"The physiology of nervous headaches still presents many unsolved problems", as in general do all such "physical alterations...rooted in unconscious instinctual conflicts". However physical discomfort or pain without apparent cause may be the way our body is telling us of an underlying emotional turmoil and anxiety, triggered by some recent event. Thus for example a woman "may be busy in her office, apparently in good health and spirits. A moment later she develops a blinding headache and shows other signs of distress. Without consciously noticing it, she has heard the foghorn of a distant ship, and this has unconsciously reminded her of an unhappy parting".