Assessing the use and effectiveness of antipsychotic medication

Taylor, Mark (2013) Assessing the use and effectiveness of antipsychotic medication. MD thesis, University of Glasgow.

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Abstract

Background.
Antipsychotic medications are widely prescribed for schizophrenia and other related psychiatric conditions, but can have serious financial costs and adverse effects. The evidence base concerning the efficacy; effectiveness; and adverse effects of antipsychotic medications is extensive but variable in quality and applicability, and controversy continues to exist as to whether the newer medications are superior to the older antipsychotics. Locally derived data on the use and effectiveness of these medications can inform their future use, and complement the national and international studies.

Aims & objectives
To review the pertinent literature regarding antipsychotic medication, and to examine the use and clinical effectiveness of antipsychotic medication in a local context. Also to develop a valid but pragmatic scale to monitor the adverse side effects of antipsychotic medications.

Methods
A pre-existing case register was analysed to describe the contemporary patterns of antipsychotic usage. For the original data containing studies, one prospective and two retrospective attributions of clinical global impression (CGI) scores, as well as continuation and hospitalization rates were examined. The side effect scale (GASS) was devised after literature review and patient consultation, and tested on consenting patients in comparison to a well established existing scale (LUNSERS) and on healthy individuals.

Results
Data from the Glasgow city case register shows antipsychotics are widely and appropriately prescribed there but polypharmacy is common. In the prospective 6 month study, olanzapine and risperidone produced significant improvements in CGI but lack of power precluded similar conclusions with amisulpride, clozapine, and quetiapine. In the retrospective studies, clozapine was clinically superior to other oral antipsychotics but there was no significant clinical difference between the main 3 depot or long acting antipsychotics studied. The new side-effect scale – the GASS - was found to be easy to use and as discriminating as the LUNSERS.

Discussion
There can be difficulties generalizing data from short term RCTs to routine clinical practice. However this thesis demonstrates that simple but robust measures such as the CGI or GASS can be used to structure and inform everyday clinical practice. Consistent with the evolving debate on the relative merits of individual medications, this thesis showed there was little difference in clinical effectiveness between various oral antipsychotics, with the exception of clozapine. The lack of a significant difference between the old and newer long acting injectable antipsychotics is a new finding, and this area merits further study.

Conclusions
Structured routine monitoring of outcomes is possible in the NHS with regard to antipsychotic medication. Oral and LAI (or depot) antipsychotic medications continue to differentiated more by their adverse side effect profile rather than their relative effectiveness, with the exception of clozapine A new short, inclusive, and valid side-effect monitoring scale – the GASS - is introduced.

Item Type: Thesis (MD)
Qualification Level: Doctoral
Keywords: Antipsychotics, effectiveness, GASS
Subjects: R Medicine > RM Therapeutics. Pharmacology
Colleges/Schools: College of Medical Veterinary and Life Sciences > Institute of Health and Wellbeing > MRC/CSO Unit
Supervisor's Name: Cavanagh, Dr. Jonathan
Date of Award: 2013
Depositing User: Dr Andrew Mark Taylor
Unique ID: glathesis:2013-4227
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 23 May 2013 13:46
Last Modified: 23 May 2013 13:46
URI: http://theses.gla.ac.uk/id/eprint/4227

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