Pain and mood over time after surgical discectomy. In each panel, the four curves represent subgroups of 153 surgical patients divided according to the percentage reduction in "bodily pain" from the baseline to the three month rating. Top left: Bodily pain plotted against time over three years postoperatively. Top right: SF-36 Mental Health scores plotted against time. Higher values on the y axis correspond to less depressed or anxious feelings. Note that mood sharply improves at the first postoperative point in the three subgroups of patients with 25–100% reduction in pain, but mood does not worsen in the group with minimal pain relief. Bottom: The items specifically related to depression (left) and anxiety (right) show similar relations to pain reduction.