Tryptophan depletion reverses the therapeutic effect of selective serotonin reuptake inhibitors in social anxiety disorder
Section snippets
Subjects and treatment
Prospective subjects were recruited from a tertiary anxiety disorders outpatient clinic that accepts referrals from community mental health teams and general practitioners, as well as self-referrals in response to local media awareness campaigns. An experienced clinician (MA, SH, SA, CB, or JN) made the diagnosis of social anxiety disorder (generalized type), according to DSM-IV criteria (American Psychiatric Association 1994) and by means of a semi-structured interview (Mini International
Characteristics of the sample
Fourteen patients (9 male, 5 female) completed the study, with a mean (SD) age of 39.9 (11.2) years (range: 21–58 years). Mean duration of treatment was 7.8 months (range: 4–12 months). The mean dose of paroxetine (12 patients) at the time of depletion was 32.5 (9.65) mg/day (range: 20–50 mg/day). Two patients were treated with citalopram: one received 30 mg/day and the other 40 mg/day. Five subjects had a history of depression and one of dysthymia, but none was depressed during the treatment
Discussion
In this study, we explored the importance of 5-HT in mediating the clinical effect of SSRIs in the treatment of SAD, using the TD technique. The main finding was that levels of anxiety, as measured with STAI Form Y-1 and VAS, were significantly increased on the TD day compared with the control day, thus indicating that the therapeutic effect of SSRIs in SAD depends on the availability of 5-HT. The increase in state anxiety observed in this study was clinically significant and considerable by
References (48)
- et al.
Brain function in social anxiety disorder
Psychiatr Clin North Am
(2001) - et al.
Effects of fluoxetine administration on mood response to tryptophan depletion in healthy subjects
Biol Psychiatry
(1997) - et al.
Tryptophan-depletion challenge in depressed patients treated with desipramine or fluoxetine: Implications for the role of serotonin in the mechanism of antidepressant action
Biol Psychiatry
(1999) - et al.
Role of 5-HT in stress, anxiety, and depression
Pharmacol Biochem Behav
(1996) - et al.
Dose-response decrease in plasma tryptophan and in brain tryptophan and serotonin after tryptophan-free amino acid mixtures in rats
Life Sci
(1989) - et al.
Relapse of depression after rapid depletion of tryptophan
Lancet
(1997) - et al.
No evidence for in vivo regulation of midbrain serotonin transporter availability by serotonin transporter promoter gene polymorphism
Biol Psychiatry
(2001) - et al.
Epidemiology, patterns of comorbidity, and associated disabilities of social phobia
Psychiatr Clin North Am
(2001) Paroxetine in social anxiety disorder: A randomized placebo-controlled study
Acta Psychiatr Scand
(1999)- et al.
A prospective study of 86 new patients with social anxiety disorder
Acta Psychiatr Scand
(2001)