An increase in which neurotransmitter is believed to contribute to symptoms of schizophrenia?

Dopamine is the neurotransmitter believed to play a significant role in the development and expression of symptoms associated with schizophrenia. Research has shown that an increase in dopaminergic activity—particularly in certain pathways of the brain, such as the mesolimbic pathway—can contribute to the positive symptoms of schizophrenia, which include hallucinations and delusions.

The dopamine hypothesis of schizophrenia posits that dysregulation and overactivity of dopamine transmission in specific brain regions can lead to these symptoms. This understanding has influenced the treatment approaches for schizophrenia, with many antipsychotic medications aimed at reducing dopamine activity to alleviate psychotic symptoms.

In contrast, endorphins are primarily involved in pain relief and the reward system; serotonin is more associated with mood regulation and has distinct roles in other psychiatric conditions; GABA is a primary inhibitory neurotransmitter that helps regulate anxiety levels. Therefore, while these neurotransmitters are important in various mental health conditions, they do not play the direct role in schizophrenia that dopamine does.