Survey of cases of familial mental illness. L. S. Penrose, July 1945.

An investigation was made of all known cases of mental illness where more than one member of the family entered one of the Ontario Mental Hospitals. The materials is fairly complete for a period of 18 years. Analysis of the resulting data, on pairs of relatives, gave rise to the following conclusions of particular interest. (i) Schizophrenia, affective psychosis, senile psychosis, Huntington's chorea and mental defect are shown to be conditions which remain significantly true to type when mental disease occurs in different members of a family. As a rider to this, however, it is found that schizophrenia and affective psychosis are not very distinct entities and groups of closely related familial cases frequently include both diagnoses. (ii) Schizophrenia is a rare diagnosis in the fathers of patients and occurs in only 8.7% of fathers, as opposed to the 30.7% in the whole sample of relatives: it is not so rare in mothers (24.5%). (iii) The most frequent type of relationship in pairs of patients is sister and sister: next in frequency is the type brother and brother, then brother and sister. Mother and son, mother and daughter, father and daughter and then father and sone come next in order. Less frequent are uncle and nephew or uncle and niece and, again less frequent, aunt and nephew or niece; grandparents and grandchildren were rarely found. (iv) Fathers, diagnosed schizophrenic or first admitted below the age of 35, have more psychotic sons than psychotic daughters, but the reverse is true for mothers in the same categories. (v) Fathers diagnosed as having affective illness or first admitted at the age of 35 or over have more psychotic daughters than psychotic sons, but the reverse is true for mothers in the same categories. (vi) Male subjects with either schizophrenic or affective diagnosis and in early- or late-onset age groups, have more psychotic brothers than psychotic sisters. Similarly, female subjects have more psychotic sisters than psychotic brothers. (vii) Each main diagnosis group has its characteristic first admission age. (viii) The first admission age is earlier in males than in females for schizophrenics, and later in males than in females for affective disorders. (ix) Study of first admission ages in families indicates that parents and, particularly, grandparents are much older than children and, particularly, grandchildren at first admission. This effect is not attributed to progressive degeneration. (x) Male subjects show a significantly wider scatter of first admission ages than do female subjects.(ABSTRACT TRUNCATED AT 400 WORDS)