H. Verdoux et al., DOES FAMILIALITY PREDISPOSE TO BOTH EMERGENCE AND PERSISTENCE OF PSYCHOSIS - A FOLLOW-UP-STUDY, British Journal of Psychiatry, 168(5), 1996, pp. 620-626
Background. It has been suggested that in schizophrenia an association
exists between family history of schizophrenia and poor outcome on th
e one hand, and family history of affective disorders and good outcome
on the other. Method. We tested for associations between four-year ou
tcome and familiar loading for psychotic disorders in a mixed sample o
f 150 consecutively admitted patients with functional psychosis (schiz
ophrenia, psychotic affective disorders, other psychotic disorders) of
recent onset. For each proband, a familial loading score for (i) broa
dly defined psychotic disorder, (ii) schizophrenia, and (iii) affectiv
e disorder was calculated using information on relatives obtained thro
ugh the Family History Research Diagnostic Criteria method and direct
interviews of relatives with the Schedule for Affective Disorders and
Schizophrenia. Results. In our sample of psychotic patients, familial
loading for psychotic disorder predicted persistent negative symptoms
over the follow-up period (OR 1.5; 95% CI 1-2.2), especially in schizo
phrenia, and was also associated with more time hospitalised (P > 0.05
), and more social disability at follow-up (P < 0.05). Greater familia
l loading for schizophrenia predicted a greater likelihood of non-reco
very (OR 2.2; 95% CI 1.1-4.4) and a greater likelihood to have had per
sistent negative symptoms over the follow-up period (OR 1.7: 95% CI 0.
9-3.1). No association was found between outcome and familial loading
for affective disorder. Conclusions. We conclude that familiar loading
may be a continuous risk factor for some dimensions of clinical outco
me in the functional psychoses. This suggests that there is a continuu
m of genetic liability not only to the emergence of psychotic illness,
but also the subsequent chronicity of the disorder.