Neurosis, formerly known as neurosis, is a group of mental disorders that manifest mainly as reduced mental activity, worry, stress, anxiety, depression, fear, obsessions, hypochondriacal symptoms, dissociative symptoms, conversion symptoms, or neurasthenia symptoms. As the understanding of neurosis deepened, its concept underwent a series of evolutions, with the general trend of this evolution becoming increasingly deeper and more heterogeneous in connotation, resulting in the almost complete abandonment of the concept of neurosis in ICD-10 and the dismemberment of such disorders into seven different disorders, called neurotic, stress-related, and somatoform disorders.