Early neuropsychiatric symptoms prevalent in PD

By Lucy Piper, Senior medwireNews Reporter

Neuropsychiatric symptoms, but not cognitive impairment, are common in early untreated patients with Parkinson’s disease (PD), suggest findings from the multicentre Parkinson’s Progression Markers Initiative (PPMI).

Among 423 of these PD patients studied, rates of multiple neuropsychiatric symptoms were significantly higher than in 196 healthy controls with similar demographic characteristics.

Depression scores on the Geriatric Depression Scale were significantly higher among PD patients and twice as many had clinically significant depression (score ≥5) as controls, at 14.0% versus 7.0%. PD patients also had a higher anxiety burden, with 24.6% scoring above the State-Trait Anxiety Inventory cutoff of 39 for clinically significant state anxiety and 20.1% for trait anxiety, compared with respective rates of 7.7% and 9.7% for controls. And apathy occurred in 17.0% of PD patients versus 5.0% of controls.

Psychosis, which is commonly associated with dopamine replacement therapy, was not significantly more common in PD patients than controls.

“The relatively high rates of [neuropsychiatric symptoms] in early PD have clinical implications”, say researchers Daniel Weintraub (University of Pennsylvania, Philadelphia, USA) and colleagues.

They can have a significant impact on function, quality of life and caregiver burden, they note, stressing “the importance of early, routine screening for a range of highly prevalent [neuropsychiatric symptoms] to initiate optimal treatment.”

Neuropsychiatric symptoms were more likely to occur if patients had the non-tremor dominant motor subtype of PD, severe motor symptoms and if they were non-White.

Cognitive impairment, on the other hand, was not as prevalent. Just 22.0% of PD patient reached the Montreal Cognitive Assessment screening threshold of less than 26 for cognitive impairment, while on a more detailed cognitive test battery, the frequency fell to 8.9% of patients. This is a lower rate than previously reported.

Memory was the most affected cognitive domain and predictors of worse cognitive performance included being older, male and non-White.

Weintraub and team note in Movement Disorders that cognitive performance was not significantly associated with the elevated rates of depression and anxiety seen in the PD patients, rather they suggest a role for PD-related neuropathophysiological changes in key neurotransmitter systems and specific brain regions in their development.

“As the PPMI cohort is followed longitudinally, future analyses can examine the long-term course, predictors, and association with biomarkers for these crucial nonmotor symptoms, which will inform future clinical research and be invaluable for patient education and treatment planning”, concludes the team.

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