• Four hypotonic boys (aged 4 years and 11 months, 6 years and 9 months, 7 years and 4 months, and 8 years and 10 months, respectively), all of whom demonstrated a formal thought disorder, had been psychotic for more than six months, and met the DSM-III criteria for chronic undifferentiated schizophrenia, were studied with respect to skeletal muscle morphology. A significant difference between the mean fiber diameters of type I and type II muscle fibers was observed in the three boys with the most severe thought disorder, type II muscle fibers being consistently smaller. No significant difference in the mean fiber diameter between the two fiber types were seen in the fourth boy, who was also the only one who demonstrated any secondary thought process. The boys differed in their activity levels, but there was no correlation between type II muscle fiber atrophy and hypoactivity. It is hypothesized that a depressed cholinergic system is implicated in the pathogenesis of both the muscle fiber atrophy and the formal thought disorder.
Cantor S, Trevenen C, Postuma R, Dueck R, Fjeldsted B. Is Childhood Schizophrenia a Cholinergic Disease?I. Muscle Morphology. Arch Gen Psychiatry. 1980;37(6):658-667. doi:10.1001/archpsyc.1980.01780190056007