The need to authorise the use of hyoscine to counter hypersalivation caused by antipsychotics has been recently debated by Woochit & Husain (Reference Woochit and Husain2008). They question the logic of the Mental Health Act Commission in suggesting that authorisation needs to be sought on Forms 38 or 39 for detained individuals to receive such medication. They propose a corollary of the Commission's position that all medication used for possible side-effects should similarly be specified, such as senna for constipation and metformin for diabetes.

The Mental Health Act 1983 nowhere defines ‘medication for mental disorder’ in relation to its consent to treatment powers and the courts have never ruled on the question, although the case of B v. Croydon Health Authority [1995] is often cited as a precedent for the contention that a treatment ancillary to the administration of medication for mental disorder can fall within section 58 of the Act (Reference JonesJones, 2006) and therefore requires certification. It is a long accepted practice, for example, that antimuscarinic drugs should be named on the legal forms. Of course this approach could be taken to absurd lengths, meaning that a statutory second opinion might be required to administer a laxative or an indigestion tablet to an incapacitated detained individual.

The Mental Health Act Commission seeks to ensure that forms should provide a clear indication of the limits of any authorisation, both for clinical teams and for the service user, while remaining practical. We therefore seek to distinguish between ancillary treatments that are an essential adjunct to the core treatment, without which the latter could not be reasonably given, and treatments of more widespread physical complaints that may or may not be related to the core treatment.

Hyoscine is a good example of how this distinction should work in practice. Idiopathic sialorrhoea is exceptionally rare. Where it occurs with antipsychotics, in particular but not exclusively with clozapine, it can be said to be almost certainly one of the side-effects of that drug and nothing else. Contrast this with, for example, constipation or indigestion: both are known to be side-effects of psychotropic medication, but are also common intermittent or chronic problems in the general population, often with no exact known cause. From such pragmatic distinctions we have drawn up a list of ancillary treatments requiring certification including, for example, antimuscarinics used in parkinsonism and other motor effects of antipsychotics and hyoscine used for hypersalivation but excluding laxatives, indigestion remedies, or antidiabetics (Mental Health Act Commission, 2002). Our guidance is under review and we would welcome comments and responses to the correspondence address below.