Concurrent validation of schizotaxia: A pilot study

Background: Many first-degree relatives of patients with schizophrenia show deficits in clinical, neuropsychological, neurobiological and social domai ns, in the absence of psychosis. We recently reformulated Meehl's concept o f schizotaxia to conceptualize the liability to schizophrenia, and we propo sed preliminary criteria based on the presence of negative symptoms and neu ropsychological deficits. Here we investigate the concurrent validity of sc hizotaxia by comparing a group of subjects who met criteria for schizotaxia with a group who did not on independent measures of clinical function, and on lifetime rates of selected comorbid psychiatric disorders. Methods: Twenty-seven adults who were first-degree, biological relatives of patients with schizophrenia were evaluated for schizotaxia based on our pr edetermined criteria involving negative symptoms and neuropsychological def icits. Subjects also received portions of the Diagnostic Interview for Gene tic Studies, the Structured Interview for Schizotypy, the Family Interview for Genetic Studies, the DSM-IV Global Assessment of Functioning, the Physi cal Anhedonia Scale, the Social Adjustment Scale and the Symptom Checklist- 90-Revised. Subjects who met criteria for schizotaxia were compared with th ose who did not on each of the clinical measures, and on their rates of com orbid DSM-IV psychiatric diagnoses. Results: Eight subjects met criteria for schizotaxia, and 19 did not. Subje cts with schizotaxia showed significantly lower levels of function on each of the clinical scales. Differences in comorbid psychiatric diagnoses were not significant, although the rate of lifetime substance abuse diagnoses in the schizotaxic group (50%) approached levels that are often seen in schiz ophrenia. Conclusions: These findings provide the first evidence of concurrent valida tion for a proposed syndrome of schizotaxia. They, are also consistent with the view that the vulnerability to schizophrenia may be defined, at least partially, although larger studies to assess both the concurrent and predic tive validity schizotaxia will be required to confirm these results. Biol P sychiatry 2001; 50:434-440 (C) 2001 Society of Biological Psychiatry.