Sir: I was pleased to find the data from my 1979 study of mirror-image studies of depot neuroleptics included in the meta-analysis by O'Ceallaigh and Fahy (Psychiatric Bulletin, December 2001, 25, 481-484). These studies are rarely mentioned today, but they had two principal advantages when they were carried out, and these tend to be overlooked. First, the limited data they collected were as ‘hard’ as it was possible to get. Whether a particular patient is in or out of hospital on a particular day is a fact that even a vestigial record system can generally supply, while there is a legal requirement to record medication that is given.

Second, in a disorder where individual outcome and need for medication vary so widely, each subject is being compared with his/her own previous experience, and not with a theoretical average.

Of course, being in or out of hospital is not always directly equivalent to greater or less morbidity. However, in the circumstances of the NHS or similar services, this equivalent is broadly acceptable. Furthermore, in the real-life world of clinical research, there is simply no alternative to using this measure (Johnson & Freeman, Reference Johnson and Freeman1972, Reference Johnson and Freeman1973).

More fundamental, though, is the historical dimension. Mirror-image studies could only be done when there was a population of patients who had been on oral antipsychotics for a reasonable length of time and who could then be switched to depot treatment. This was possible in the late 1960s and 1970s, but hardly at all after that in Europe. It avoided any ethical problems.

Introducing depot drugs also had the effect of focusing attention on the need for continuity of care in schizophrenia and for setting up registers or information systems to prevent patients being overlooked by services (Reference Freeman, Cheadle and KorerFreeman et al, 1979; Reference Wooff, Freeman and FryersWooff et al, 1983). Historically, this coincided with the birth of community psychiatric nursing, which was able to reach a hard core of people who could not be persuaded to attend clinics regularly. This may be old hat now, but in the early 1970s it was revolutionary.

In Britain, depot treatment was developed by a small number of enthusiasts in provincial non-teaching hospitals. Early research efforts, including my own, were greatly encouraged by modest help from the E.R. Squibb company of the UK and its Medical Director, the late Dr Gerry Daniel. Without them, the effective development of essential maintenance medication — and of research into it — would have been much delayed.