Objectives: Stable-phase
schizophrenia comprises two distinct entities namely Major Neuro-Cognitive
Psychosis (MNP) and simple NP (SNP), which are defined by neuroimmune and neurocognitive abnormalities.Methods: This study investigates associations of psychomotor retardation (PMR), clinical and
biomarker characteristics of
schizophrenia. We recruited 40 healthy controls and 79
schizophrenia patients and measured
IgA responses to
tryptophan catabolites (TRYCATs),
IgM to
malondialdehyde and nitroso (NO)-cysteinyl, CCL-11, an immune activation index based on
cytokine levels, and motor screening task (MOT) scores.Results: PMR differentiated
schizophrenia from controls and MNP from SNP. In addition, PMR was strongly associated with impairments in executive functions and episodic and semantic memory, psychotic, hostility, excitation, mannerism and negative (PHEMN) symptoms. Around 50% of the variance in PMR was predicted by the cumulative effects of the immune activation index, CCL-11, TRYCATs, NO-Cysteinyl and natural
IgM. PRM can reliably be combined with PHEMN symptoms, memory and executive impairments into one latent vector reflecting overall severity of
schizophrenia.Conclusions: PMR is a key psychopathological feature of
schizophrenia mainly MNP. In addition, PMR may be driven by deficits in the compensatory immune-regulatory system and increased production of neurotoxic immune products, namely TRYCATs,
IgM to NO-cysteinyl, and CCL-11, an endogenous cognition deteriorating
chemokine.