I am moved to write in response to Paul Wilson and colleagues' letter (3 February) regarding the evidence supporting the use of atypical antipsychotic drugs as the first-line treatment for schizophrenia.

Apart from the gross inaccuracy of their contention - that atypical antipsychotics have not yet been proven to cause less adverse effects or be more acceptable to users than the old antipsychotic drugs - I am concerned that evidencebased medicine and, in particular, randomised clinical trials are being used as a smoke-screen to camouflage a blatant attempt at health rationing in a vulnerable group of patients.

Evidence-based medicine is stratified into five levels of robustness, ranging from expert opinion and sapiential knowledge (level 1), to a randomised controlled trial and accompanying critical review (level 5).

Mr Wilson and colleagues argue that, because there is inadequate level 4 and level 5 evidence, there is no justification for the routine use of these drugs.

This assumption reflects a fundamental philosophical flaw:

just because a treatment has not been subject to adequate randomised controlled trial does not mean that the treatment should not be used (80 per cent of treatments across the whole of medicine have not been subject to randomised controlled trials).

Second, even if one accepts that level 4 and level 5 evidence is lacking, the authors totally fail to take account of level 1 to 3. In a recent survey, 90 per cent of psychiatrists said they would want themselves or their relative to be treated with an atypical antipsychotic if they required neuroleptic treatment.

Ironically only 60 per cent of the same sample were able to prescribe these drugs for their patients (I suspect because of rationing). User-preference surveys clearly report a preference and improved tolerability for atypical drugs, and I have yet to meet any psychiatrist who routinely prescribes for psychotic patients who would deny this.

It should also be noted that atypcials are considerably less likely to cause tardive dyskinesia than conventional antipsychotics.

I and many of my colleagues have sampled both conventional and atypical antipsychotics, so we can put hand on heart and tell our patients we understand their concerns - I defy anyone to do this and use conventional antipsychotics again with a clear conscience. Perhaps they would then appreciate that level 1 to 3 evidence can be compelling without recourse to creating further obstacles to the use of atypicals by demanding ever-more refined randomised controlled trials whose findings will invariably be deemed flawed by those wanting to save money.

Dr Martin Deahl Consultant and senior lecturer in psychological medicine Bart's Hospital London