Dopamine and Serotonin Interactions in Schizophrenia: A Focused Review of Mechanisms and Therapeutic Implications

Schizophrenia is a chronic and complex mental illness that substantially impacts a person’s thoughts, emotions, and daily life. It is characterized by a combination of positive symptoms such as hallucinations and delusions, and negative symptoms such as emotional withdrawal, lack of motivation, and cognitive difficulties. Historically, the dopamine system has been the forefront of research on schizophrenia, but serotonin’s role has recently come into sharper focus. While serotonin is necessary for regulating emotions and mental processes, dopamine imbalances are known to result in psychotic symptoms and cognitive impairments. Interactions between these neurotransmitters affect brain functions. Many patients have seen better results due to advancements in treatment, especially second-generation antipsychotics that target both the dopamine and serotonin systems. However, challenges still exist, especially in effectively managing negative and cognitive symptoms. This review highlights key findings that support a more integrative model involving serotonin-dopamine interactions, emphasizing the role of receptors such as dopamine receptor D1, dopamine receptor D2, 5-hydroxytryptamine 1A (5-HT1A), and 5-hydroxytryptamine 2A (5-HT2A). It also explores the therapeutic potential of newer agents like brexpiprazole, cariprazine, and pimavanserin, which offer more targeted symptoms control with fewer adverse effects. Additionally, emerging research on the gut-brain axis and glutamatergic modulation presents promising directions for future treatment strategies. In this review, we looked at the research on the roles of dopamine and serotonin in schizophrenia and discussed the therapeutic approaches that could lead to more comprehensive and effective treatment plans.