Hi, Since the individual is 51 yol, this could qualify for a diagnosis of Dementia w. Early Onset as a primary diagnosis (unless other conditions have been diagnosed) There may be an omission on axis II if the mental retardation (decline of cognition) is caused by the Dementia rather than him always qualifying for such a diagnosis throughout his life. What goes on Axis II would depend on the onset of the retardation. With a score of 64, otherwise it is Mild Mental Retardation if he showed symptoms before age 18. So, what would go on Axis II if anything, would depend on several factors. * If the dementia is suspected to be as a result of Alzheimer's disease, that would be an Axis III diagnosis (Alzheimer's being a ICD-9 medical disorder of the nervous system). A diagnosis of Dementia without behavioral disturbance would be considered a medical ICD-9 code and not a mental health diagnosis. Therefore, the Mental Health Axis I-V would not apply in coding.