Impulse control disorder symptoms also commonly found in Parkinson disease patients treated with dopamine agonists.
Daniel Weintraub, MD
The neural substrates often associated with Parkinson disease dementia could also predispose patients to the development of compulsive behaviors, according to new research.
A team, led by Daniel Weintraub, MD, assistant professor of psychiatry, University of Pennsylvania, conducted a multicenter, cross-sectional, observational, Spanish nationwide study, which included 529 individuals—85 with Parkinson disease dementia and with Parkinson disease without dementia.
Impulse control disorder (ICD) symptoms were found to be more common in patients with Parkinson who were frequently treated with dopamine agonists and had comorbid dementia.
The new data showed that dopamine agonist therapy use is both common and similar in Parkinson disease with dementia (78.8%) and without dementia (82.9%).
However, ICD symptoms occurred in 23.5% (n = 20) of those with comorbid dementia compared to 13.3% (n = 59) in those without (P = .02), and both hobbyism‐punding (Parkinson with dementia: 32.9%, n = 28; Parkinson without dementia: 10.6%, n = 47; P <.001) and dopaminergic medication abuse (Parkinson with dementia: 8.2%, n = 7; Parkinson without dementia: 3.2%, n = 14; P = .03) were more common in the group with dementia.
In addition to a higher prevalence of ICD and related behaviors in patients with comorbid dementia, the severity of these behaviors—assessed by the Scale for Evaluation of Neuropsychiatric Disorders in PD (SEND-PD)—were also significantly different between groups.
Those with dementia had mean SEND-PD scores of 0.5 ±0.8 for hobbyism-punding, 0.4 ±0.7 for ICDs, and 0.2±0.6 for dopaminergic drug abuse, compared to scores of 0.14 ±0.4 (P <.001), 0.2 ±0.5 (P = .01), and 0.03 ±0.2 (P = .02), respectively, for the group without dementia.
The investigators noted that if the dementia-underpinning neural substrates influence the development of compulsive behaviors in this population, it may be related to dementia-associated monoaminergic deficits, and changes in neural pathways, or cognitive impairments.
“Regardless, the findings of this study demonstrate that significant cognitive impairment may be a risk factor for development of ICDs and related behaviors when biases in prescription patterns are accounted for, which is of clinical significance and provides additional justification for using dopamine agonists cautiously in patients with significant cognitive impairment,” the authors wrote.
Those who had Parkinson with comorbid dementia had a higher total levodopa equivalent daily dose (811.9 ±479.4) compared to those without comorbid dementia (622.5 ±427.2; P <.001), despite their dopamine agonist levodopa equivalent daily doses not being significantly different (Parkinson with dementia: 195.9 ±163.6; Parkinson without dementia: 211.7 ±151.0; P = .19).
The investigators additionally noted that the association between dementia and elevated rates of ICD symptoms and related behaviors has not been, to their knowledge, previously reported. They cited that this may be due to the fact that dopamine agonists are not often prescribed to the elderly patient population or those with dementia because of the possible adverse effects.
“It is important to note that higher total levodopa exposure may also have contributed to the higher frequency of ICD behaviors in the Parkinson with dementia group, consistent with previous research from the DOMINION study that suggested higher levodopa exposure was associated with ICDs in Parkinson,” the authors wrote.