Deficit schizophrenia linked to increased risk for tardive dyskinesia
MedWire News: Patients with the deficit subtype of schizophrenia are more likely to experience tardive dyskinesia (TD) than those with nondeficit schizophrenia, research shows.
Writing in the journal Acta Psychiatrica Scandinavica, Susan Telfer (Gartnavel Royal Hospital, Glasgow, UK) and colleagues explain that "despite comparable antipsychotic exposure, some [schizophrenia] patients experience involuntary movements yet others do not."
To investigate whether the deficit subtype of schizophrenia is associated with a greater risk for TD than nondeficit schizophrenia, the team studied data on 131 patients with the mental health disorder from Nithsdale in Scotland.
All of the patients were assessed for the deficit form of schizophrenia, defined by the presence of primary, enduring negative or deficit symptoms, and those without this subtype were defined as having nondeficit schizophrenia.
The Abnormal Involuntary Movements Scale (AIMS) was used to assess the patients for TD, with at least two scores of 2 or at least one score of 3 on the AIMS defining presence of the condition.
In total, 31 (23.7%) patients were identified as having deficit schizophrenia.
There were no significant differences between the deficit and nondeficit schizophrenia groups regarding age, exposure to antipsychotic medications, duration of illness, or relationship and employment status, the researchers note.
However, they found that 48.4% of patients in the deficit schizophrenia group had TD compared with just 24.0% of those in the nondeficit group.
Indeed, deficit schizophrenia patients were 2.97 times more likely to have TD than those in the nondeficit group.
Telfer and team conclude: "These findings indicate that there is an association between TD and deficit schizophrenia, but further research using a longitudinal design may be required to support the proposal that the pathological process underlying deficit schizophrenia can predispose to the development of TD."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Mark Cowen