Due to the wide range of symptoms Parkinson's patients manifest, some of them naturally overlap, making it difficult for any doctor to diagnose. Fatigue being a common symptom not just of Parkinson's but many disorders, can be viewed as the patient being apathetic or depressed. There is a huge difference between fatigue, depression and apathy, none of which should be bundled together or confused. Depression can be treated with various antidepressants, but if wrongly diagnosed and the patient is suffering fatigue and apathy, then the antidepressant is not going to work. I believe it is therefore crucial, when seeing your neurologist, to paint a clear picture (and I don't mean arrive at his office with easel, paints and brushes) but to express in the best way you can exactly what you are experiencing, being open and speaking honestly about your concerns. This is where you have to be your own advocate, for although it is advisable to attend all doctors appointments with your caregiver, spouse or someone close, they may have a very different view on this particular element of the disease.
Masking also can give the impression that a person looks bad tempered, cross or down - when in fact their mood might be perfectly fine, simply the "masking effect" projects a different picture. When I feel my face freeze, I know I have a blank expression as if I don't know what's going on around me, yet my mind is sharp, I have complete clarity, and am able to express myself whether speaking or writing. In other words, don't jump to conclusions and judge when you are in the company of someone with Parkinson's.