Anxiogenic properties of yohimbine

Abstract

To study the pharmacological induction of stress along with psychological stress and their possible interaction, 20 mg yohimbine and placebo orally were administered to 8 panic patients on placebo treatment, 7 panic patients on alprazolam treatment and 12 controls in a double-blind crossover design. Two structured situations which can be considered as 'neutral' stressors were included: a mental arithmetic task and a continuous performance task. Mental arithmetic induced robust increases in ratings of panicky, anxiety, nervousness, heart rate and electrodermal activity, while the continuous performance task induced increases exclusively in skin conductance reaction. Patients responded to these tasks less than controls with regard to subjective ratings and electrodermal activity. Yohimbine did not potentiate the response to the tasks in the patients. In controls, heart rate during the mental arithmetic task, but not during rest, was increased after yohimbine. In contrast to other yohimbine challenge studies no panic attacks were observed. It is hypothesized that the experimental design together with an instructional set that reduces expectancy factors and the inclusion of structured and time-limited tasks in a challenge paradigm is able to reduce the anxiogenic effects of yohimbine.

Norepinephrine and impulsivity: effects of acute yohimbine

“…The studies differed in doses of yohimbine, order of administration (counterbalanced in this study, progressive in the earlier study), timing of measures (a single post-treatment measure at 90 minutes in the earlier study, instead of serial measures), and in the greater number and frequency of procedures during the current study. Repeated structured non-stressful task performance reduces subjective effects of pharmacologically altered NE (Albus et al 1992;Li et al 2004), consistent with the lack of subjective effects in the present study. Behavioral responses to yohimbine in healthy subjects have varied, with relatively modest effects in controls, especially in low-anxiety subjects (Mizuki et al 1996), and more prominent effects in anxiety disorders (Goddard et al 1995;Gurguis and Uhde 1990) or controls with high baseline anxiety (Mizuki et al 1996).…”

“…Yohimbine was reported to increase autonomic responses to mental arithmetic in controls, but had no interaction with a continuous performance task (Albus et al 1992). Cognitive task administration was reported not to alter salivary MHPG (Li et al 2004).…”