Caffeine has a number of adverse effects on the gastrointestinal tract. It relaxes the lower oesophageal sphincter and can predispose to gastro-oesophageal reflux disease. It also causes gastric hypersecretion, which is associated with susceptibility to ulceration.
http://apt.rcpsych.org/content/11/6/432
If you love the taste of coffee or tea but want to reduce your levels of caffeine and anxiety, there are plenty of brands, both instant and fresh, from which the caffeine has been removed but that taste very like the real thing.
http://www.stressbusting.co.uk/caffeine-and-anxiety/
Caffeine and anxiety are linked, however, because the boost we get from caffeine is caused by an increase in our heart and breathing rate. These are the same reactions as the “fight or flight” response that kicks in when we sense danger, or a challenge we can’t cope with.
http://www.stressbusting.co.uk/caffeine-and-anxiety/
But that's not at all: Abuse of alcohol or drugs can also lead to an anxiety disorder or an anxiety attack. People with social anxiety who abuse alcohol have been shown to be more likely to have severe symptoms of anxiety — as well as other emotional problems and health conditions.
http://www.everydayhealth.com/anxiety-pictures/7-surprising-causes-of-anxiety.aspx
Elsewhere in the body, caffeine causes relaxation of smooth muscle (especially bronchial smooth muscle) and stimulation of cardiac muscle; these effects resemble those of β-adrenoceptor stimulation. The stimulatory effect on the heart can result in tachycardia at high doses.
http://apt.rcpsych.org/content/11/6/432
Biochemistry and pharmacology of caffeine. Caffeine is a methylxanthine (1,3,7-trimethylxanthine). The effects of this group of chemicals include stimulation of the central nervous system (CNS), diuresis, stimulation of cardiac muscle and relaxation of smooth muscle.
http://apt.rcpsych.org/content/11/6/432
In fact, caffeine's jittery effects on your body are similar to those of a frightening event. That's because caffeine stimulates your fight or flight response, and studies show that this can make anxiety worse and can even trigger an anxiety attack.
http://www.everydayhealth.com/anxiety-pictures/7-surprising-causes-of-anxiety.aspx
Drinks that contain caffeine. The results of an official UK survey of caffeine levels in drinks ranged from 1mg for the weakest tea to 254mg for the strongest cup of ground coffee. Drinks like cola, some sodas and those with chocolate or guarana all contain caffeine, as do a lot of sports and energy drinks. If you are concerned about caffeine and anxiety it’s a good idea to check the labels. Amount of caffeine in drinks. Mug of filter coffee 140mg.
http://www.stressbusting.co.uk/caffeine-and-anxiety/
But if your thyroid produces too much, it can cause anxiety symptoms, such as nervousness, irritability, heart palpitations, and sleeplessness. If you have anxiety symptoms along with swelling in your neck, weight loss, weakness, fatigue, or heat intolerance, ask your doctor to check your thyroid gland.
http://www.everydayhealth.com/anxiety-pictures/7-surprising-causes-of-anxiety.aspx
If you've ever had a panic attack, you're familiar with the way your hands get clammy, you can't catch your breath — and your heart feels like it's going to pound right out of your chest. But problems with your heart can also be the cause of anxiety. In fact, after a heart attack or heart surgery, about one-third of people experience anxiety symptoms such as heart palpitations and shortness of breath. These symptoms often last up to one year or more, and they're more common in women.
http://www.everydayhealth.com/anxiety-pictures/7-surprising-causes-of-anxiety.aspx
what causes restlessness besides caffeine
Caffeine's jittery causes restlessness besides caffeine.   Caffeine's jitters causes restlessness besides caffeine.