Rock fever and island fever are colloquial terms for a form of mental distress said to mainly afflict mainlanders who move to isolated islands, especially any of the Hawaiian islands or Guam. It is neither a medical term nor a classification, and it has not been the focus of any serious research. It has been described as "an ailment" of feeling "stifled by [the island's] size and isolation", making its sufferers "anxious, irritated, desperate, and claustrophobic." It is often ascribed to homesickness. Rock fever has also been described as a feeling of isolation that could arise in any isolated place and affect anyone, including native inhabitants.
Although I was often warned about the isolation of living in Hawaii. That is the infamous 'rock-fever,' I have personally never felt it. The awesome beauty of my home state never ceases to amaze me, and I always miss it enormously when I travel.
For years, Guam would be the butt of jokes in the United States as an uninviting place, where boredom led to "rock fever," a cranky longing to get off the island.