Growth in Prescribing of new Anti-depressants in New Zealand 1993-1997, Including Comparisons with the Nordic Countries

Objective: This paper analyses the growth in prescribing of new anti-depressants in New Zealand, using published data from the Nordic countries as a comparison. We look whether new anti-depressants are, at an aggregate level, substituting for or adding to the use of older agents. We also examine regional variation in the adoption of the new agents. Method: Data on anti-depressants dispensed by New Zealand pharmacies between 1993 and 1997, which were subsidised by the government, were analysed. Dispensings were mapped to regions using the location of the pharmacy. Key findings: New Zealand consumption of anti-depressants, and tricyclic drugs in particular, was very high. The use of selective serotonin reuptake inhibitors (SSRIs) grew steadily throughout the period studied, but not as strongly as in the Nordic countries. In New Zealand there was considerable regional variation in overall anti-depressant use, and in the ratio of newer to older drugs. This ratio changed considerably over the period studied, with regions with low use of newer drugs tending to catch up with those with higher levels. Conclusion: New Zealand's switch to SSRIs appears to be more cautious than that of the Nordic countries. The study of regional prescribing patterns may help to explain some of the patterns identified at national level.