The Complexity of Comorbid Parkinson’s Disease and Schizophrenia

It is well known within the medical community that Parkinson’s Disease (PD) is a neurological disorder commonly associated with low levels of dopamine (DA) within the brain. Currently, the most popular treatment for PD is L-DOPA, which is a dopamine precursor meant to increase dopamine activity within the brain, thereby easing PD symptoms.

However, PD treatments that are prescribed in an effort to solely increase dopamine activity puts Parkinson’s patients at risk of developing mild Schizophrenic symptoms. Put simply, Schizophrenia is a neurological disorder that is caused by excessive DA activity, and thus PD treatments such as L-DOPA can induce physiological issues related to Schizophrenia. However, the threshold that defines “excessive dopamine function” is not generalizable to each individual, and must be analyzed on an inter-individual basis in order to increase individual L-DOPA dosage accuracy and decrease side effect risks. Nonetheless, such inter-individual analysis is currently difficult, and highly effective treatments that are able to accommodate both Schizophrenia and Parkinson’s related symptoms are little to none. Regardless, more effective treatments for both disorders must be investigated and introduced to the market in order to better serve the affected population.

To further illustrate my point, a case report published by Lan and colleagues in 2011 on a patient comorbid with Parkinson’s Disease and Schizophrenia clearly shows the desolate conditions under which such patients operate due to the treatment dilemma I previously examined. The patient, referred to by the authors as Mr. A, was able to finally stabilize his symptoms after years of ineffective treatments and settled on a daily routine of different doses of four different drugs. However, this does not discount the fact that Mr. A and his family had to suffer tremendous burdens during the many years that it took in order for physicians to find a regimen that would balance Mr. A’s symptoms. More alarming, though, is the fact that though this specific prescription of drugs worked out for the patient in this study, there is no guarantee that such a routine is generalizable to current and future patients that are comorbid for Parkinson’s and Schizophrenia.

Even if one specific prescription of drugs work out for the patient, there is no guarantee that such a routine is generalizable to current and future patients that are comorbid for Parkinson’s and Schizophrenia. Undoubtedly, the significance of finding better, more effective treatments that can ease Parkinson’s and Schizophrenic symptoms is immense. Currently, the main drugs, such as L-DOPA, that are being used to treat people affected by Parkinson’s are inefficient in ensuring that there are no risks for developing Schizophrenic symptoms or vice versa. Furthermore, the lack of treatments available for those who are comorbid for both Parkinson’s and Schizophrenia is more alarming and raises the question of whether the generalizability of current treatments are also overlooked. Certainly, we should not simply settle for our current treatments which simply mitigate symptoms, but be more meticulous in our continued search for more effective treatment options.

By Jennifer Bi '18 | Staff Writer


Lan, Su, Chen, & Bai. (2011). Treatment dilemma in comorbidity of schizophrenia and idiopathic Parkinson’s disease. General Hospital Psychiatry, 33(4), 411.e3-411.e5.