When something is causing worry, there are various synonyms one may use depending on the context. One common synonym is "disturbing", which implies that a person or situation is causing a disturbance in one's peace of mind. Another similar word is "disconcerting", which suggests that something is causing a feeling of unease or discomfort. "Troubling" is another synonym that conveys a sense of unease and anxiety. "Alarming", on the other hand, suggests a sense of immediate concern for a person's safety or well-being. Lastly, "unsettling" emphasizes that something is causing a sense of disruption or upheaval to one's emotional state.