Alogia, attentional impairment, and inappropriate affect: their status in the dimensions of schizophrenia.

Previous factor analyses have shown that at least three factors are needed to encompass the positive and negative symptoms of schizophrenia. Despite marked similarities across studies, it remains unclear whether certain symptoms such as alogia, attentional impairment, and inappropriate affect are more closely related to negative or positive symptoms. An exploratory analysis was undertaken of the separate items on the Scale for the Assessment of Positive Symptoms (SAPS) and Scale for the Assessment of Negative Symptoms (SANS) that constitute the global rating of alogia, as well as the global ratings of attentional impairment and inappropriate affect in 90 schizophrenic patients. Findings indicate that inappropriate affect loads significantly with bizarre behavior and positive formal thought disorder on a disorganization factor, whereas attentional impairment loads significantly on psychotic, disorganization, and negative symptom factors. The global rating of alogia appears to comprise both positive and negative symptoms, with the item poverty of content of speech loading on the disorganization factor, and other items such as poverty of speech, blocking, and increased latency loading on the negative symptom factor. It is concluded that three dimensions are needed to characterize the symptoms of schizophrenia as measured by the SAPS/SANS. The use of three dimensions may be a robust way to further explore the relationship between signs and symptoms and their underlying mechanisms in schizophrenia.