Age-dependent antidepressant pharmacogenomics:: polymorphisms of the serotonin transporter and G protein β3 subunit as predictors of response to fluoxetine and nortriptyline

In 169 depressed patients randomized to treatment with either fluoxetine or nortriptyline, we examined whether polymorphisms of the serotonin transporter and the G protein beta3 subunit influenced response to these anti depressants. For depressed patients under the age of 25 yr the T allele of the G protein beta3 subunit was associated with a markedly poorer response to nortriptyline, while serotonin transporter polymorphisms did not predict antidepressant response. However, in patients 25 yr or older, the G protein beta3 polymorphisms did not predict antidepressant response, while the ss genotype of the serotonin transporter was associated with a poorer response to both fluoxetine and nortriptyline. These differential pharmacogenetic predictors of antidepressant response by age, may provide clues to understanding the discontinuities in pharmacological responsiveness of child/adolescent and adult depressive disorders.