Chapman and Cox (1977) investigated changes over time in anxiety,

pain, and depression in a group of abdominal surgical patients. Their

results indicated that patients have more anxiety and less depression

preoperatively. "Patients donating kidneys or receiving kidneys from a

live donor had significantly higher pain composite scores and levels of

state anxiety than abdominal surgery patients" (p. 14).

 Wallace (1985) found that preoperative pain expectancy was

positively associated with postoperative reports of pain and high levels

of anxiety. In a second study, she found that subjects given informa-

tion prior to surgery had significantly less postsurgery pain than

controls had. This also supports the concept of cognitive motivational

mediation in the pain process as suggested by Melzack.

 Reading and Cox (1985) in their study of the psychological

predictors of labor pain found that pain ratings on the McGill Pain

Questionnaire were high when compared to other clinical pain groups.

The strongest predictor of the variance was drug use during labor

followed by anxiety measured at 32 weeks' gestation. A significant

association was found between pain ratings and ratings of postpartum

mood, suggesting to the author an association between pain perception

and personality.

 A popular method of assessing postoperative pain is to examine

medication usage. Since 1981, patient-controlled analgesia (PCA) has

been available and in general use in most hospitals. This is a system

in which the patient controls the amount and time of morphine (or other

drug) usage by pressing a button. A preset computer prevents the

patient from taking a dangerous overdosage. Most of the literature