Final answer:
Overproduction of neurotransmitters can cause symptoms of anxiety, depression, and anger, but not excitement.
Step-by-step explanation:
Overproduction of neurotransmitters can cause all of the following conditions to occur, except Excitement. When there is an excess of neurotransmitters in the brain, it can lead to imbalances in the neural pathways and disrupt normal brain function. This can manifest as symptoms of anxiety, depression, and anger. However, excitement is typically associated with increased neurotransmitter activity, rather than overproduction.