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

Thesis Dissertation for the Degree of M. D., Cambridge 1940 (previously unpublished, © The Estate of Eliot Slater)



The Aetiology of Manic-Depressive Insanity
E. T. O Slater, M.B., M.R.C.P, D.P.M.



The investigations that are the subject of this thesis were carried out at the Forschungsanstalt für Psychiatrie in Munich. At this institute a card‑index of all the patients admitted to the University Clinic during the professorship of E. Iaepelin was kept over the years 1903 to 1922. This very large material has been the subject of a number of intensive though partial investigations into the inheritance of various psychiatric states under the inspiration of Professor E. Rüdin. It was my original intention to carry out an investigation into the heredity of manic‑depressive psychoses; but, in the course of this investigation, a number of other problems of aetiology showed themselves to be of interest and capable of exmination.

    The total manic‑depressive material of the card‑index provided data for an examination of the age incidence of the psychoses; se­lecting a group of cases from this material by criteria which will be described later, I examined other problems related to inherent and accidentally imposed rhythms of appearance of the illness, to the manic‑depressive constitution, and. to the influence, Importance, and specificity of inherited factors. It will be seen that these prob­lems have a rather loose connection with one another, though they all fall under the general heading of aetiology. Of them all, the prob­lems of inheritance are the most important and have been gone into in greatest detail; and it is accordingly in this section of the thesis that the methods of selection and preliminary spade‑work will be described.

    The thesis is divided into the following sections:

    I.          Factors governing the temporal appearance of manic‑depressive psychoses.

                (a) Age Incidence.
                (b) Incidence and Season of the Year.
                (c) Yearly Rhythm of Incidence.
                (d) Longer Natural Rhythms.
                (e) Difference in Length of Duration of Earlier and Later Intervals between Illness.

    II.         Hereditary and Constitutional Factors.

                (a) Selection of the Material.
                (b) Causes of Death in Manic‑Depressive Families.
                (c) Occupation and Social Level.
                (d) Preliminary Calculations.
                (e) The Frequency of Psychiatric Abnormalities in the Parents and Children of the Propositi. 
                (f) Comparison with the Results of other Investigations.
                (g) The Expectation of Manic-Depressive Pszchoses for the General Population.
                (h) The Relationship between Manic-Depressive Insanity and Schizophrenia.
                (i) The Colouring of Schizophrenic Psychoses occurring in Manic-Depressive Families.
                (j) The Inheritance of Manic-Depressive Insanity.

   III.        Case Material