Classification of musical hallucinations and the characters along with neural-molecular mechanisms of musical hallucinations associated with psychiatric disorders

Figure 2 Summary and classification of the publications on musical hallucinations. A: Summary of the publications on musical hallucinations (MHs); The earliest article pertaining to MH was published in 1958. Only 20 articles were identified in connection to MH from 1958 to the end of 1984. As interest in MH grew, more research emerged. From 1990 to end of 1994, there were 31 publications on MH, and this number doubled during the 5-year period from 2015 to the end of 2019; B: Classification of MH-related publications. This pie chart illustrates the classification of the total 238 publications which were selected in this study. These articles can be classified into 5 different classes. The numbers in parentheses represent the total articles of each class.