Table 4.

Multilevel mixed model results: regression coefficients of asymmetry (symmetry index) with the severity of psychopathology (CGI-SCH SI) (patients N = 188, number of measurements N = 468)^a.

	Symmetry indexb			N
	β	95% CI	p value
CGI-SCH SI
Positive	3.74c	0.35 to 7.13	0.031	462
Negative	1.40	−2.07 to 4.88	0.429	462
Depressive	0.37	−2.24 to 2.98	0.780	465
Cognitive	1.07	−2.15 to 4.30	0.514	461
Global	2.31	−0.65 to 5.27	0.126	462

CGI-SCH SI, Clinical Global Impression-Schizophrenia scale severity index; CI, confidence interval; UPDRS, Unified Parkinson Disease Rating Scale.

^aClinical assessments for all covariates in the model were completed in 468 measurements of 188 patients, with parkinsonism in the upper/lower limb(s) in at least one measurement.

^bHigher values of the symmetry index indicate a higher degree of asymmetry. Symmetry index of the UPDRS motor items 20–26 = (mean absolute difference UPDRS left and right)/(sum of the mean UPDRS left and right).

^cCoefficient was considered significant (p < 0.05).

The β coefficients in this table represent regression coefficients for the symmetry index as independent, and the CGI-SCH SI scales as dependent variables.

The β coefficients were corrected for the following covariates: age, sex, dosage of antipsychotics (defined daily dose), diagnosis (schizophrenia/other), concomitant anticholinergic use (yes/no), presence of movement disorders (parkinsonism, dyskinesia, dystonia, akathisia as continuous variables) and for the interaction between symmetry index and age.

The symmetry index was added as a squared covariate in the regression model, suggesting a non-linear relationship between the symmetry index and severity of psychopathology.