity among the children, which one obtains by use of Strömgren's method, may appear somewhat unlikely. On this point it must be remarked that the case material which was used by me for the construction of Table 1 consisted entirely of hospitalized cases. It is quite possible that this does not provide the best standard material with which to control a group of cases, the majority of which at the time of observation had. not been admitted to any hospital at any period of their lives. This is an unavoidable wealmess in the applicability of Strömgren's method. I have therefore thought it desirable to make use of Weinberg's morbidity table as a control. The results of the calculation, for all children taken together, are given in Table 25. The total product of all the probabilities of column h is 0.8030. From this the probability of a child of a manic‑depressive himself developing a manic‑depressive psychosis, which is but another way of express­ing the frequency of manic‑depressives among the children of manic­depressives, is 19.70%. The agreement between this figure and the figure of 22.2% found by the use of Strömgren's method is not bad. Although it must be agreed that neither of the two methods has a very high degree of certainty and accuracy, nevertheless the de­gree of confirmation obtained is more in favour of the Strömgren method than of the use of Weinberg's shorter method as it has been employed here.

(1) Z. psych. Hyg. (l937). 10 : 39