Table 3. Summary of some relevant data in order to emphasize the relation of Helicobacter pylori gastritis and depression.

 H. pylori: Helicobacter pylori, F.D: functional dyspepsia, PMC: PubMed Central®,  GI: gastrointestinal tract, HbA1c: Hemoglobin A1c, SSRIs: Selective Serotonin Reuptake Inhibitors

Study title	Study type	Published	Search method	Conclusion
Uninvestigated dyspepsia and associated factors of patients with gastrointestinal disorders in Dessie Referral Hospital, Northeast Ethiopia [20]	Cross-sectional study	2018	PMC, PubMed	H. pylori strongly associated with F.D
Endoscopic findings in uninvestigated dyspepsia [21]	Cross-sectional study	2014	Google Scholar	High prevalence of F. D with H. pylori
Functional dyspepsia and dyspepsia associated with Helicobacter pylori infection: Do they have different clinical characteristics? (Article in English, Spanish) [22]	Cross-sectional	Sept 2016	Google Scholar	High prevalence of F. D with H. pylori
Correlation between social factors and anxiety-depression in function dyspepsia: do relationships exist?[23]	Cross-sectional	Dec 2016	PMC	Depression strongly associated with F. D
Dyspeptic symptoms in patients with type 1 diabetes: endoscopic findings, Helicobacter pylori infection, and associations with metabolic control, mood disorders and nutritional factors [24].	Cross-sectional	Apr 2015	Google Scholar	Patients with diabetes mellitus type 1 who have dyspepsia are at great risk of having depression at high values of HbA1c and 34% have lesions similar to those having or not dyspepsia
Brain-based Correlations Between Psychological Factors and Functional Dyspepsia [25]	Cross-sectional study	Jan 2015	PMC	Depression strongly associated with F.D
Evidence that independent gut-to-brain and brain-to-gut pathways operate in the irritable bowel syndrome and functional dyspepsia: a 1-year population-based prospective study [26]	Prospective study	22 /July /2016	Google Scholar	Depression strongly associated F.D
Beliefs about GI medications and adherence to pharmacotherapy in functional GI disorder outpatients [27].	Cross-sectional		Google Scholar	People with F.D who are on antidepressant treatment show a great adherence to medication for their comorbidities than those not prescribed antidepressants
The impact of psychiatric and extraintestinal comorbidity on quality of life and bowel symptom burden in functional GI disorders [28].	Cohort study	29 July 2014	Google Scholar	A strong association between F.D and depression
The effect of psychotherapy in improving physical and psychiatric symptoms in patients with functional dyspepsia [29].	Clinical trial	Jan 2015	PMC, PubMed	Psychotherapy is effective in relieving gastric symptoms in patients with F.D
Psychopharmacological approach with the usage of selective serotonin reuptake inhibitors in functional dyspepsia [30].	Clinical trial	Nov 2014	PMC	Using antidepressant in adjunction with quadruple therapy reduces the prevalence of peptic ulcer among patient with anxiety and depression
Psychological effects of Helicobacter pylori-associated atrophic gastritis in patients under 50 years: A cross-sectional study [31].	Cross-sectional	Dec 2017	Google Scholar	H. pylori Seropositive patients show a high risk of having psychological distress and depression
Acute Neuropsychiatric Symptoms Associated with Antibiotic Treatment of Helicobacter pylori Infections: A Review [32].	Review	Jan 2017	Google Scholar	Neuropsychiatric symptoms may occur during the treatment of H. Pylori and rapidly resolute after discontinuation of treatment
Clinical observation on effect of flupentixol and melitracen combined with quadruple therapy on peptic ulcer patients with anxiety and depression (china) [33].	Clinical trial	2015	Google Scholar	Using SSRI in patients with F.D significantly reduce dyspeptic symptoms as well as anxiety and depression
Helicobacter pylori infection impacts on functional dyspepsia in Thailand [34].	Prospective study	2014	Google Scholar	F.D patients commonly have H. pylori and depression, and eradication of H. pylori is the key for treatment.
Ongoing symptoms after eradication of Helicobacter pylori: psychiatric disorders may accompany [35].	Prospective study	Jan 2013	PMC	Psychiatric illness should be excluded in patients who fail symptoms treatment after H. pylori eradication.
Prevalence of Helicobacter pylori Infection and Stress, Anxiety or Depression in Functional Dyspepsia and Outcome after Appropriate Intervention [36].	Prospective study	August 2017	PMC	Dyspepsia score in patients with F.D decreased dramatically after eradication therapy of H. pylori and psychiatric intervention in H. pylori-positive patients
A review of drug therapy for functional dyspepsia [37].	Review	August 2013	Google Scholar	Symptom relief of F.D after H. pylori eradication and the use of antidepressants in a small dose