I say they definitely can.
For me they would come in cycles where I would have certain intense symptoms, and then at another time I will have other distinct symptoms that are more mellow.
For example my intense symptoms can be nausea, sweating, twitching, shaking, throbbing arms, and rapid heart beat. My mellow symptoms are gag sensation, tiredness, and lack of motivation. Those symptoms can flow in a circular motion where they go away and come back.
Post Edited (BlakeT) : 1/9/2018 7:37:15 AM (GMT-7)