Parkinsonism is the condition of having any combination of the symptoms commonly found in Parkinson’s disease — tremors, slow movement, problems with speech or muscle stiffness — and is typically the result of the loss of dopamine-containing nerve cells (neurons).
For the study, the researchers detected parkinsonism in 15 (19.5 percent) of 77 patients with first-episode psychosis who had never taken antipsychotic medication.
From the beginning, patients with parkinsonism tended to perform slightly worse than those without the disorder in a range of neuropsychologic tests.
The patients were then tested again at one and six months. During this time, symptoms of parkinsonism strongly correlated with several measures of memory, executive functioning, and attention. At six months, patients with parkinsonism had poorer scores than those without in several areas.
“These results emphasize the relevance of the assessment of parkinsonism signs prior to starting to administer antipsychotic drugs,” said lead study author Manuel Cuesta of the Complejo Hospitalario de Navarra in Pamplona, Spain and colleagues.
“These cognitive impairments seem to represent core manifestations and be the most critical determinants of functioning and quality of life in schizophrenia and other psychoses, and it has been hypothesized that they may have common psychological and neurobiological substrates,” said the researchers.
However, the differences in scores between the beginning of the study and 6 months were not significantly different between the groups; the differences at 6 months arose from slight differences at baseline combined with slightly different rates of change during follow-up.
The link between parkinsonism and neurocognition was not affected by the type of antipsychotic medication that patients were given during follow-up.
The researchers suggest that their findings fit with the dopamine hypothesis of schizophrenia. For example, hypokinesia (slower body movements) and rigidity were more strongly linked to cognitive problems than was tremor, said the researcehrs.
Psychosis is defined as a loss of contact with reality. The symptom(s) can have many different causes and may be transient, intermittent, short term or part of a longer term psychiatric condition. Psychosis often involves hallucinations and/or delusions.
Source: Schizophrenia Bulletin