THE PROPHYLAXIS OF DEPRESSIVE EPISODES IN RECURRENT DEPRESSION FOLLOWING DISCONTINUATION OF DRUG-THERAPY - INTEGRATING PSYCHOLOGICAL AND BIOLOGICAL FACTORS
C. Spanier et al., THE PROPHYLAXIS OF DEPRESSIVE EPISODES IN RECURRENT DEPRESSION FOLLOWING DISCONTINUATION OF DRUG-THERAPY - INTEGRATING PSYCHOLOGICAL AND BIOLOGICAL FACTORS, Psychological medicine, 26(3), 1996, pp. 461-475
Models of long-term treatment in recurrent unipolar illness ideally sh
ould integrate both psychological and biological factors. In earlier r
eports we noted that high treatment specificity (i.e. good-quality mai
ntenance interpersonal psychotherapy) and high delta sleep ratio were
each associated with significantly increased wellness intervals in the
absence of pharmacotherapy among patients with recurrent unipolar dep
ression. To determine how these specific factors when taken together a
re related to length of survival time, we examined the concurrent effe
cts of treatment specificity and delta sleep ratio on wellness interva
ls using survival analysis. We found significant effects of both treat
ment specificity and delta ratio on survival time. Seventy-three per c
ent of the patients in the high treatment specificity/high delta ratio
group survived the 3-year trial, while 44% of the patients in the low
delta ratio but high treatment specificity group survived. None of th
ose rated low on both variables survived. We also found an effect for
individual clinicians on treatment specificity and survival time and n
oted that the prophylactic effect of treatment specificity was maintai
ned even within subsets of therapists grouped by their patients' survi
val times. Secondary analyses revealed an effect of patient attitudes
on treatment specificity and survival time, although, when taken toget
her, treatment specificity was the only variable remaining significant
ly associated with outcome. We conclude that patients remain well the
longest when pre-treatment delta sleep parameters more closely approxi
mate those of non-depressed individuals and when monthly psychotherapy
is of higher quality. The key finding is that high specificity is of
significant prophylactic benefit even for patients with a biological v
ulnerability for recurrence. We also conclude that in addition to ther
apists, patient expectancies contribute to treatment specificity, and
high treatment specificity is, in turn, reflected in longer times to r
ecurrence.