Discerning undifferentiated anxiety from syndromal anxiety in acute-phase schizophrenia

BACKGROUND: Literature on anxiety in schizophrenia is confined to well-established diagnostic syndromes and the diagnostic category of unspecified anxiety disorder has not been quantitatively verified in this population. This study examined whether anxiety that is not differentiated into the well-established syndromes is empirically discernible from syndromal anxiety and no anxiety in acute-phase schizophrenia. METHODS: After sampling 111 acute-phase schizophrenia patients, they were stratified into three groups: syndromal anxiety; undifferentiated anxiety; and without anxiety disorder. The groups were compared statistically in two data sets on measures for anxiety, psychotic severity, depressive features, akathisia and medication use. RESULTS: On two measures of anxiety and for both data sets, the groups were significantly different without evidence of a confounding influence by akathisia, medication, or psychotic severity. The undifferentiated group was different from the syndromal group on the Staden Schizophrenia Anxiety Rating Scale (S-SARS) for both data sets (mean difference = 7.46, p < 0.001; mean difference = 7.69, p < 0.002) and on the Hamilton Anxiety Rating Scale for the one data set (mean difference = 14.68, p < 0.001) but not for the replicative data set (mean difference = 1.49, p = 0.494). The undifferentiated anxiety group was different from the no anxiety group for the respective data sets on both anxiety scales (S-SARS: mean difference = 8.67, p < 0.001; mean difference = 8.64, p < 0.001)(HAM-A: mean difference = 6.05, p < 0.001; mean difference = 8.67, p = 0.002). When depressive features had a confounding effect, it was small relative to the group differences. CONCLUSIONS: The results suggest some patients in acute-phase schizophrenia present with undifferentiated anxiety that is discernible from both syndromal anxiety and those without an anxiety disorder. This finding may serve as empirical grounds for clinicians to recognise undifferentiated anxiety in acute-phase schizophrenia, and for further research into the clinical importance of undifferentiated anxiety in this population.