From: "Saved by Windows Internet Explorer 8" Subject: Questioning the 'neuroprotective' hypothesis: does drug treatment prevent brain damage in early psychosis or schizophrenia? -- Moncrieff 198 (2): 85 -- The British Journal of Psychiatry Date: Fri, 18 Feb 2011 16:49:32 -0000 MIME-Version: 1.0 Content-Type: multipart/related; type="text/html"; boundary="----=_NextPart_000_0000_01CBCF8B.D123F6F0" X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6002.18263 This is a multi-part message in MIME format. ------=_NextPart_000_0000_01CBCF8B.D123F6F0 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Content-Location: http://bjp.rcpsych.org/cgi/content/full/198/2/85
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Editorials |
Department of Mental Health Sciences, University = College=20 London, 67=9673 Riding House Street, London W1W 7EJ, UK. Email: j.moncrieff{at}ucl.ac.uk
J.M. is the co-chair person of the = Critical=20 Psychiatry Network.
Joanna Moncrieff (pictured) is a senior lecturer at=20 University College London and a consultant psychiatrist at = the=20 North East London Foundation Trust.
Almost 7 million prescriptions for antipsychotic drugs were = issued=20 outside hospital in England in 2008, an increase of 48% since = 1998.1 Data=20 from the USA also indicate dramatically increased rates of=20 prescription of antipsychotics to young people over recent=20 years.2 Ideas=20 about the benefits of early drug treatment in psychosis, = along with=20 other factors such as the marketing of bipolar = disorder,3 are=20 likely to have contributed to the increasing prescription of = these=20 drugs.
The importance of starting drug treatment early, and of = continuing=20 treatment in people who would like to stop, is often = justified=20 by the prevalent belief that schizophrenia or psychosis = involves=20 a progressive loss of brain tissue that can be arrested or=20 reduced by treatment with antipsychotic drugs.4=20 Accordingly, the drugs are sometimes referred to as having=20 =91neuroprotecive=92 properties. This belief is founded on a = variety of=20 evidence, all of which is debatable and open to other=20 interpretations.
The great majority of studies of individuals who are drug-naive = or=20 have received only minimal treatment, do not show the global = deficit=20 in brain volume commonly associated with patients who have = received=20 drug treatment, including, most importantly, the only three = studies=20 involving people with long-term conditions who had not been = exposed=20 to drug treatment.7 Results=20 from two studies of people considered to be at high risk of=20 psychosis are also believed to demonstrate progressive brain = tissue=20 loss prior to and in the early stages of psychotic illness. = Many=20 of the Australian cohort, however, were taking antipsychotic=20 medication during some of the follow-up period.8 In the=20 Edinburgh study, high-risk individuals who progressed to = psychosis=20 showed greater temporal lobe reduction than those who did not = progress, but did not differ from controls.9=20 Overall, therefore, imaging studies provide little evidence = of=20 progressive brain tissue loss in non-drug-treated patients = with=20 schizophrenia. Moreover, the effects of drug treatment have = not been=20 excluded as a cause of the tissue loss seen in some studies = of=20 drug-treated patients.7=20
Trials of early intervention have shown some positive results, =
but=20
have not analysed the role of medication over and above other =
aspects=20
of the intervention, and long-term results are disappointing=20
(reviewed in Bosanac et al).15 Two=20
trials of drug treatment for young people at high risk of =
psychosis=20
suggested that the rate of conversion to psychosis was =
reduced,=20
although not by a statistically significant degree in the =
larger=20
of the two trials.16 A=20
larger naturalistic study has so far found that drug =
treatment has=20
not reduced the onset of psychosis.17=20
Effects of antipsychotics, particularly atypicals, on cognitive=20
function is also cited as evidence of their neuroprotective=20
effects, but whether or not any antipsychotics improve =
cognition=20
independently of symptoms remains uncertain. The suggested=20
superior effects of atypical antipsychotics have also been=20
questioned by the findings of the Clinical Antipsychotic =
Trials=20
of Intervention Effectiveness (CATIE) study, in which the =
greatest=20
long-term improvements in cognitive function were seen in the =
perphenazine group.22=20
In contrast to ideas about neuroprotective effects, there is=20
suggestive evidence that antipsychotics reduce brain tissue=20
volume, as described above,7 and=20
they are known to cause the pathological brain syndrome known =
as=20
tardive dyskinesia. Research suggests that as well as =
involuntary=20
movements, tardive dyskinesia is associated with general =
cognitive=20
decline, suggesting that antipsychotics can induce =
generalised brain=20
dysfunction.23=20
Read all eLetters=
TOP
ABSTRACT
INTRODUCTION
Brain imaging research
Neuropathological findings
Duration of untreated psychosis
Evidence=20
on neuroprotection
Conclusions
REFERENCES
At a=20
neuropathological level, ideas about drug treatment being=20
neuroprotective developed because of evidence that some =
psychiatric=20
drugs, notably lithium, increase activity in some pathways=20
associated with neurotrophism and neurogenesis.18 The=20
functional implications of these findings are unclear, =
however. One=20
study, for example, found that although lithium reduced =
levels=20
of kainate-induced excitotoxic motor neuron cell death,=20
surviving cells were not undamaged.19 In=20
any case, evidence of antipsychotics has not consistently=20
demonstrated these sorts of effects.18=20
The view that new atypical antipsychotics have a particular=20
neuroprotective effect may derive from an animal study of =
olanzapine=20
and clozapine that detected upregulation of the =
neuroprotective=20
Bcl-2 (B-cell lymphoma 2) protein.20=20
However, Bcl-2 is also upregulated in neurodegenerative =
disorders=20
such as Alzheimer=92s disease, where it is regarded as =
evidence of a=20
compensatory mechanism. Other studies have not replicated =
this=20
finding, but one study found increased activity of the=20
pro-apoptotic protease capase-3 in animals treated with old =
and new=20
antipsychotics.21=20
TOP
ABSTRACT
INTRODUCTION
Brain imaging research
Neuropathological findings
Duration of untreated psychosis
Evidence on neuroprotection
Conclusions
REFERENCES
Antipsyc=
hotics=20
are undoubtedly useful in suppressing the symptoms of =
psychotic=20
conditions, but the evidence presented here suggests there is =
little=20
basis to the belief that they reverse an underlying =
neurodegenerative=20
process in people with schizophrenia or psychosis. =
Neuropathological=20
studies do not support the idea that antipsychotic drugs, =
including=20
the new or atypical antipsychotics, have neuroprotective =
effects.=20
Some research suggests they may even contribute to the =
decline in=20
brain volume seen in people with these diagnoses, and they =
are known=20
to induce neurological damage in the form of tardive =
dyskinesia in=20
some long-term users. The idea that antipsychotic drugs are=20
neuroprotective should not therefore be used as a =
justification for=20
prescribing or continuing to prescribe them, if other =
considerations=20
do not also support their use. Psychiatrists should be =
particularly=20
cautious about the use of antipsychotics in the early or =
prodromal=20
stages of psychosis, where, as others have pointed out, there =
is=20
the potential to do much harm.15=20
TOP
ABSTRACT
INTRODUCTION
Brain imaging research
Neuropathological findings
Duration of untreated psychosis
Evidence on neuroprotection
Conclusions
REFERENCES
1=20
Received for publication =
August=20
11, 2010. Accepted for publication September 15, 2010.
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