Mental illness and stability

 The concepts of mental illness and mental stability

have also been suggested as variables in the incidence of

cancer. These concepts have been investigated both retro-

spectively and prospectively.

 In two follow-up studies of patients with depressive

illness, Kerr, Shapira, and Roth (1969) and Whitlock and

Siskind (1979) found that cancer deaths were significantly

higher ( p <.05) than expected in males. However, these

findings were not confirmed by other researchers (Evans,

Baldwin, & Gath, 1974; Niem & Jaaskelainen, 1978) whose

results showed no increase in deaths from cancer among

patients with unipolar depressive illness. Other research

(Rassidakis, Kelepouris, Goulis, & Karraiossefidis, 1972)

reported a lower than expected incidence of deaths from

cancer among schizophrenic patients but, according to Fox

(1978), insufficient data were given to show that they

exercised proper controls.

 In a prospective study by Hagnell (1966) a statisti-

cally significant association ( p <.05) was found between a

personality trait of "substability," said to be similar to

Eysenck's extraversion dimension, and cancer. However, both

the sample size (20 males and 22 females) and the statistical

analysis have been criticized (Fox, 1978).