Description/Etiology
Parkinson’s disease (PD) is a progressive neurodegenerative disorder related to a deficiency of the neurotransmitter
dopamine in the brain structures that control voluntary movement. Presentation of this chronic debilitating
condition is insidious, usually begins unilaterally with mild symptoms, and eventually manifests bilaterally with
increasingly severe symptoms. PD is characterized by a variable combination of tremor, bradykinesia, rigidity, and
postural instability. Advancing disease erodes all functional abilities, causing autonomic dysfunction, musculoskeletal
deformities, sensory symptoms, sleep disturbances, dermatological problems, and psychiatric symptoms (for more
information, see Quick Lesson About…Parkinson’s Disease ).
Depression is a common complication of PD that negatively influences patient and caregiver quality of life (QOL),
and is associated with a worsening of disease symptoms, a more rapid decline in health status, high psychiatric
comorbidity, and increased caregiver burden. Symptoms of depression in patients with PD tend to occur at two
time points: near the time of diagnosis and later in the disease as disability and impairment increases. Depression in
early PD may be associated with the emotional adjustment to having a chronic, progressive disease, while depression
late in PD is likely related to biochemical or degenerative changes related to PD (e.g., a deficiency in dopamine,
serotonergic system dysfunction).
It is thought that most PD patients develop depressive symptoms of some duration, and that depression is associated
with the disease. Depression in PD is similar to that in the general population; but with a higher incidence of feelings
of failure, anxiety, and suicide , and a decreased incidence of feelings of guilt and self-blame. Many patients with PD
find secondary symptoms, including depression, to be more troublesome than the characteristic motor symptoms.
Diagnosis of depression in PD is based on presenting psychological symptoms; patients with PD may be diagnosed
with major depressive disorder, seasonal affective disorder, dysthymic disorder, or minor depression. Assessment for
and diagnosis of depression in patients with PD may be complicated by the fact that some symptoms of PD overlap
with those of depression (e.g., insomnia, fatigue, difficulty concentrating).
Although nothing prevents PD progression, pharmacotherapy can control symptoms, maintain patient
independence, and slow progression. Treatment for depression in PD has been shown to improve not only
depressive symptoms, but motor dysfunction as well. Psychotherapy (e.g., cognitive-behavioral therapy [CBT])
may improve depressive symptoms. Pharmacologic treatment (e.g., with antidepressant agents) is common, and
electroconvulsive treatment (ECT) may be ordered for patients who have severe depression.
Facts and Figures
Depression is among the most common non-motor symptoms in patients with PD, affecting over 50% of patients
with the disease. An estimated 17% of patients with PD have major depression, 22% have minor depression, and
13% have dysthymic disorder. Depression commonly coexists with anxiety in patients with PD.
Risk Factors
Risk factors for depression in PD are thought to include younger age of PD onset, longer disease duration, more
severe symptomatology, cognitive impairment, pain, ineffective coping strategies, lack of social support, history of
depression, and coexisting dementia. Depression is more common in PD patients with akinetic-rigid PD compared
with tremor-dominant PD.
Signs and Symptoms/Clinical Presentation
Symptoms of depression are frequently difficult to detect in patients with PD. Presentation of depression associated
with PD may include apathy, fatigue, anhedonia (i.e., lack of pleasure in previously pleasurable activities), significant
weight change, sleep disorders, anorexia, loss of libido, reduced memory, lack of energy, and suicidal ideation .
Assessment
› Laboratory Tests That May Be Ordered
• There are no laboratory tests diagnostic of depression in patients with PD
› Other Diagnostic Tests/Studies
• The Montgomery Åsberg Depression Rating Scale, Hamilton Depression Rating Scale, the Beck Depression Inventory-I, and the World Health
Organization (WHO)-Five Well-being Index can aid in the diagnosis of depression
Treatment Goals
› Promote Optimum Physiologic and Emotional Status and Educate
• Assess patient’s anxiety level, coping ability, and level of depression, and monitor for suicidal ideation; institute suicide precautions , if appropriate.
Provide emotional support, educate, and encourage discussion about the incidence of depression in patients with PD, potential complications, treatment
option risks and benefits, and individualized prognosis
• Request referral to a mental health clinician (e.g., for evaluation, diagnosis, and counseling with CBT) if one is not already part of the treatment team
• Administer prescribed antidepressants, such as SSRIs (e.g., sertraline) or TCAs (e.g., amitriptyline, nortriptyline); medications for sleep disturbance may be
ordered
• Assess for knowledge deficits in the patient and/or family about anti-Parkinson medications and treatment options (for details, see the Quick Lesson
referenced above)
• Request referral to physical, occupational, and speech therapies to treat impaired physical abilities, and educate about modification in daily routines for
improved safety and functionality in the home environment
• Encourage moderate exercise to decrease symptoms; all clinicians should encourage the patient and family to maintain a positive outlook, and reinforce that
even decreased levels of exercise and activity are beneficial
• Encourage patient to perform as many daily tasks as he or she can independently, and to participate in support groups and other social activities
– Request referral to a social worker, if appropriate, for identification of local resources for in-home services, support groups, outpatient physical therapy,
and transportation
• Follow facility pre- and posttreatment protocols if patient becomes a candidate for ECT; reinforce pre- and posttreatment education and verify completion
of facility informed consent documents
Food for Thought
› Although individual studies on the effects of antidepressants on depression in patients with PD have produced positive results, authors of a 2011 systematic
review of 20 randomized trials comparing antidepressants to placebo in 1,137 adults with neurological disorders found no significant differences in patients
with PD (Price et al., 2011)
› In addition to potentially helping to alleviate depression in patients with PD, tricyclic antidepressants may also improve sialorrhea (i.e., excessive secretion of
saliva), a common complication of PD, because of their anticholinergic side effects
Red Flags
› SSRIs may, in some cases, worsen the motor symptoms of PD
What Do I Need to Tell the Patient/Patient’s Family?
› Discuss the benefits of maintaining physical and mental health, increasing independence where possible, and becoming educated on PD
› Encourage joining one or more local support groups for stress reduction for patient and family, social interaction, family care services, and disease education
› Emphasize the importance of continued medical surveillance to screen for side effects of the medication regimen, and adjust the treatment regimen for
increasing disability