Covariation between motor signs and negative symptoms in drug-naive subjects with schizophrenia-spectrum disorders before and after antipsychotic treatment

Objective: To examine the covariation between negative symptoms and motor signs in a broad sample of drug-naïve subjects with schizophrenia-spectrum psychoses before and after inception of antipsychotic medication.

Methods: One-hundred and eighty-nine antipsychotic-naïve subjects with DSM-IV schizophrenia-spectrum psychoses were assessed for negative symptoms including affective flattening, alogia, avolition/apathy and anhedonia/associality, and motor signs including catatonia, parkinsonism and dyskinesia. We examined the association between negative and motor features at baseline, 4-weeks after inception of antipsychotic treatment and that of their mean change over the treatment period, such as their trajectories and treatment response pattern.

Results: At the drug-naïve state, motor signs were strongly related to affective flattening and alogia (p<0.01); at 4-weeks, most negative and motor features were significantly interrelated (p<0.01); mean change of motor signs and negative symptoms tended to be unrelated. This association pattern was irrespective of levels of positive symptoms. Ratings of negative symptoms, excepting affective flattening, improved after treatment (p<0.001) while motor ratings showed divergent trajectories with catatonia improving (p<0.001), parkinsonism worsening (p<0.001) and dyskinesia remaining unchanged (p>0.01). Although to a different extent, motor and negative features showed drug-responsive, drug-worsening, of drug-unchanged patterns of response to antipsychotic medication. The main predictors of negative and motor features in treated subjects were their corresponding baseline ratings (p<0.001).

Conclusions: Negative and motor features are differentiated, but to some extent, overlapping domains that are meaningfully influenced by antipsychotic medication. At the drug-naïve state, motor signs and the diminished expression domain of negative symptoms may share underlying neurobiological mechanisms.