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ORIGINAL ARTICLE
Year : 2021  |  Volume : 30  |  Issue : 1  |  Page : 165-174  Table of Contents     

Psychiatric morbidity in patients with idiopathic Parkinson's disease: A cross-sectional study


1 Department of Psychiatry, Post Graduate Institute of Medical Education and Research, Chandigarh, India
2 Department of Neurology, Post Graduate Institute of Medical Education and Research, Chandigarh, India

Date of Submission10-Jan-2021
Date of Acceptance08-May-2021
Date of Web Publication24-Jun-2021

Correspondence Address:
Prof. Sandeep Grover
Department of Psychiatry, Post Graduate Institute of Medical Education and Research, Chandigarh - 160 012
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ipj.ipj_8_21

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   Abstract 


Objective: To evaluate the prevalence of psychiatric comorbidities in patients with idiopathic Parkinson's disease (IPD). Methodology: Two hundred and thirty-nine patients with IPD were evaluated on Mini-International Neuropsychiatric Interview PLUS (MINI-PLUS). In addition, patients found to have depression as per the MINI-PLUS were evaluated on Beck Depression Inventory. Results: One hundred and thirty-five (56.5%) patients had a current psychiatric diagnosis and 59.8% had a lifetime psychiatric diagnosis. As per MINI-PLUS, about two-fifth (39.7%) of patients had suicidality. In 18.8% of patients, suicidality was present in the absence of axis-I psychiatric diagnosis. Among the various psychiatric disorders, the most common disorders included depressive disorders (current: 17.5%; lifetime: 23.8%), anxiety disorders (current: 17.5%; lifetime: 17.5%), and psychotic disorders (current: 11.3%; lifetime: 11.7%). Conclusions: More than half of the patients with Parkinson's disease have psychiatric disorders. High prevalence of psychiatric morbidity calls for close liaison between the neurologist and the psychiatric disorders.

Keywords: Depression, Parkinson's disease, psychiatric disorders, psychosis, quality of life


How to cite this article:
Kumar S, Avasthi A, Modi M, Grover S. Psychiatric morbidity in patients with idiopathic Parkinson's disease: A cross-sectional study. Ind Psychiatry J 2021;30:165-74

How to cite this URL:
Kumar S, Avasthi A, Modi M, Grover S. Psychiatric morbidity in patients with idiopathic Parkinson's disease: A cross-sectional study. Ind Psychiatry J [serial online] 2021 [cited 2021 Aug 1];30:165-74. Available from: https://www.industrialpsychiatry.org/text.asp?2021/30/1/165/319121



Psychiatric comorbidities or neuropsychiatric symptoms are quite frequently reported in patients with Parkinson's disease. The neuropsychiatric syndromes increase the disability, health service utilization, and the risk for hospitalization and decrease the overall quality of life of patients with PD.[1] The commonly reported neuropsychiatric symptoms include depression, anxiety disorders, psychosis, dementia, sleep disorders, and impulse control disorders.[2] The neuropsychiatric syndrome can be due to common etiopathogenesis as that of PD, medications used for management of PD, or as a reaction to the physical illness and its consequences. In most cases, it is more often than not multifactorial in origin.[3] Many studies across the globe have evaluated psychiatric morbidity in patients with PD. Most of these studies have either evaluated only 1 psychiatric disorder, with limited number of studies focusing on the whole range of psychiatric morbidities. Further, most of these studies have relied on the use of screening instruments to report the prevalence of various psychiatric disorders in patients with PD. The available studies have mainly focused on reporting the prevalence and incidence of depression, whereas the data for other disorders are limited. Studies which have evaluated psychosis have in general considered the time frame of last 1 week to last 6 months. Further, these studies have concentrated just on the evaluation of hallucination or have evaluated other psychotic symptoms also along with hallucinations.[2]

Few studies have focused on suicidal behavior in patients with PD, and the prevalence of suicidal ideations/death in patients with PD varies from 22.7% to 30%.[2] Only a limited number of studies are based on the evaluation of patients using various structured interview schedules such as composite international diagnostic interview and structured clinical interview for DSM-IIIR or have used DSM-IV criteria to evaluate the prevalence of depressive disorders.[2]

Very few studies from India have evaluated the prevalence of neuropsychiatric symptoms in patients with PD.[3],[4],[5],[6],[7] Most of these studies have not relied upon the use of structured diagnostic instrument. In this background, this study aimed to evaluate the prevalence of psychiatric comorbidities in patients with idiopathic PD.


   Methodology Top


This cross-sectional study was conducted in the outpatient setting of the department of neurology, of a tertiary care hospital. All the participants were recruited after obtaining written informed consent. Ethics committee of the institute in which the study was conducted approved the study.

The inclusion criteria for the study were diagnosis of idiopathic Parkinson's disease (IPD) as per the Ward and Gibb criteria[8] and age between 35 and 80 years. Patients with intellectual disability, head injury, comorbid serious physical illness, patients severely ill to cooperate with the interview, and patients with symptoms of Parkinsonism due to medications and other neurological and physical illnesses were excluded. The data intake for the study was done during July 2015 to June 2016.

All the patients with clinical diagnosis of IPD, attending the outpatient services (preferably drug naïve-had not received any antiparkinsonian medication), were approached. Consenting patients were assessed on the Ward and Gibb criteria[8] to confirm the diagnosis. The participants were assessed on the Unified Parkinson's Disease Rating Scale (UPDRS)[9] and Hoehn and Yahr (H and Y)[10] staging for PD to rate the severity of the PD. Mini-International Neuropsychiatric Interview PLUS (MINI-PLUS)[11] was used to evaluate the patients for the presence of psychiatric comorbidity. Those patients diagnosed to have depression as per the MINI-PLUS were further assessed for severity of depression using Beck Depression Inventory (BKI) II.[12] Those patients found to have psychiatric morbidity were offered treatment.

The data were analyzed using Statistical Package for Social Sciences, sixteenth edition (SPSS-16; SPSS Inc. Released 2007. SPSS for Windows, Version 16.0. Chicago, SPSS Inc.). Continuous variables were described as mean, standard deviation (SD), and range. Categorical variables were described as frequency and percentages. Comparisons were conducted using Chi-square test and t-test.


   Results Top


The study included 239 patients with IPD. The mean age of the study sample was 59.4 (SD-7.6) years with 30.1% patients aged 65 years or more. The mean number of years of education was 11.1 (SD-2.9) years with nearly equal representation of those educated beyond matric or those educated less than or equal to matric. Males (60%) outnumbered females (40%). Majority of the participants were married (88%) and not on paid employment (63.6%).

The mean age of onset of PD in the study sample was found to be 54.7 (SD-8.2) years, and the mean duration of PD was 63.3 (SD-50) months. Other clinical details are given in [Table 1].
Table 1: Clinical profile of Parkinson's disease (n=239)

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Psychiatric morbidity

Out of the 239 patients, 135 (56.5%) patients had a current psychiatric diagnosis and 59.8% had a lifetime psychiatric diagnosis as per MINI-PLUS [Table 2]. As per MINI-PLUS, about two-fifth (39.7%) of patients had suicidality. In 18.8% of patients, suicidality was present in the absence of axis-I psychiatric diagnosis [Table 2].
Table 2: Psychiatric illness as assessed on Mini-International Neuropsychiatric Interview Plus (n=239)

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The mean BDI score for patients with major depressive disorder was 45.9 (SD-5.2), with almost all patients (22 out of 23) having BDI score in the range of severe depression (total score: 29–63). The mean BDI score for patients with dysthymia was 27.0 (SD-1.6), with again almost all of such patients (18 out of 19) having BDI score in the range of moderate depression (total score: 20–28).

When the association of onset of psychiatric disorders and onset of PD was evaluated, in 62 patients (about half, i.e., 48.8% of the patients with lifetime axis-I psychiatric diagnosis other than tobacco dependence), psychiatric symptoms preceded the onset of PD. In more than one-fourth (29.1%), symptoms of PD preceded the onset of psychiatric disorder, and in 22% of patients, both the disorders started almost together.

The mean age of onset of psychiatric illness was 24.8 (SD-25.7) years and the mean duration of treatment for IPD at the time of assessment was 48.9 (SD-105.2) weeks. Family history of mental illness was seen 14.2% of cases.

Relationship of psychiatric morbidity with other variables

Those with current and lifetime axis-I psychiatric disorder were compared with those without current and lifetime axis-I psychiatric disorder, respectively, to study the factors associated with development of psychiatric disorders in patients with PD; significant differences were noted for certain demographic and clinical factors [Table 3] and [Table 4].
Table 3: Comparison of demographic and clinical profile of those without (Group I) and with (Group II) current psychiatric illness

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Table 4: Comparison of demographic and clinical profile of those without (Group I) and with (Group II) lifetime psychiatric illness

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Relationship of depression with other variables is shown in [Table 5] and [Table 6].
Table 5: Comparison of participants with current depression (major depression plus dysthymia) (Group I) and without current depression (Group II) (n=239)

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Table 6: Comparison of participants with lifetime depression (major depression, dysthymia) (Group I) and without lifetime depression (Group II)

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Relationship of psychosis with other variables

When those with psychosis were compared with those without psychosis, those with psychosis had lower age of onset (P = 0.032*), longer duration of illness (P < 0.001***), higher scores on the UPDRS domains of mentation, behavior and mood (P = 0.001***), activities of daily living (P < 0.001***), and motor examination and total of these 3 domains (P = 0.001***). Higher proportion of those with psychosis had severe to complete disability due to dyskinesia (P = 0.038*), gastrointestinal symptoms (P = 0.037*), sleep disturbances (P = 0.044*), orthostatic (P = 0.004**), and sleep disturbances (P = 0.044*).

Relationship of anxiety disorders with other variables

When those with anxiety disorder were compared with those without anxiety disorder, higher proportion of those with anxiety disorder had diabetes mellitus (P = 0.01**), family history of PD (P = 0.007**), gastrointestinal symptoms (P = 0.019*), and more than 2.5 stages (P < 0.001***) as per the modified H and Y staging.

Those with anxiety disorder had higher scores on the UPDRS domains of mentation, behavior and mood (P < 0.001***), activities of daily living (P = 0.001***), motor examination (P < 0.001***), and total of these 3 domains (P < 0.001***). Lower proportion of those with anxiety disorder had predictable “off” periods (P = 0.037*).


   Discussion Top


In the present study, 17.5% of patients had current diagnosis of a depressive disorder and 23.8% of patients fulfilled the lifetime diagnosis of depressive disorder. In terms of type of depressive disorder, major depressive disorder was seen in 9.6% of patients and lifetime diagnosis of major depressive disorder was seen in 15.9% of patients. Diagnosis of dysthymia was made in 7.9% of cases. Existing literature suggest the prevalence of major depression in patients with PD to vary from 2.7% to 55.6%[13],[14],[15],[16],[17],[18],[19],[20],[21] and 2.2% to 31.3%[13],[22] for dysthymia. Overall, the prevalence of clinically significant depressive features has varied from 2.7% to 89%.[13],[21],[23] Findings of the present study are in the reported range for all the types of depressive disorders. Overall, in the present study, 25.4% had a current depressive disorder (major depressive disorder or dysthymia).

Existing literature does not support the association of depression in patients with PD with any of the sociodemographic variables except for higher prevalence of depression in females.[24],[25],[26] However, majority of the studies have not reported female gender to be a risk factor for depression in patients with PD. Findings of the present study too support the same.[14],[27],[28],[29]

In terms of clinical factors, literature suggest the association of depression with advanced/more severe disease,[25],[30] longer duration of illness,[30] early and late stage of disease,[15] motor disability,[31] bradykinesia,[32],[33] dystonia,[34] presence of tremor,[35] presence of motor fluctuations,[30],[31] more evidence of atypical parkinsonism,[31] gait and balance impairment,[32] younger age,[31] and higher daily doses of levodopa.[30],[31] Findings of the present study also support many of these associations. In the present study, depression was associated with significantly lower age of onset, longer duration of illness, had higher severity of illness as assessed by UPDRS, and dyskinesia for longer duration in a day. Further higher proportion of those with depression had severe to complete disability due to dyskinesia, painful dyskinesia, dystonia, gastrointestinal symptoms, sleep disturbances, and orthostasis. In addition, higher proportion of them had disease severity of more than 2.5 as per the modified H and Y staging. However, lower percentage of them had “off” periods lasting for 50%–75% of the day. No relationship was noted between depression and medications used for the treatment of PD. In terms of impact of depression, studies have consistently shown deterioration of scores on activities of daily living.[13],[14],[31] Findings of the present study also suggest that the presence of any kind of depression at the time of assessment is associated with higher impairment in activities of daily living. Taken together, the findings of the prevalence of depression and severity of the same suggest that there is a need to routinely screen patients of PD for depression and those found to have depression must be treated adequately to improve the overall outcome of the disorder. If it is not possible to screen all the patients of PD for depression, at least those at high risk must be screened routinely using screening questionnaire and those found positive in the screening questionnaires must be evaluated further to confirm the diagnosis. It is also important to emphasize to the treating neurologist that if depression is not treated adequately, it can lead to higher level of impairment in activities of daily living.

In the present study, among the other psychiatric disorders, the single most common diagnosis was that of psychotic disorders, seen in 11.3% of patients at the time of assessment and 11.7% of patients in the lifetime. The prevalence of psychosis (or visual hallucinations) in the existing literature has varied from 15.8% to 75%.[2],[36],[37] However, it is important to note that many of these studies have evaluated only the prevalence of certain symptoms such as visual hallucination rather than making a syndromal diagnosis. The slightly lower prevalence than that reported in the literature in the present study could be due to reliance on making a syndromal diagnosis, rather than focusing on symptoms of psychosis per se. In terms of risk factors, in the present study, those with psychosis had lower age of onset, longer duration of illness, and higher severity of illness as per the total UPDRS score. In addition, higher proportion of those with psychosis had severe to complete dyskinesia, gastrointestinal symptoms, sleep disturbances, orthostasis, clinical insomnia, and daytime sleepiness. When the relationship of psychosis and antiparkinsonian agents was evaluated, in two-third of the cases (64.9%), psychosis was associated with use of antiparkinsonian medications. Existing literature from developed countries have also identified similar risk factors.[38]

When all the anxiety disorders were taken together, the prevalence of anxiety disorders was 17.6%. Studies from other parts of the world have also reported prevalence of anxiety disorders to vary from 19.8% to 67%.[39] Findings of the present study are close to the lower level of prevalence reported in literature, and this could be possibly due to evaluation of anxiety disorder based on the structured interview in the present study. The most common anxiety disorders in patients with PD are panic disorder,[2] generalized anxiety disorder, and social phobia.[2],[40] In the present study too, panic disorder (seen in 8.8% of cases) was the most common anxiety disorder seen in patients with PD, followed by generalized anxiety disorder (3.3%) and obsessive–compulsive disorder (3.3%). Only few patients had comorbid agoraphobia (2.9%). Although few studies suggest a correlation of higher level of anxiety with left-sided lesions, most studies have shown no relationship between severity of motor symptoms and levels of anxiety.[25],[41] In the present study too, higher proportion of those with anxiety disorder had disease severity of more than 2.5 as per the modified H and Y staging.

Other risk factors reported for anxiety disorder/symptoms in patients with PD include female gender,[28] younger age,[28] young onset PD,[40] more depressive symptoms,[28] worst sleep quality,[28] severity of PD,[41] postural instability,[41] gait dysfunction,[41] higher rates of motor fluctuations,[40] morning dystonia,[41] symptom clustering, and experience of dyskinesias.[41] Findings of the present study also support some of these associations. In the present study, higher proportion of those with anxiety disorder had higher income, had diabetes mellitus, family history of PD, had dyskinesia for more than 50% of the day, and gastrointestinal symptoms. Further, it was seen that those with anxiety disorder had higher severity of illness as per the assessment on UPDRS and more impairment in activities of daily living.

The present study has certain limitations. The study sample was recruited from the patients attending a neurology clinic. Hence, the study cannot be generalized to the patients living in the community. The study involved cross-sectional evaluation, very few patients who were drug naïve, and the study did not evaluate the phenomenology of various psychiatric disorders. Hence, there is a need for more extensive and longitudinal studies to evaluate patients attending the clinics and those living in the community.


   Conclusions Top


The present study suggests that patients with IPD have high prevalence of psychiatric morbidity. Considering the prevalence of psychiatric morbidity, there is a need for active collaboration between the neurologists and psychiatrists to improve the outcome of patients with PD. Whenever a collaborative functioning cannot be ensured, the treating neurologist should use appropriate screening measures to evaluate the possibilities of these comorbidities. When a comorbid disorder is suspected, a suitable referral consultation must be sought.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]



 

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