Current biological approaches to the treatment of depression focus mainly o
n modification of monoaminergic neurotransmission. New agents targeting the
se neurotransmitters are under development. Many novel antidepressant targe
ts are however under investigation. Those include the neurokinins, glutamat
e, purinoceptors, opioids and trophic factors. While many of these potentia
l targets are likely to fail clinical development, exciting novel therapeut
ic options are likely to emerge.