In gastritis, if the response with 30 mg Lansoprazole is partial, increasing the dose will be helpful.
If there is no response at all with 30 mg lansoprazole, then increasing the dose might not be helpful.
And also there are a few high acidity conditions where high doses of PPI has to be taken for control of symptoms.
Endoscopy is done to find if the cause of pain in the upper abdomen is due to gastritis or not.
If endoscopy is normal, H pylori is negative, scan shows normal other organs, then functional dyspepsia is diagnosed and in addition to PPI, you may have to take Amitriptyline.
Alternatively if you have been on Lansoprazole for a longer time, you can switch over to another PPI like Nexium.