Based upon the Rome IV criteria, there are distinct functional gastrointestinal disorders (FGID) such as functional dyspepsia (FD) or irritable bowel syndrome (IBS). This categorisation of FGID is intended to help target underlying pathophysiologies or altered functions (e.g. to correct delayed gastric emptying). Contrasting the strict categorisation of FGIDs, a considerable proportion of patients present with an overlap of various FGIDs e.g. FD and IBS. In addition, patients initially presenting with FD may later present with IBS or vice versa. It is now well accepted that patients with severe manifestations of FGID (characterised by significant impact on the quality of life) frequently report extraintestinal comorbidities such as anxiety, depression and have an increased prevalence of somatic problems such as back pain, fatigue or headache. While there is some evidence to support the existence of distinct clusters of GI symptoms from population based epidemiologic studies, data from patients seeking medical care are more likely to report an overlap of symptoms. Indeed, the likelihood of overlap increases with the severity of the symptom manifestation and the impact on quality of life. All this might be aligned with the emerging concept to address FGID as disorders of brain gut interaction. Altered central processing of visceral afferences may result in a spectrum of symptoms related to the whole GI tract rather than symptoms originating from specific organs such as the stomach or colon.