"Panic attacks" in Parkinson's disease. A long-term complication of levodopa therapy

A series of 31 Parkinson's disease (PD) patients suffering from panic attacks (PA), late in the evolution of their disease, was analyzed from a group of 131 levodopa-treated PD patients. We found that many of motor, sensory, and vegetative symptoms, previously described as complicating phenomena in PD, constituted some of the symptoms of panic disorders. Comparing PA series with the series of PD patients who did not complain of PA, we discovered a clear-cut relationship of PA with the presence of standing/gait troubles (p < 0.001), depression (p < 0.001), and dyskinesias/fluctuations (p < 0.001). The patients of the PA series also presented a more precocious age of PD onset, were put on levodopa therapy earlier, and needed to be treated with higher doses of levodopa than the patients without PA. Finally, we hypothesize that PA could be considered to be a sort of abstinence syndrome from levodopa, because they appears mostly (90.3%) in the OFF phase of fluctuations, and are relieved administering new doses of levodopa or dopaminergic agonists. Nevertheless, we suggest PA are not directly related to the pharmacological properties of levodopa, but to alterations of the noradrenergic systems in the CNS.