Studies in adults have indicated a significant relationship between high serum
creatine kinase levels on admission and acute
psychosis. However, data on children are sparse. The files of 183 hospitalized children and adolescents (93 boys, 90 girls) with severe
psychiatric disorders were reviewed for serum
creatine kinase activity on admission,
psychomotor agitation, Clinical Global Impression Score, need for
intramuscular injection, number of
neuroleptic medications and presence of
neuroleptic malignant syndrome. Serum
creatine kinase levels > 201 IU/ml were considered abnormal. Boys had significantly higher
creatine kinase activity than girls. Division of the cohort by diagnosis yielded significantly higher levels in those with
schizophrenia,
affective disorders and
mental retardation. Higher levels were also associated with higher Clinical Global Impression score on admission, use of
injections and physical restraint, and nonresponse to
neuroleptic medication. There were no cases of
neuroleptic malignant syndrome. This first large-scale investigation of serum
creatine kinase activity in young psychiatric inpatients shows a significant association between high
creatine kinase activity and acute
psychosis, similar to that in adults. Furthermore, high
creatine kinase levels on admission are predictive of the severity of the
psychosis, but are not associated with
neuroleptic malignant syndrome. Because psychotic adolescents with high admission
creatine kinase levels tend to be nonresponders, clinicians should consider the early use of atypical
antipsychotics in this subgroup.