June 2009:

* PSA Tests Are Not Always To Be Relied Upon.

* Some Antidepressants May Cause Diabetes.


PSA Test Results: Strongly Suggestive but Hardly Definitive
PSA (prostate specific antigen) blood tests are used to screen for prostate cancer. While they are often useful, the test gives so many false positive and false negative results that it must be viewed with some reservation. (False positives suggest cancer when there is none; false negatives suggest there is no cancer when cancer is in fact present.)

A number of studies have followed men who had two or more annual PSA tests. Fairly consistently, between 20%and 25% of those who tested positive one year had normal results the following year. In addition, routine biopsies have discovered prostate cancer in a substantial minority of men with normal PSA levels. In some cases these cancers have been aggressive. Hopefully a more reliable test will be developed soon.


Long Term Use of Some Antidepressants May Bring on Diabetes
Depression seems to increase the risk of diabetes, but it has been unclear what the role of antidepressants are in this phenomenon. 2,243 adults who developed diabetes after starting anti-depressant therapy were compared to 8,962 age and sex matched patients without diabetes for a three year period. Factors found to increase the risk of diabetes were:

1) taking certain antidepressants (Paxil (paroxetine), Luvox (fluvoxamine), Effexor (venlafaxine), and Elavil (amitriptyline)) but not others (Prozac (fluoxetine), Celexa (citalpram) or Zoloft (sertraline))
2) taking above the median dose of the medication
3) taking the medication for a longer period of time.

But the strongest predictor of new onset diabetes was being overweight at the time the medication was started. In addition, in my experience, the diabetes inducing antidepressants are more likely than the others to cause weight gain. Patients taking them might want to consult their physicians about been monitored for pre-diabetic or diabetic blood levels or consider a change in anti-depressant medication if that is feasible.