There's an endocrinologist named Robert Sapolsky who decided at one point to make JMB a poster boy for Psychogenic Dwarfism. The syndrome is when stress causes an individual to stop growing, and Sapolsky decided that David Barrie's death and the "neglect" that JMB experienced afterward triggered this. However, many of the "facts" that he cites about JMB are inaccurate or even completely fictional, such as him being the only child after David died, never undergoing puberty (so the mustache was fake?), having chronic legal troubles for molesting boys, and his age and height at death (60 years, 4ft 10in). He's either gotten JMB confused with some other person, or he's even more careless with the truth than Piers Dudgeon. I wouldn't put much stock in his "diagnosis".