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D. Zanchi

Acute effects of methylphenidate, modafinil and MDMA on negative emotion processing

December 1, 2017 / MDMA, Papers, Psychology, Publications / By / , , , , ,

Abstract

BACKGROUND:
Stimulants such as methylphenidate (MPH) and modafinil are frequently used as cognitive enhancers in healthy people, whereas 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) is proposed to enhance mood and empathy in healthy subjects. However, comparative data on the effects of MPH and modafinil on negative emotions in healthy subjects have been widely missing. The aim of this study was to compare the acute effects of MPH and modafinil on the neural correlates of fearful face processing using MDMA as a positive control.
METHODS:
Using a double-blind within-subject placebo-controlled cross-over design, 60 mg MPH, 600 mg modafinil, and 125 mg MDMA were administrated to 22 healthy subjects, while performing an event-related fMRI task to assess brain activation in response to fearful faces. Negative mood states were assessed with the State-Trait Anxiety Inventory and subjective ratings.
RESULTS:
Relative to placebo, modafinil, but not MPH or MDMA, increased brain activation within a limbic-cortical-striatal-pallidal-thalamic circuit during fearful face processing. Modafinil but not MPH also increased amydgala responses to fearful faces compared with MDMA. Furthermore, activation in the middle and inferior frontal gyrus in response to fearful faces correlated positively with subjective feelings of fearfulness and depressiveness after modafinil administration.
CONCLUSIONS:
In spite of the cognitive enhancement effects of 600 mg modafinil in healthy people, potential adverse effects on emotion processing should be considered.
Schmidt, A., Müller, F., Dolder, P. C., Schmid, Y., Zanchi, D., Egloff, L., … & Borgwardt, S. (2017). Acute effects of methylphenidate, modafinil and MDMA on negative emotion processing. International Journal of Neuropsychopharmacology, pyx112. 10.1093/ijnp/pyx112
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Acute LSD effects on response inhibition neural networks

October 2, 2017 / LSD, Neuroscience, Papers, Psychology, Publications / By / , , , , , ,

Abstract

BACKGROUND:
Recent evidence shows that the serotonin 2A receptor (5-hydroxytryptamine2A receptor, 5-HT2AR) is critically involved in the formation of visual hallucinations and cognitive impairments in lysergic acid diethylamide (LSD)-induced states and neuropsychiatric diseases. However, the interaction between 5-HT2AR activation, cognitive impairments and visual hallucinations is still poorly understood. This study explored the effect of 5-HT2AR activation on response inhibition neural networks in healthy subjects by using LSD and further tested whether brain activation during response inhibition under LSD exposure was related to LSD-induced visual hallucinations.
METHODS:
In a double-blind, randomized, placebo-controlled, cross-over study, LSD (100 µg) and placebo were administered to 18 healthy subjects. Response inhibition was assessed using a functional magnetic resonance imaging Go/No-Go task. LSD-induced visual hallucinations were measured using the 5 Dimensions of Altered States of Consciousness (5D-ASC) questionnaire.
RESULTS:
Relative to placebo, LSD administration impaired inhibitory performance and reduced brain activation in the right middle temporal gyrus, superior/middle/inferior frontal gyrus and anterior cingulate cortex and in the left superior frontal and postcentral gyrus and cerebellum. Parahippocampal activation during response inhibition was differently related to inhibitory performance after placebo and LSD administration. Finally, activation in the left superior frontal gyrus under LSD exposure was negatively related to LSD-induced cognitive impairments and visual imagery.
CONCLUSION:
Our findings show that 5-HT2AR activation by LSD leads to a hippocampal-prefrontal cortex-mediated breakdown of inhibitory processing, which might subsequently promote the formation of LSD-induced visual imageries. These findings help to better understand the neuropsychopharmacological mechanisms of visual hallucinations in LSD-induced states and neuropsychiatric disorders.
Schmidt, A., Müller, F., Lenz, C., Dolder, P. C., Schmid, Y., Zanchi, D., … & Borgwardt, S. (2017). Acute LSD effects on response inhibition neural networks. Psychological Medicine, 1-13. 10.1017/S0033291717002914
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