A depressed person may report multiple physical symptoms such as fatigue, headaches, or digestive problems; physical complaints are the most common presenting problem in developing countries, according to the World Health Organization's criteria for depression.[29] Appetite often decreases, with resulting weight loss, although increased appetite and weight gain occasionally occur.[2] Family and friends may notice that the person's behavior is either agitated or lethargic.[3] Older depressed people may have cognitive symptoms of recent onset, such as forgetfulness,[4] and a more noticeable slowing of movements.[30] Depression often coexists with physical disorders common among the elderly, such as stroke, other cardiovascular diseases, Parkinson's disease, and chronic obstructive pulmonary disease.[31]