Therefore, we assumed dose-dispensed drugs to be current medications if filled within 14 days before December 31st 2007, whereas the use of drugs Simetryn delivered in whole packages was assessed using the method described above for OP with incomplete or missing dosage information. For each patient, quality of drug treatment was assessed by five drug-specific quality indicators, developed by the Swedish National Board of Health and Welfare: Ten or more drugs, Longacting benzodiazepines, Drugs with anticholinergic effects, Three or more psychotropics, and Drug combinations that should be avoided. These indicators are all inverted, that is, presence of such treatment, regularly or as needed, indicates poor quality of drug treatment. The quality indicators are described in Table 1. Patient diagnoses were extracted from the VEGA database. As an estimate of burden of disease, the number of different diagnoses in hospital and primary care was summarized for each patient. Our Seratrodast results indicate that MDD is negatively associated with quality of drug treatment. Up to five times as many patients with MDD had poor quality of drug treatment according to drugspecific quality indicators. Interestingly, this finding can neither be explained by their being more ill nor their need to stay in a nursing home, since both number of different diagnoses and residence were included in the model. Indeed, the odds ratios for poor quality of drug treatment for MDD were high as compared with other patient characteristics. Thus, the MDD system seems to be a prominent determinant for poor quality of drug treatment. This finding is interesting, since it indicates that a technology which aims to solve a problem may introduce new problems, as previously discussed. The greatest differences between patients with and without MDD were found for quality indicators concerning number of drugs, Ten or more drugs and Three or more psychotropics. These results could not be explained by a greater burden of disease for patients with MDD. The results confirm previous assumptions that the MDD system increases the number of drugs, and thus adjustments for number of drugs, as made in a previous study, may diminish the estimates of the effects of MDD on drug treatment. Even after adjustment for psychiatric disease, four times as many patients with MDD had poor quality according to the quality indicator Three or more psychotropics. One may speculate that the different prescribing procedures involved in MDD and OP may affect the quality of prescribing. In the MDD system, all prescriptions can easily be renewed at the same time, which could lead to less frequent withdrawals of drugs. In OP, on the other hand, all prescriptions need to be renewed one at a time. To the best of our knowledge, no scientific literature is available on the effects of different prescribing procedures on inclination to make changes in drug treatment, that is, additions, withdrawals, or dosage adjustments, over time.