This study compared fluency changes in adult
developmental stuttering speakers treated with two
tricyclic antidepressants,
clomipramine and
desipramine.
Clomipramine is primarily a serotonergic reuptake inhibitor, and
desipramine, primarily a noradrenergic reuptake inhibitor. Sixteen subjects who stuttered participated in a single-blind placebo, double-blind active
drug crossover study lasting 12 weeks. Speech rate and percent fluency did not significantly improve in placebo compared to baseline. Speech rate significantly increased while repeating, reading or constructing sentences, and during a telephone conversation, but no significant changes in percent fluency were found under
clomipramine compared to placebo. Speech rate during a telephone conversation and percent fluency while speaking in front of an audience of four to seven listeners significantly increased under
clomipramine compared to
desipramine. No significant improvements in percent fluency or speech rate were found for any speaking task under
desipramine compared to placebo. Twelve of 16 subjects reported improved fluency compared to baseline using
clomipramine, whereas 6 reported improvement using
desipramine. Because more evidence of improvement was found under
clomipramine compared to
desipramine, fluency improvement may be related to
clomipramine's greater selectivity for serotonergic reuptake inhibition.