Subclinical expression of schizophrenia-like symptoms in non-psychotic siblings of individuals with schizophrenia.

Subclinical expression of schizophrenia-like symptoms in non-psychotic siblings of individuals with schizophrenia Dear Editors, There have been numerous reports of mild psycho-pathology in the relatives of individuals with schizo-phrenia, including odd behaviors, social withdrawal, and difficulty with personal relationships. These features have been referenced as " schizotypal, " given their similarity to the psychopathology observed in individuals with schizophrenia, and viewed as evidence for the genetic basis of schizophrenia (e.g., Meehl, 1962). Recently , psychopathology in individuals with schizophre-plicability of this model to the expression of psycho-pathology in the relatives of individuals with schizo-phrenia has not been studied. The younger siblings of individuals with schizophre-nia are a particularly interesting group of relatives because they can still be at risk for developing the illness or its prodrome (Woods et al., 2001). Hence, we aimed to assess the factor structure of psychopathology in the non-psychotic siblings of individuals with schizophrenia and to determine whether it conformed to a model that is observed in individuals with schizophrenia. Notably, Hawkins et al. (2004) reported the absence of a dis-organization factor in individuals who meet criteria for the schizophrenia prodrome. Given that an expression of disorganization was not likely in our sibling population, this factor was not examined in this study. Thus, we hypothesized that the non-psychotic siblings of individuals with schizophrenia, still within the age of risk for developing the disorder, would exhibit subtle forms of positive symptoms, diminished expression, and social dysfunction. Participants were from a study of neuromorphology in individuals with schizophrenia and their siblings at the Conte Center for the Neuroscience of Mental Disorders at Washington University in St. Louis. This substudy included 40 non-psychotic siblings (mean age = 21.8 (SD = 3.5), 52.5% female, and 62.5% Caucasian) of individuals with schizophrenia. The recruitment procedures can be referenced elsewhere (Delawalla et al., 2006). Symptom domains were assessed via global ratings from the SAPS and SANS (Andreasen, 1983a,b). Indicators for positive symptoms were hallucinations and delusions. Indicators for diminished expression were affective flattening and alogia, and indicators of social dysfunction were anhedonia and avolition. Confirmatory factor analysis was estimated using LISREL-8.80 (Jöres-kog and Sörbom, 1996). Among the latent factors, we found that diminished expression was correlated with both positive symptoms (r = .57, p b .01) and social dysfunction (r = .48, p b .01), while the latter two were not correlated (r = .07, p = .71). All indicators loaded significantly …