2008 ICD-9-CM Volume 1 Diagnosis Codes Home > Mental Disorders 290-319 > Neurotic Disorders, Personality Disorders, And Other Nonpsychotic Mental Disorders 300-316 > Personality Disorders 301.* > 2008 ICD-9-CM Diagnosis 301.21 Introverted personality  On October 1, 2008 the 2009 ICD-9-CM codes came into effect. Therefore, this code may be out of date. The 2009 version of ICD-9-CM 301.21 can be accessed here. 301.21 is a specific code that can be used to specify a diagnosis 301.21 contains 5 index entries View the ICD-9-CM Volume 1 301.* hierarchy ICD9Data's sister site ProcedureCodes.com launches with the 2008/09 CPT® codes - read more on the ICD9Data.com blog. Index entries containing 301.21: Disorder - see also Disease personality 301.9 introverted 301.21 schizoid 301.20 introverted 301.21 Personality schizoid 301.20 introverted 301.21 Schizoid personality 301.20 introverted 301.21 Schizothymia 301.20 introverted 301.21