Parkinson's disease and depression
Depression is a condition which, like other mental disorders, cannot be diagnosed simply by objective measures. The diagnosis is even more difficult in Parkinson's disease (PD) since many of the symptoms of PD itself — slow movements, blank facial expressions, sleep disturbances, stooped posture and cognitive impairments — mimic those of depression.
Compounding the problem of overlapping symptoms are the varying methodologies, selection criteria and definitions of depression that researchers use. Together these factors could account for the wide differences in prevalence that have been reported in numerous studies of PD patients over the past few years.
Studies have suggested clinical depression is related to changed levels of serotonin in the brain. Some doctors have discovered that the general slowing down of mental capacity, brought about by age as well as the effects of PD, can be misinterpreted as dementia or depression. It has been said that 'if you give a Parkinson's patient time to answer a question, they will answer. If you give an Alzheimer's patient time to answer a question, they will forget the question'.
It is not known definitely whether depression is more prevalent among early-onset (i.e. before age 65) patients than older-onset PD. A study carried out in Baltimore in the USA attempted to find out if any correlation exists between depression and age of onset of PD. Researchers studied 105 patients and assessed their symptoms using the Diagnostic and Statistical Manual of Mental Disorders 3rd edition (DSM-III) to classify patients as having major, minor or no depression.
The authors found that although the 2 groups varied little in the incidence of minor depression, the early-onset group showed a much higher prevalence of major depression. One might assume that duration of disease would be a factor here, as those who had been diagnosed early could have had PD for a longer time. However, it was discovered that the length of time that a patient had PD was not significant. It was found that those who had been diagnosed early suffered different clinical problems from the late-onset group and concluded that this suggested a biochemical factor played a role in PD-related depression.
It is possible that higher levels of depression in younger-onset PD would reflect a reaction to being diagnosed with a chronic and degenerative condition at a period in life when they could expect to be actively involved in family, work and leisure activities.
One study has pointed to the low metabolism rates that are evident in depressed patients (Mayberg, Family Practice News, 30 June 1990). Other studies in the UK suggest a possible genetic link between PD and depression. Studies are continuing to investigate just why it is that PD patients have a high level of depression.
Characteristics specific to PD
It is thought that a 'disease specific' depression may exist with PD. Evidence for this theory has arisen from comparative studies between depressed people with PD and depressed people with other chronic disabilities. Depression in people with PD tends to be more severe in comparison with other disabled groups when matched for functional disability.
The good news is that some of the medications used in the treatment of PD have antidepressant qualities.
Whatever the studies conclude, there are suggestions available from people with PD on how to avoid depression. A large number state that belonging to a support group and having family support is very important in keeping up a healthy psychological balance. They also report that positive thinking, daily exercise and a healthy diet contribute to mental health and that these factors combined will help anyone with PD to stay active, healthy and positive.
Treatments for depression
Medication
Treatment of depression in PD can be a difficult exercise, as many of the antidepressant medications interact with the anti-parkinsonian medications, producing negative side effects.
What to avoid
Prozac: may cause serious problems when combined with Eldepryl. Prozac can worsen mobility.
Parnate and Nardil (MAO Inhibitors): when combined with Sinemet can produce serious side effects as Parnate and Nardil increase the effect of Sinemet.
Recommended
Tricyclic antidepressants (e.g. amitriptyline, nortriptyline and imipramine): this family of medication has been found to be effective in the treatment of depression in PD. Plus, some actually reduce the symptoms of PD (e.g. imipramine may improve rigidity and tremor).
Side effects of tricyclic antidepressants
Common: headache, dry mouth, drowsiness, nausea, insomnia, indigestion, constipation/ diarrhoea.
Uncommon: hallucinations, nightmares, vomiting, blurred vision, confusion, dizziness and difficulty in urination.
Electro Convulsive Therapy (ECT)
ECT ('shock therapy' as it was previously known) is only used as a last resort treatment, when a person is so depressed that they are not eating or sleeping. The depression is then considered to be 'life threatening', and if medication has been ineffective a course of ECT will be trialled. (ECT is generally given 6-8 times over a period of weeks as one session is not effective.)
Interestingly, ECT has been found to provide relief for the symptoms of PD. This relief is short-lived, though, lasting only days or a few weeks. ECT generally causes a person to experience some short-term memory loss for a period of time after treatment. This is more so for elderly people. However, despite its limitations, ECT is an extremely effective treatment for depression and may well be life-saving in some cases.
Counselling
Counselling is a very important in treatment of depression. Although medication and ECT produce positive effects, talking the situation over with someone can be very important and can be a useful addition to the 'biological' treatments.
Knowing that an understanding person is prepared to listen to their concerns can often give people the motivation to 'keep going'. A counsellor can help clarify the situation, provide information to increase options in problem solving and, if wished, can assist the family to understand what Parkinson's is and how it affects both the person with Parkinson's and the other members of the family.
Tips for dealing with depression
- Allow yourself to experience the pain and reality of the situation.
- Identify your emotions.
- Know yourself. What triggers your depression?
- Do not be ashamed to cry.
- Engage in some exercise on a regular basis.
- Be aware that depression is more common on rainy days, in winter and when confined.
- A well-balanced diet can be helpful.
- Identify people that you can turn to for support.
- Plan to do something enjoyable for days when you are feeling down.
- See a doctor and a counsellor.
- Stay involved with others and remain active.
Last Reviewed: 23 July 2002
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