A 21-year-old male college student was brought to Student Health Services by his girlfriend who was concerned about changes in her boyfriend’s behaviors. The girlfriend says that recently he began hearing voices and believes everyone is out to get him. The student says he is unable to finish school because the voices told him he was not smart enough. The girlfriend relates episodes of unexpected rage and crying. Past medical history noncontributory but family history positive for a first cousin who “had mental problems”. Denies current drug abuse but states he smoked marijuana every day during his junior and senior years of high school. He admits to drinking heavily on weekends at various fraternity houses. Physical exam reveals thin, anxious disheveled male who, during conversations, stops talking, cocks his head and appears to be listening to something. There is poor eye contact and conversation is rambling.

Based on the observed behaviors and information from girlfriend, the APRN believes the student has schizophrenia.
Question: The APRN reviews recent literature and reads that neurotransmitters are involved in the development of schizophrenia. What roles do neurotransmitters play in the development of schizophrenia?