Parkinson’s disease (PD) is a disease that affects movement
and motor capabilities. PD also has a
variety of non-motor symptoms, of which anxiety and depression are especially
common. These psychiatric disorders are
referred to by healthcare professionals as affective, or mood, disorders. It is estimated that 25-75% of patients with
PD will experience significant symptoms of anxiety or depression at some point
during their illness [1, 2].
Depression is a common mental health issue. The National Health and Nutrition Examination
Survey, 2009–2012 reported that 7.6% of Americans aged 12 and over,
experienced moderate or severe depressive symptoms, when polled about mood
during the last two weeks [3].
Depression can be more difficult to identify in patients
with PD. Lack of energy or inability to
accomplish daily activities may be attributed erroneously to the motor symptoms
of PD, rather than to a depressive episode.
Some of the common signs and symptoms of depression are:
Persistent sad, anxious, or “empty” mood
Feelings of hopelessness or pessimism
Irritability
Feelings of purposelessness
Loss of interest or pleasure in hobbies and
activities
Decreased energy or fatigue
Excessive slowness in daily activities
Difficulty in concentrating, remembering, or making
decisions
Difficulty in falling asleep, or early morning
awakening
Appetite and/or weight changes [4]
Doctors used to think that depression in patients with
PD patients was an emotional response to the diagnosis of their disease. A newer theory is that the disease itself is
the cause of these mood issues [5-7].
Depression is a result of chemical imbalances in the
brain [8]. There have been significant
successes in mental health treatment using drugs such as fluoxetine (Prozac) or
bupropion (Wellbutrin). These drugs are
classified as selective serotonin reuptake inhibitors (SSRIs), which means that
they block the reabsorption of serotonin—a chemical in the brain that is linked
to mood stability. By allowing this neurochemical
to remain in the brain for longer, the mood benefits of these drugs are
sustained.
Anxiety—like depression—is common in PD patients [5,
6, 9]. Along with SSRIs, which can
produce anti-anxiety benefits, another class of drugs exists for treating
generalized anxiety disorders and panic attacks: serotonin-norepinephrine
reuptake inhibitors (SNRIs). These drugs
block the reabsorption of these two neurotransmitters and should be used in
preference to benzodiazepines, which have more side effects and can be
habit-forming. SSRIs and SNRIs stabilize
mood, and in many cases can provide satisfactory relief from depression and
anxiety. Psychological counselling, in addition to a drug therapy regimen, is
optimal [10].
It may take up to three months or so after initiation
of an anti-depressant before there is a reduction of symptoms [10, 11]. Patients must allow time for the medication
to work and for most patients, treatment should continue for at least a year
after it begins to help.
In addition to medication, exercise is effective [12-14]
in the treatment of depression. Outdoor
exercise is particularly helpful as sunlight helps stimulate the brain to
produce serotonin. Social interaction is
also beneficial for mood and stimulates the brain [15].
Patients may not recognize that they are
depressed. It is helpful for a spouse,
partner, or close friend to accompany patients to follow-up appointments, as
they can help answer questions on mood changes and level of social activity.
For patients taking carbidopa/levodopa (Sinemet), complications
can arise after months or years of treatment.
There may be response fluctuations, either “wearing off” effect or “on/off”
periods. A “wearing off” effect is when
a patient is aware of a loss of symptomatic benefit of Sinemet before the next
scheduled dose. “On/off” periods are
response fluctuations marked by rapidly cycling response changes—shifting
between normal, under-medicated, and over-medicated states without any
relationship to the timing of doses. Depression
and anxiety may occur in patients with these complications, particularly when a
patient is in an “off” stage. While treating the on/off motor phenomena can be difficult,
the medical treatment of depression and anxiety should be the same as in any
patient with a similar mood complaint.
Patients with PD should see a neurologist regularly so
that their symptoms are managed optimally.
Symptoms of depression and anxiety —similar to motor symptoms— should
also be discussed.
References
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A, Gallo JJ, Pontone GM: Systematic review of factors associated with
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Symptomatology and markers of anxiety disorders in Parkinson's disease: a
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LA, Brody DJ: Depression in the U.S. household population, 2009–2012. NCHS data
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13. Tuon
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