134 Franz J. Kallmann 



strain arising from increasingly conspicuous signs of ageing, 

 these traits tend to lead to painful experiences in inter- 

 personal relationships, gradually overtaxing the adaptive 

 defense mechanisms. 



When a psychotic break with reality occurs, its symptoms 

 are characterized by the inability to find constructive avenues 

 for releasing anxiety generated by involutional changes. 

 Aetiologically, however, it is obvious that the causes of such 

 an involutional psychosis are multiple and always include a 

 long history of emotional instability determined genetically. 

 Admittedly, the biochemical correlates of this deficiency in 

 adjustive plasticity are still very much in need of clarification. 



Similar uncertainties exist with respect to the genetic 

 aspects of those pathological conditions which are specific to 

 the period of senescence. Sufficient information is not even 

 available regarding the least common and most easily recogniz- 

 able disorders known as Pick's, Alzheimer's and Jacob- 

 Creutzfeldt's diseases. Here, gross and relatively circum- 

 scribed brain lesions develop so dramatically and prematurely 

 that from a genetic standpoint it would be possible to think in 

 terms of specific disturbances produced by the effect of single 

 mutant genes (Essen-Moller, 1946; Jacob, Pyrkosch and 

 Strube, 1950; Klopfer, 1956; Malamud and Waggoner, 1943). 



Theories of simple dominance or recessiveness have been 

 advanced not only for these three special types of presenile 

 brain atrophy, but also for essential hypertension and cerebral 

 arteriosclerosis and the total group of disorders called senile 

 dementia. However, histologically verified family data are 

 still so scarce in this area that it would seem inadvisable to 

 eliminate polygenic modes of inheritance, even in the fairly 

 well-studied groups of Alzheimer's and Pick's diseases. 

 According to Sjogren, Sjogren and Lindgren (1948), the 

 theory of a simple dominant mode of inheritance has been 

 more clearly substantiated in Pick's than in Alzheimer's 

 disease. The observed morbidity rates for the parents and 

 sibs of affected persons are 19 and 6-8 per cent in Pick's 

 disease, and 10 and 3-8 per cent in Alzheimer's disease. 



