Serotonergic autoreceptor blockade in the reduction of antidepressant latency: Personality variables and response to paroxetine and pindolol

No antidepressant currently in use exerts a significant antidepressant effect for at least two to three weeks alter the patient starts Inking it. Open studies suggest that, for selective serotonergic re-uptake inhibitor (SSRI) antidepressants, this latency may be reduced when the drug is taken with the 5HT¹(A) receptor blocker pindolol. We have undertaken a randomised, placebo controlled, double blind trial of augmentation of the selective SSRI antidepressant paroxetine in combination with pindolol. All our patients (n = 54; mean age 36 [range 19-651) met criteria for major depression and received a standard dose (21 mg o.d.) of' paroxetine plus, randomly, either pindolol (2.5 mg t.d.s.) or placebo for six weeks. We examined personality variables in 48 consecutive subjects according to a short version (TCI-125) of Cloninger et al's self-rated Temperament and Character Inventory (Cloninger et al., 1994) and correlated the results with clinical responses in the trial. The results suggest that personality can influence clinical outcome. After the double blind period patients were offered paroxetine 20 mg or 40 mg for up to 6 months. Twenty-six patients took this up. The results suggest that high scores in the temperament dimension of Reward Dependence and low scores in the temperament dimension of Harm Avoidance had a better outcome at 6 weeks. Patients who had received paroxetine and pindolol during the trial and who reported high Novelty Seeking and low Harm Avoidance scores had a better outcome at 6 weeks and 6 months. We suggest that temperament factors may influence outcome of antidepressant treatment.