Space cafard was a type of disease, a much feared and highly contagious psychological side-effect of working in space for long amounts of time. Brought on by boredom, Space cafard afflicted the crew of the starship Westmoreland prior to 2266. In 2267, the USS Enterprise placed many crew members into stasis to prevent the spread of space cafard. (TOS novel: Mission to Horatius)
- Leonard McCoy's concern over the development of this highly contagious psychological disease is revisited throughout the novel. Given that this was the very first (original) Star Trek novel and that it was written primarily for children, much of the plot is forgivably unrealistic. This includes "space cafard," which is, basically, a "disease" caused by boredom. Cafard is designed as "melancholy, boredom, listlessness, etc." at http://www.yourdictionary.com/cafard .