Change in coding conventions for indicating clinically significant psychiatric symptoms occurring as part of a dementia
A coding change adopted by the International Classificaiton of Disease, Ninth Edition, Clinical Modification (ICD-9-CM) Coordination and Maintenance Committee has rendered the subtypes for Dementia of the Alzheimer's Type (i.e., with delusions, with depression, with delirium) obsolete. Specifically, the diagnostic code for Dementia of the Alzheimer's Type is being changed so that the three subtypes that were coded with a fifth digit (i.e., “with delirium,” “with depressed mood,” “with delusions”) are no longer available (see Section 8 for specific details about coding changes).
In order to now indicate comorbid psychiatric symptoms arising from Alzheimer's disease, the new convention is to code the specific mental disorder due to a general medical condition on Axis I alongside the dementia. For example, under Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) coding conventions, an individual with Dementia of the Alzheimer's Type who suffers from the delusion that the aides in the nursing home are trying to poison him would be diagnosed as 290.20 Dementia of the Alzheimer's Type, Late Onset, With Delusions. In Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR), two diagnoses would be assigned: 294.11 Dementia of the Alzheimer's Type With Behavioral Disturbance and 293.81 Psychotic Disorder Due to Alzheimer's Disease, With Delusions. The potential list of secondary conditions that can occur as part of dementia include psychotic disorder due to Alzheimer's disease, mood disorder due to Alzheimer's disease, anxiety disorder due to Alzheimer's disease, personality change due to Alzheimer's disease, and sleep disorder due to Alzheimer's disease.
One complication in adopting this convention, however, is that the DSM-IV criteria set for Personality Change specifically prohibits it from being diagnosed in the presence of dementia (i.e., criterion D states: “The disturbance does not occur exclusively during the course of a delirium and does not meet criteria for dementia”). This exclusion was a carry-over from the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised (DSM-III-R) criteria set for Organic Personality Disorder (which had an identical criterion D). Since the DSM-III-R criteria set for dementia included personality change as one of the defining features, it would have been redundant to allow Organic Personality Disorder to be diagnosed along with dementia. However, since personality change was dropped from the DSM-IV criteria set for dementia, this exclusion should have similarly been dropped from the DSM-IV criteria set for Personality Change due to a General Medical Condition (GMC). Thus, criterion D in Personality Change Due to a GMC has been changed to the following: “D. The disturbance does not occur exclusively during the course of a delirium.”