Comparison of Essential Tremor vs. Parkinson’s Disease: Social Phobia & Depression

Conclusion first:  According to the research cited below, medical practitioners, as well as the rest of us, should view essential tremor (ET) and Parkinson’s disease (PD) not merely as neurological conditions but as neuropsychiatric ones.  I suppose many of us already do this in practice, but for the first few years after I was diagnosed with PD I believed, and told everyone, that I had a neurological disease (or I went with the term “movement disorder”).  This was true even when I recognized and discussed with my doctor that I was experiencing a lot of anxiety.  I viewed anxiety as ancillary, a side show, and not part of the main attraction.

A recent research report from Latvia (“Depression and social phobia in essential tremor and Parkinson’s disease“) arrived at this conclusion, after the researchers compared 40 patients with essential tremor to 39 patients with Parkinson’s disease, and both groups to 35 healthy controls.  All participants received neurological evaluations; completed a battery of written tests that looked at depression, social anxiety, and social phobia; and were clinically interviewed.

While individuals in all three groups displayed social anxiety and depression to some degree, these are some of the standout results:

Essential Tremor (ET)

• ET patients were far more worried about what to say in social situations than people in the other two groups.
• ET patients were more nervous if they had to speak with someone in authority.
• In terms of depression, ET patients were most critical of themselves, and registered the greatest loss of interest in sex.

Parkinson’s Disease (PD)

• PD patients felt more anxiety than people in the other two groups when they had to interact socially with others.
• PD patients also felt the most anxious when they had to speak about themselves.
• In terms of depression, PD patients exhibited, more than the other groups, a loss of energy, feelings of fatigue, and sleep disturbances.

Both Groups (ET + PD)

• Carrying a tray of food across a crowded cafeteria invoked anxiety for both groups.
• Both groups agreed with the statement, “I worry about shaking or trembling when I’m watched by other people.”
• About 60% of both groups were diagnosed with minimal or mild depression, and about 16% were severely depressed.

All Three Groups (ET + PD + Controls)

• Based on the clinical interviews and the written questionnaires, people in all three groups were diagnosed with social phobia, although at different rates:  50% for the ET crowd, 43% of the PD folks, and 20% of the control group.

Authors’ Conclusion

Medical practitioners should treat ET and PD not merely as a neurological condition but as a neuropsychiatric one.

What’s my take on this?  I think it makes sense.  It’s bizarre that PD is labeled a “movement disorder,” because it makes you think just about the external symptoms:  the trembling hand, the limp, the micrographia, the festinating gait, the restless legs at night.  That’s just half the story!  PD messes up not just your brain (inhibiting dopamine production in the substantia nigra), it messes up your mind, too (feelings of anxiety and depression; cognitive decline).

Which leads to a rich question I can ask my neurologist at my next appointment (and/or research on my own):  how does she view the difference between the brain and the mind?  What’s the difference as well as the connections between the two?

If anyone reading this can offer some insight into this mind/brain issue, please comment below.