A first study of the statistics of insanity and the inheritance of the insane diathesis / by David Heron.

  • Heron, David
Date:
1907
Catalogue details

Licence: In copyright

Credit: A first study of the statistics of insanity and the inheritance of the insane diathesis / by David Heron. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    actually complete, the members of the same stock coming- to the same asylum ; (ii) Pearson's Family Records, indicate an even higher percentage (see Appendix). (iii) the argument from tuberculosis is not valid; the present insanity data are more complete than the tuberculosis data, because the mean age of first attack is higher and because the families have been under observation during a longer period ; yet the unmodified record gives a sensibly lower percentage of offspring attacked than in the case of tuberculosis, namely 25 per cent, as against 30 per cent. There is no reason why the incidence should be the same in the two cases unless we start with some definite theory as to inheritance, e.g. the Mendelian. In Table IV below there is, however, little to warrant the application of that doctrine to the present data. Table IV. Nature of Parents as to Insanity Total Offspring Percentage Offspring Insane Sane Insane Sane Both Sane 314 1179 21 79 One Insane 93 299 24 76 Both Insane 4 4 50 50 Now these results are, remembering the probable error of the last result, singularly close to those found by Pearson for pulmonary tuberculosis'. They compel us to consider sanity as dominant, which involves the following scheme: Table V. Matings Expected to have Diathesis Recorded to have Diathesis Tuberculosis Insanity (RJi) X (BR) (RR) X (DR) (DR) X (DR) 100 per cent. 50 per cent. 25 per cent. 57 per cent. 29 per cent. 21 per cent. 50 per cent. 24 per cent. 21 per cent. No argument in favour of Mendelism seems possible on these figures t. Here, as in the case of tuberculosis, there is no obvious reason why the expectation should be so much more closely fulfilled by the record in the third mating than in either of the other two. No great stress is really to be laid, however, on the apparently close agreement of the two diseases, because the record for insanity is probably much more complete. The question of how far other members of the patient's sibship would be * A First Study of the Statistics of Pulmonary Tuberculosis, Drapers' Research Memoirs, Dulau & Co., 1907. t Exactly as in the tuberculosis data, the percentages required to complete the Mendelian proportions are wholly different in the three cases, whereas we should expect them to be the same. E. S. II. 3
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