Effects of antipsychotic medications on dementia – Analysis of CATIE-AD study

Dementia is known to cause memory impairment, personality change, problems in judgments, and intellectual impairment. These changes taken together are called impairments in cognitive capacity.

Doctors usually prescribe antipsychotic medications for dementia, especially to calm down acutely disturbed patients. In addition, some patients are given regular dose of antipsychotics as a maintenance therapy to improve sleep and agitation. Most common antipsychotics prescribed are Risperidone (Risperdal®), Quetiapine (Seroquel ®), and Olanzapine (Zyprexa®).

However, there is a recent debate among doctors regarding the long term outcome of this practice. One of the reasons is the blood lipid abnormalities seen in patients who are prescribed atypical antipsychotics such as Risperidone (Risperdal®), Quetiapine (Seroquel ®), and Olanzapine (Zyprexa®). This could lead to heart problems such as heart attacks. In addition, these problems could increase the memory impairment seen in Alzheimer's disease due to blockage of vessels in the brain.

Now doctors have concluded several studies on this regard. One of such is the “Clinical Antipsychotic Trials of Intervention Effectiveness–Alzheimer's Disease study (CATIE-AD)” study. As the name suggest it looked into the relationship between prescription of antipsychotic medications and Alzheimer’s dementia. This study mainly looked at memory impairment and other cognitive impairments seen in dementia patients who are prescribed antipsychotics.

How the CATIE-AD study is conducted?


This study carried out in more than 400 patients. Most of them are community dwelling moderate to severe dementia patients. These patients were randomly allocated to different treatment groups and they were prescribed Risperidone, Quetiapine and Olanzapine. In addition, patients were given different medications in different times similar to crossover design. This study was carried out around three years.

Results of the study


This study reported a statistically significant cognitive impairment associated with antipsychotic medications. That means people who were prescribed antipsychotics showed greater memory impairment than the people who were not prescribed them.

Background


Many other studies that were performed around the time showed conflicting results.

Conclusions
This study is not a very large study and the cross over design can have many problems that would change the outcome. However, it will certainly put more weight on the argument that antipsychotics cause cognitive impairment. But other options available for agitation and psychosis seen in dementia patients such as benzodiazepines may also cause cognitive impairment. Therefore, in practice it is difficult to stop prescribing antipsychotics for patients with dementia.

Sources
Consequences of Antipsychotic Medications for the Dementia Patient - Am J Psychiatry 168:767-769, August 2011