§ Lord Avebury
asked Her Majesty's Government:
What changes in the coding procedure for primary diagnosis of alcoholic psychosis took place in 1979, and what were the numbers of admissions of males and females respectively to mental illness hospitals and units in 1979 and 1980 respectively of persons who would previously have been classified under this heading but are now committed under another heading.
§ Lord Trefgarne
Prior to 1979 the Mental Health Inquiry used a coding procedure based on the Eighth Revision of the International Classification of Diseases 223WA (ICD8). Coding according to the Ninth Revision (ICD9) was introduced in 1979. Several of the changes involved will have affected the numbers of cases in which the diagnosis was coded as alcoholic psychosis.
- (i) Depression and alcohol abuse are no longer combined and coded alcoholic psychosis.
- (ii) Under ICD8, if more than one condition was given, the primary diagnosis was chosen according to a "rule of precedence" by which conditions generally regarded as most severe were given precedence over those which were generally less severe. Under ICD9 the main condition is that identified as being the reason for admission to hospital.
- (iii) ICD8 did not make explicit provision for non-specific depressive disorders whereas ICD9 does and the details of the coding of alcohol abuse have also been improved.
There is some degree of interaction between these changes and it is not possible to say precisely how many people would have been coded as having a primary diagnosis of alcoholic psychosis under the previous system. For example some cases where alcohol abuse and depression are mentioned could be coded under ICD9 to one of the alcohol abuse codes only.