Inhibitory neurotransmitters are the chemical messengers released by neurons which inhibit activation in the receiving neuron. They have a calming effect on the brain. These include serotonin, GABA and dopamine (which can also act as an excitatory neurotransmitter).Queensland Brain Institute. (n.d.). What are neurotransmitters? [online] Available at: https://qbi.uq.edu.au/brain/brain-physiology/what-are-neurotransmitters [Accessed 19 Nov. 2018]. Biocoherence Nederland. (n.d.). How do Neurotransmitters deficiencies influence my Behaviour, Mood, Concentration and Motivation? [online] Available at: https://www.biocoherence.eu/en/questionnaires/neurotransmitters/ [Accessed 19 Nov. 2018].