Cannabis sometimes causes dysphoria rather than euphoria; however, evidence relating to the interaction between the cannabinoid and 5-hydroxtryptamine (5-HT) systems is limited, especially in areas of the brain such as the amygdale. Here we report that cannabinoid CB(1) receptors and 5-HT transporter proteins are co-distributed in the amygdale, suggesting the possibility that activation of cannabinoid CB(1) receptors might cause a reduction in 5-HT release, similar to its effect on other neurotransmitters, thereby resulting in dysphoria.