title: Reduced sense of agency in chronic schizophrenia with predominant negative symptoms.
abstract: Self-disturbances in schizophrenia have been regarded as a fundamental vulnerability marker for this disease, and have begun to be studied from the standpoint of an abnormal "sense of agency (SoA)" in cognitive neuroscience. To clarify the nature of aberrant SoA in schizophrenia, it needs to be investigated in various clinical subtypes and stages. The residual type of chronic schizophrenia with predominant negative symptoms (NS) has never been investigated for SoA. Accordingly, we investigated SoA by an original agency attribution task in NS-predominant schizophrenia, and evaluated the dynamic interplay between the predictive and postdictive components of SoA in the optimal cue integration framework. We studied 20 patients with NS-predominant schizophrenia, and compared with 30 patients with paranoid-type schizophrenia and 35 normal volunteers. NS-predominant schizophrenia showed markedly diminished SoA compared to normal controls and paranoid-type schizophrenia, indicating a completely opposite direction in agency attribution compared with excessive SoA demonstrated in paranoid-type schizophrenia. Reduced SoA was detected in experimental studies of schizophrenia for the first time. According to the optimal cue integration framework, these results indicate that there was no increase in compensatory contributions of the postdictive processes despite the existence of inadequate predictions, contrary to the exaggerated postdictive component in paranoid-type schizophrenia.
authors.affiliation: Department of Neuropsychiatry, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. Electronic address: takaki@xa3.so-net.ne.jp.
authors.forename: Takaki
authors.initials: T
authors.lastname: Maeda
authors.forename: Keisuke
authors.initials: K
authors.lastname: Takahata
authors.forename: Taro
authors.initials: T
authors.lastname: Muramatsu
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Okimura
authors.forename: Akihiro
authors.initials: A
authors.lastname: Koreki
authors.forename: Satoru
authors.initials: S
authors.lastname: Iwashita
authors.forename: Masaru
authors.initials: M
authors.lastname: Mimura
authors.forename: Motoichiro
authors.initials: M
authors.lastname: Kato
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000150:complications*; D012565:Schizophrenic Psychology; D012678:Sensation Disorders / Q000209:etiology*; D013223:Statistics as Topic; D018709:Statistics, Nonparametric
keywords: Dopamine; Glutamate; Optimal cue integration; Post-diction; Prediction; Self-disturbance; Sense of agency