Secondly, although all relatives were euthymic at the time of assessment, we cannot not rule out the hypothesis that they smoke to improve their mood (Berlin et al., 1995; Lerman et al., 1998), as being the parent of a schizophrenic patient may lead to depressive states. Similarly, we could not exclude the possibility of relatives smoking to improve cognitive deficits or due to a low socio-economic status, as shown for schizophrenic subjects.