GABA (Gamma Aminobutyric acid)• Is the chief inhibitory neurotransmitters in the C.N.S• Counteracts the effects of Glutamate• Via the uptake of negatively charged chloride ions to pass

through the postsynaptic neuron. • Hence post synaptic neuron – less responsive to excitatory

neurotransmitters• Thus GABA has a sedative (tranquilising effect) on the

brain

Dysfunctional GABA system• Normally GABA inhibits physiological responses to an

anxiety producing stimulus• People with a predisposition to phobic disorders have a

GABA deficiency (reduced levels of GABA)• This could be due to over-exposure to stress, poor diet,

excessive caffeine, consumption of psychadelic drugs (e.g. cocaine)

Benzodiazepenes• Benzodiazepene is a sedative

that can be taken to provide a calming effect

• Thus having an agonistic effect by imitating the action of GABA thus inhibiting an overly active physiological response caused by exposure to phobic stimulus.

• By allowing more negatively charged chloride ions to enter the postsynaptic neuron

• Similar affect to alcohol