This study was conducted to delineate the relationship between self-reported side effects and psychopathology in schizophrenia patients. Patients with schizophrenia completed the Liverpool University Neuroleptic Side Effects Rating Scale for subjective side effects and were evaluated with the Positive and Negative Syndrome Scale for their psychopathology. Based on a series of multiple linear regression analyses, we derived a model accounting for the relationships among the specific domains of psychopathology and red herring (RH) items of the Liverpool University Neuroleptic Side Effects Rating Scale in predicting subjective side effects. The model with anxiety/depressive symptoms and RH serving as mediators between positive symptoms and side effects was found to show good fit. Positive symptoms caused mostly anxiety symptoms and tendency to report RH items, whereby resulting in over-generalized reporting of subjective side effects. However, a large proportion of variance of side effects was explained by RH, which was only partially explained by positive symptoms alone. Therefore, patients with severe levels of positive and anxiety/depressive symptoms may be prone to nocebo-like effects of antipsychotics. Studies that include acute stage patients presenting severe levels of these symptoms should not rely only on the subjective report of side effects but also apply objective measures.
aDepartment of Psychiatry and Behavioral Science, Institute of Human Behavioral Medicine, Seoul National University College of Medicine
bDepartment of Natural Science, Seoul National University
cDepartment of Neuropsychiatry, Seoul National University Hospital, Seoul, Korea
Correspondence to Dr Yong Sik Kim, MD, PhD, Department of Psychiatry and Behavioral Science, Institute of Human Behavioral Medicine, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-Gu, Seoul 110-744, Korea
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Samuel Suk-Hyun Hwang and Dong Chung Jung equally contributed to this study
Received 11 May 2009 Accepted 3 November 2009