The biochemical effects of neuroleptic drugs are reviewed step by step. The necessity to go beyond such a didactic way is highlighted considering two points; on the one hand neuroleptic drugs do affect more than one neurotransmitter system and on the other hand monoaminergic and peptidergic system exert reciprocal influences. From this point of view the consequences of the biochemical effects of neuroleptic drugs remain a wide open road for clinical pharmacology.