Antidepressant dispensing trends in New Zealand between 2004 and 2007

The aim of the present study was to explore antidepressant dispensing trends in New Zealand over a 3 year period (2004-2007) with a focus on trends by age, gender, ethnicity, District Health Board and type of antidepressant.

Prevalence of antidepressant agents dispensed in the years ending June 2004-2005, 2005-2006 and 2006-2007 was calculated separately for the population aged 15-24, 24-44, 45-64 and 65-100 years, (> =65) by gender. The f rst occurrence of antidepressant dispensing for each individual in each year was extracted to calculate age-specific antidepressant dispensing rates standardized to the 2006 Census population for the New Zealand European/Other (NZEO) ethnic group.

The 12 month prevalence of antidepressant dispensing among the total population aged 15-100 years increased from 7.36% in 2004-2005 to 8.21% in 2005-2006 and to 9.39% in 2006-2007 Selective serotonin re-uptake inhibitor (SSRI) and tricyclic antidepressants (TCA) accounted for >90% of all antidepressants dispensed each year. SSRIs were more frequently prescribed to young adults (15-24 years) than TCAs, although this relation changed with increasing age. In women aged > =65, TCAs were more commonly dispensed than SSRIs, while among men in the same age group, dispensing patterns were similar for both agents. Age-specific dispensing rates were higher among female than male subjects, and the NZEO combined populations were dispensed significantly more antidepressant agents than Māori or Pacific peoples. Considerable regional variations in antidepressant dispensing were found by ethnicity and gender.

There are considerable variations in antidepressant dispensing in NZ, and the rate of dispensing has increased over the 3 years of the present study. Further work is required to investigate the different rates of antidepressant dispensing found between ethnic groups. Depression is strongly associated with suicide and the trend of increased dispensing of antidepressants found in the present study should continue to have a positive effect on suicide rates in NZ.