Paul Bebbington (letters, 18 November) claims the Royal College of Psychiatrists' draft guidelines on the atypical antipsychotics are a 'major scientific analysis of (their) overall effectiveness'. To judge by his comments on older, typical drugs, there was little analysis of the these agents' effectiveness.

If movement side-effects are to be avoided, as Professor Bebbington rightly suggests, then older typical drugs cannot be recommended, even at low doses. In normal clinical use, typical antipsychotics engender an unacceptable adverse effect burden. At any time, acute movement side-effects are experienced by 30 per cent of patients, and longer-term abnormal muscular movements by up to 20 per cent. Other adverse effects also occur.

Using lower doses of typical drugs makes virtually no difference: acute movement side-effects commonly occur at doses too low to produce any therapeutic effects, while tardive dyskinesia is induced even by minuscule doses.

To suggest that older typical drugs can be used without unpleasant adverse effects is disingenuous. Given the evidence, to suggest they should be used as first-line agents and changed only after adverse effects occur is knowingly to do harm.

David Taylor Chief pharmacist Maudsley Hospital Honorary senior lecturer Institute of Psychiatry