The article you requested is

Extreme Creatine Phosphokinase Elevation in a 20-Year-Old Man Participating in a Clinical Trial of Major Depressive Disorder

J Clin Psychiatry 2008;69(11):1832-1834 [letter]

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Sir: Creatine phosphokinase (CPK) is an enzyme primarily found in cardiac and skeletal muscle as well as in brain tissue and the gastrointestinal tract. More specifically, CPK is involved in the conversion of adenosine triphosphate and creatine to adenosine diphosphate and creatine phosphate via the transfer of a high-energy phosphate. Minor elevations of CPK occur routinely with strenuous exercise, hypothyroidism, and statinassociated myopathy.​