Background: Negative symptoms are known to be present in the prodromal stage of psychotic disorders, yet little is known about their prevalence. Studies examining the presence of negative symptoms in ultra-high risk (UHR) populations have shown some limitations, notably failing to control depression. The objective of this study was to examine the prevalence of negative symptoms in the presence of significant levels of depression and in the absence of such symptoms (primary negative symptoms) over 1 year and to examine differences in negative symptoms in psychosis converters and non-converters.
Methods: Participants were 123 individuals at UHR for the development of psychosis receiving follow-up for a period of 2 years. Negative symptoms and depression were measured using the Scale for the Assessment of Negative Symptoms and the Montgomery-Asberg Depression Scale at baseline, 6 and 12 months post-admission.
Results: At baseline, the prevalence of negative symptoms and primary negative symptoms was 76.4% and 32.7%, respectively. Whereas the prevalence of negative symptoms was significantly decreased at 6 months, the prevalence of primary negative symptoms was similar at all time points. Negative symptoms at baseline were not different between later converters and non-converters to psychosis.
Conclusion: Our findings confirm the presence of secondary and primary negative symptoms in individuals at UHR, but suggest a differential trajectory of both measures over time. Future studies should include larger UHR groups and focus on the investigation of intra-individual changes in primary negative symptoms over time and further explore their potential role for psychosis conversion.
Keywords: depression; negative symptoms; primary negative symptoms; ultra-high risk for psychosis.
© 2016 John Wiley & Sons Australia, Ltd.