OPEN Foundation

Day: 11 May 2016

Ketamine: stimulating antidepressant treatment?

Abstract

The appeal of ketamine – in promptly ameliorating depressive symptoms even in those with non-response – has led to a dramatic increase in its off-label use. Initial promising results await robust corroboration and key questions remain, particularly concerning its long-term administration. It is, therefore, timely to review the opinions of mood disorder experts worldwide pertaining to ketamine’s potential as an option for treating depression and provide a synthesis of perspectives – derived from evidence and clinical experience – and to consider strategies for future investigations.

Malhi, G. S., Byrow, Y., Cassidy, F., Cipriani, A., Demyttenaere, K., Frye, M. A., … & McShane, R. (2016). Ketamine: stimulating antidepressant treatment?. British Journal of Psychiatry Open, 2(3), e5-e9. 10.1192/bjpo.bp.116.002923
Link to full text

Effects of low dose ibogaine on subjective mood state and psychological performance

Abstract

Ethnopharmacological relevance: Root bark from Tabernanthe iboga has been used traditionally in West Africa as a psychoactive substance in religious rituals. In smaller doses it is reported anecdotally to have stimulant properties.

Aim of the study: To evaluate the influence of a single 20 mg ibogaine dose on psychological variables reflecting subjective mood state and a range of cognitive functions.

Materials and methods: 21 healthy male volunteers received single 20 mg doses of ibogaine after 6 days pretreatment with double-blind paroxetine or placebo. We compared responses to a battery of psychometric tests and subjective mood ratings performed before and 2 h after ibogaine dosing, and assessed relationships between changes in test scores and concentrations of active moiety (the sum of molar noribogaine and ibogaine concentrations). Psychological tests were chosen based on responsiveness to opioid and serotonergic ligands.

Results: Ibogaine had minimal influence on psychological tests and mood ratings. The ability to selectively ignore distracting spatial information showed some evidence of modulation; however because this effect was limited to the less challenging condition calls into question the reliability of this result.

Conclusion: We were unable to identify stimulant effects after single 20 mg doses of ibogaine. Future research is needed to confirm whether active moiety concentrations impact selective attention abilities while leaving other cognitive functions and mood state unaffected.

Forsyth, B., Machado, L., Jowett, T., Jakobi, H., Garbe, K., Winter, H., & Glue, P. (2016). Effects of low dose ibogaine on subjective mood state and psychological performance. Journal of Ethnopharmacology. http://dx.doi.org/10.1016/j.jep.2016.05.022

Link to full text