Psychiatric symptoms mediate the effects of neurological soft signs on functional outcomes in patients with chronic schizophrenia: A longitudinal path-analytic study

Abstract

Neurological soft signs (NSS) in motor coordination and sequencing occur in schizophrenia patients and are an intrinsic sign of the underlying neural dysfunctions. The present longitudinal study explored the relationships among NSS, psychiatric symptoms, and functional outcomes in 151 Chinese patients with chronic schizophrenia across a 6-month period. The participants completed neurological assessments at baseline (Time 1), psychiatric interviews at Time 1 and 3-month follow-up (Time 2), and self-report measures on daily functioning at 6-month follow-up (Time 3). Two possible (combined and cascading) path models were examined on predicting the functional outcomes. Direct and indirect effects of Time 1 NSS on Time 3 functional outcomes via Time 2 psychiatric symptoms were evaluated using path analysis under bootstrapping. Motor coordination and sequencing NSS did not have significant direct effects on functional outcomes. Motor coordination NSS exerted significant and negative indirect effects on functional outcomes via psychiatric symptoms. These results contribute to a better understanding of the determinants of functional outcomes by showing significant indirect pathways from motor coordination NSS to functional outcomes via psychiatric symptoms. That motor sequencing NSS did not affect functional outcomes either directly or indirectly may be explained by their trait marking features.

A systematic review of the prognostic value of motor abnormalities on clinical outcome in psychosis

“…The other 23 studies related MAs to symptom severity measured on clinical evaluation scales: 13 of them, with samples ranging from 17 to 10,000, found a significant relationship between MAs and more severe positive, negative and/or overall symptom severity. This applies for elevated baseline scores of NSS (Behere, 2013;Fong et al, 2017;Mittal et al, 2007a;Sambataro et al, 2020), presence or development of tardive dyskinesia (Eberhard et al, 2006;Tenback et al, 2007;van Os et al, 2000), and/or (a combination of) other MAs, such as parkinsonism, akinesia, akathisia, dyskinesia, dystonia, and catatonia (L. Chen et al, 2013;Dollfus and Petit, 1995;Farreny et al, 2018;Peralta and Cuesta, 1999;Schennach-Wolff et al, 2011;Vauth et al, 2021). One study found results that indicated a relationship in the opposite direction between MAs and symptomatic outcome: an open-label trial with risperidone in 36 antipsychotic-naïve patients with schizophrenia significantly related development of parkinsonism to clinical improvement over five weeks (Venkatasubramanian et al, 2013).…”

“…Eight studies related MAs to social functioning and/or quality of life at follow-up. Six of these studies found that MAs, including NSS, dyskinesia, parkinsonism, akathisia and dystonia, were linked to poor (psycho)social functioning at follow-up (Ascher-Svanum et al, 2008;Behere, 2013;Chen et al, 2013;Fong et al, 2017;Park et al, 2016;Vauth et al, 2021). One study showed that akathisia scores contributed to poor general health on the six-dimensional health state short form (SF-6D) (Siani et al, 2016).…”