An Introduction of Synesthesia’s Psychological Symptoms and its Correlation with Major Neuropsychiatric Disorders

Abstract

Synesthesia is defined as a subjective phenomenon that a stimulus could spontaneously evoke a concurrent but unrelated sensation. Previous studies have predominantly focused on understanding the phenomenon in isolation, examining various aspects such as different types of synesthesia, their causes, etiology, and heredity. By conducting studies on synesthesia alongside existing investigations, researchers can gain valuable knowledge about how the non-synesthetic mind operates, shedding light on aspects such as awareness and neurological disorders. This literature review aims to examine the psychological symptoms and psychiatric characteristics of synesthesia, focusing on three common types that pertain to color, numerical cognition, and synesthetic-like experiences. Additionally, the review will explore the intersection between synesthesia and major types of neuropsychiatric disorders, highlighting that the occurrence of mental illnesses or neurological impairments among synesthetes aligns with the prevalence in the general population. Thus, synesthesia could serve as an additional tool for studying the human brain and cognition. There are still a lot of limitations in the present research that we need more evidence and data to further support it. The study of synesthesia might provide a promising platform for testing various concepts and theories across diverse realms of cognitive science.