Motion Sickness Symptoms

Question:
I start feeling nauseous after playing a few levels of a FPS. ie, Doom, MOH(both of which I got rid of due to this). Strangely, flight sims like G-Police 2 and Ace Combat 2 which I use with the 1st-person view don't make me feel ill. Sometimes after I've played 3rd-person games for quite a while I start to feel slightly ill as well! Has any one else experienced this? Is it it due to lighting, or movement effects(motion sickness?) or really getting involved in the gameplay and getting over-excited? Did you find a FPS that didn't make you feel ill?

Answer:
I did a little digging in Medline, and it seems that adaptation, ie getting used to the mismatched signals, is apparently the preferred treatment, though a scopolamine patch has been used to good effect in at least one case. I've cut and pasted some of the abstracts below, in case anyone might be interested in some of the details:
"The time course of postflight simulator sickness symptoms." Aviation Space & Environmental Medicine. 60(11):1043-8, 1989 Nov.
Reports of posteffects following training sessions in Navy and Army flight simulators were obtained from pilots to determine the time course of recovery from simulator sickness. Results imply that posteffects may be a more serious problem than previously considered; 45% of all those queried
(N greater than 700) reported having experienced symptoms of simulator sickness; 25% of the symptoms lasted more than 1 h after leaving the simulator; and 8% lasted more than 6 h.
Postexposure symptoms were classified into three categories: visuomotor
(based on disturbances in oculomotor control; e.g., eyestrain), disorientation (based on disturbance in postural control; e.g., dizziness), and nausea (vagal/autonomic symptoms). A safety risk may be posed particularly by the moderately high frequency of symptoms involving postural disequilibrium. Guidelines for coping with risks are discussed.

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