Depression is a common comorbid condition in Parkinson’s disease (PD) and a major contributor to poor quality of life and disability. However, depression can be difficult to assess in patients with PD due to overlapping symptoms and difficulties in the assessment of depression in cognitively impaired patients. As several rating scales have been used to assess depression in PD (dPD), the Movement Disorder Society commissioned a task force to assess their clinimetric properties and make clinical recommendations regarding their use.
A systematic literature review was conducted to explore the use of depression scales in PD and determine which scales should be selected for this review. The scales reviewed were the Beck Depression Inventory (BDI), Hamilton Depression Scale (Ham-D), Hospital Anxiety and Depression Scale (HADS), Zung Self-Rating Depression Scale (SDS), Geriatric Depression Scale (GDS), Montgomery-Asberg Depression Rating Scale (MADRS), Unified Parkinson’s Disease Rating Scale (UPDRS) Part I, Cornell Scale for the Assessment of Depression in Dementia (CSDD), and the Center for Epidemiologic Studies Depression Scale (CES-D). Seven clinical researchers with clinical and research experience in the assessment of dPD were assigned to review the scales using a structured format.
The most appropriate scale is dependent on the clinical or research goal. However, observer-rated scales are preferred if the study or clinical situation permits. For screening purposes, the HAM-D, BDI, HADS, MADRS, and GDS are valid in dPD. The CES-D and CSDD are alternative instruments that need validation in dPD. For measurement of severity of depressive symptoms, the Ham-D, MADRS, BDI, and SDS scales are recommended. Further studies are needed to validate the CSDD, which could be particularly useful for the assessment of severity of dPD in patients with comorbid dementia.
To account for overlapping motor and nonmotor symptoms of depression, adjusted instrument cutoff scores may be needed for dPD, and scales to assess severity of motor symptoms (e.g., UPDRS) should also be included to help adjust for confounding factors. The HADS and the GDS include limited motor symptom assessment and may, therefore, be most useful in rating depression severity across a range of PD severity; however, these scales appear insensitive in severe depression. The complex and time-consuming task of developing a new scale to measure depression specifically for patients with PD is currently not warranted.
Depressive symptoms commonly occur in Parkinson’s disease (PD), affecting approximately 40% of patients in cross-sectional studies. Depressive symptoms have also been recognized to be a major determinant of health-related quality of life in PD, and can affect functional ability, cognitive function, and caregiver quality of life. It is, therefore, important to recognize and assess depressive symptoms in patients with PD adequately. The gold standard for the diagnosis of depressive disorder at present are the criteria of the Diagnostic and Statistical Manual, Fourth Edition (DSM-IV), of the American Psychiatric Association. However, in clinical practice and research studies, particularly in epidemiological studies, surveys, and treatment trials measuring severity of depressive symptoms, use of DSM-IV criteria often is not feasible or useful. Several rating scales for screening and/or assessment of severity of depression are available and have been used widely to assess depression in patients with and without PD.
However, there are several methodological difficulties in assessing depressive symptoms in PD, and it is unclear which scales are suitable for the assessment of depression in this patient group. The Movement Disorder Society (MDS) Task Force on Rating Scales for Parkinson’s Disease therefore commissioned a critique of existing scales as applied to Parkinson’s disease and to place them in a clinical and clinimetric context, similar to MDS reviews of the Unified Parkinson’s Disease Rating Scale (UPDRS)7 and Hoehn & Yahr staging system.8 The purpose of this effort was the evaluation of all commonly used or appropriate rating scales for depression in PD (dPD) and to make recommendations on the utilization of specific scales and their need for modifications or replacement in this population.
The DSM-IV criteria for depressive disorder are the current gold standard against which such scales are compared. However, the use of these criteria (or other criteria such as the those of the International Classification of Diseases [ICD-10]) in PD has shortfalls, and recommendations have been made to revise the DSM-IV criteria for depressive disorder when applied to PD to overcome these methodological difficulties.9 Although a discussion of the validity of these criteria for depression in patients with PD is not the subject of this manuscript, these problems and their impact on the use of scales to assess of presence and severity of depression in patients with PD are recognized and discussed.
1. Anette Schrag MD, PhD,
2. Paolo Barone MD,
3. Richard G. Brown PhD,
4. Albert F.G. Leentjens MD, PhD,
5. William M. McDonald MD,
6. Sergio Starkstein MD,
7. Daniel Weintraub MD,
8. Werner Poewe MD,
9. Olivier Rascol MD,
10. Cristina Sampaio MD,
11. Glenn T. Stebbins PhD,
12. Christopher G. Goetz MD