Evidence for a familial correlation between increased reactivity to stress and positive psychotic symptoms.
OBJECTIVE
This study tested the hypothesis that stress-reactivity may represent an intermediary phenotype underlying positive psychotic symptoms. It was examined whether: (i) stress-reactivity clusters within families of psychotic patients and (ii) stress-reactivity in relatives cosegregates with positive symptoms in patients.


METHODS
The sample consisted of 40 patients and 47 siblings of these patients. The Experience Sampling Method (ESM - a structured diary technique) was used to measure stress-reactivity. Positive symptoms in patients were measured with the Comprehensive Assessment of Symptoms and History.


RESULTS
Within-trait, cross-sib associations showed a significant association between stress-reactivity in the patient and stress-reactivity in their siblings. Significant cross-trait, cross-sib associations were established showing a significant association between positive psychotic symptoms in the patient and stress-reactivity in the sibling.


CONCLUSIONS
The findings show familial clustering of increased stress-reactivity, suggesting common aetiological influences, probably both genetic and environmental, underlying stress-reactivity in the siblings and patients. In addition, the results underscore the hypothesis that increased stress-reactivity is an unconfounded mechanism of risk underlying the positive symptoms of psychotic disorders.
Lataster
T
T
Department of Psychiatry and Neuropsychology, South Limburg Mental Health Research and Teaching Network, Euron, Maastricht University, Maastricht, the Netherlands.
Collip
D
D
Lardinois
M
M
van Os
J
J
Myin-Germeys
Inez
I
D000293:Adolescent; D000328:Adult; D000339:Affect; D005190:Family / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D017533:Marital Status; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000209:etiology* / Q000523:psychology; D012044:Regression Analysis; D035781:Siblings / Q000523:psychology; D012959:Socioeconomic Factors; D013315:Stress, Psychological / Q000150:complications* / Q000209:etiology / Q000523:psychology; D055815:Young Adult