Atypical antipsychotics decrease levels of which neurotransmitter?

Atypical antipsychotics primarily target the neurotransmitter systems associated with both dopamine and serotonin, but the correct focus regarding the significant decrease in neurotransmitter levels is serotonin.

These medications are designed to address symptoms of schizophrenia and other mood disorders by modulating neurotransmitter activity, particularly in pathways that involve serotonin (5-HT) receptors, along with their interaction with dopamine receptors. The unique action of atypical antipsychotics typically results in a blockade of the 5-HT2A receptors, which can lead to a decrease in serotonin activity in certain neural circuits, contributing to their therapeutic effects and side effect profiles.

While dopamine is often decreased by typical antipsychotics, atypical agents result in a more balanced approach by also specifically affecting serotonin pathways, which is why the choice highlighting serotonin as decreased is correct. In this context, norepinephrine and GABA are not primarily targeted by atypical antipsychotics in terms of their clinical efficacy, making them less relevant to this inquiry.