"Positive" and "negative" movement disorders in schizophrenia

Area of Science:

• Psychiatry
• Neuroscience
• Clinical Psychology

Background:

• Clinical characteristics differentiating tardive dyskinesia (TD) from non-TD patients remain unclear.
• Previous research suggests TD in schizophrenia may correlate with positive symptoms, and drug-induced parkinsonism (DIP) with negative symptoms.

Purpose of the Study:

• To investigate the relationship between TD and DIP with specific psychopathology clusters in schizophrenic patients.
• To test the hypothesis that TD is associated with positive symptoms and DIP with negative symptoms.

Main Methods:

• Examined 47 institutionalized schizophrenic patients.
• Assessed TD and DIP using psychopathology clusters from the Positive and Negative Syndrome Scale.

Main Results:

• TD involuntary movements significantly correlated with the activation cluster (p < .01).
• DIP significantly correlated with the anergia cluster (p < .01).

Conclusions:

• Findings support TD as a facet of the positive syndrome and DIP as a feature of the negative syndrome in schizophrenia.
• Schizophrenic patients with positive symptoms may have higher TD risk; those with negative symptoms may have higher DIP risk.
• Proposes TD as a "positive" and DIP as a "negative" movement disorder.