Dear Charles, I think that stress has to be a factor in PD along with other causes. I habe been studying neuropsychology of late, and iit seems that the Dopamine pathway goes through two critical periods of development which the synapses are developing at a rapid rate. One of these is right after birth for a few months, and the other begins around the end of the send year and extends into the next year or two or three. At these times, the sympathetic nervous system is getting set involving the viscera, movement, and the endocrin system to the extent that they are affected by dopamine. Also at this time the regulation ( first yr. ) and inhibition (second yr. ) of affects are being encoded in the same neurons, based on the infant-care-giver environment. Therefore, the individual's ability to regulate stimulation and self calming will be intricately intertwined with the development of the dopamine pathway--lateral tegmental, I believe. Also, the adrenergic pathway, responsible for regulating the parasympathetic nervous system, reacts to stress by releasing epiinephren and norepinephren, which inhibit the flow of dopamine, and throw the body into the stress state--rapid heart rate, etc. Therefore, when the PD pt. gets anxious, for example, it can precipiitate a going off. My own PD symptoms began to appear right after the birth of my first child, and became exacerbated after the birth of my second. A year later I had a surgery, and the tremor appeared so that after 7 years I got a diagnosis! Claudia