The Feb 2008 issue of *British Journal of Psychiatry* (vol. 192, #2) includes a study: “Antidepressant medications v. cognitive therapy in people with depression with or without personality disorder.”

The study is by Jay C. Fournier, Robert J. DeRubeis, Richard C. Shelton,
Robert Gallop, Jay D. Amsterdam, & Steven D. Hollon

Here’s the abstract:


There is conflicting evidence about comorbid personality pathology in
depression treatments.


To test the effects of antidepressant drugs and cognitive therapy in
people with depression distinguished by the presence or absence of
personality disorder.


Random assignment of 180 out-patients with depression to 16 weeks of
antidepressant medication or cognitive therapy. Random assignment of
medication responders to continued medication or placebo, and comparison
with cognitive therapy responders over a 12-month period.


Personality disorder status led to differential response at 16 weeks;
66% v. 44% (antidepressants v. cognitive therapy respectively) for
people with personality disorder, and 49% v. 70% (antidepressants v.
cognitive therapy respectively) for people without personality disorder.
For people with personality disorder, sustained response rates over the
12-month follow-up were nearly identical (38%) in the prior cognitive
therapy and continuation-medication treatment arms. People with
personality disorder withdrawn from medication evidenced the lowest
sustained response rate (6%). Despite the poor response of people with
personality disorder to cognitive therapy, nearly all those who did
respond sustained their response.


Comorbid personality disorder was associated with differential initial
response rates and sustained response rates for two well-validated
treatments for depression.