Which neurotransmitter is associated with increasing anxiety when in excess?

The correct response highlights glutamate as the neurotransmitter that, when present in excess, is associated with increasing anxiety. Glutamate is the primary excitatory neurotransmitter in the brain and plays a crucial role in synaptic plasticity and overall neural activation. When glutamate levels are elevated, it can lead to heightened neural excitability and may contribute to the development or exacerbation of anxiety disorders. This increased excitability can disrupt the balance of neurotransmission, potentially leading to anxiety symptoms.

In contrast, other neurotransmitters have different relationships with anxiety. Dopamine is primarily involved in the reward pathways and motivation but has a complex role in anxiety; it does not have a straightforward correlation with exacerbating anxiety when in excess. Serotonin is often associated with mood regulation, and while low levels can contribute to anxiety, excess serotonin does not have the same direct effect. GABA, on the other hand, is an inhibitory neurotransmitter that helps to calm the nervous system, and its reduction is more closely linked to anxiety rather than an excess. Therefore, glutamate's role in promoting excitatory signals in the brain is pivotal in understanding its connection to anxiety when in excess.