Hi. Thanks for your query. Noted the history about your friend and understood the concerns. Since heart surgery was performed 10 years ago, this may not be related to the one month old symptoms. Yes, this is possible that tensions of any sort can cause loose motions and this is called IBS or irritable bowel syndrome.This is a diagnosis by exclusion. Hence I would advise your friend the following in such a situation. Get the stool tests done for three consecutive days. Tests of blood for CBC, thyroid, liver functions and other tests as may be decided by the Gastroenterologist on clinical evaluation and examination. CT scan of abdomen and COlonoscopy. All these will lead to a definitive diagnosis and thus should get a line of management if a specific cause is found. If all the tests are normal this should be said to have IBS wherein reduction or management of anxiety and stress is the basic key. Also ask him to identify the foods and beverages that instigate or enhance the problems and thus stop such factors altogether.