Ludewig S et al. No lasting effects of moderate doses of MDMA (Ecstasy) on memory performance and mood states in healthy humans, San Francisco

MDMA (3,4-methylenedioxymethamphetamine) or ”Ecstasy” is a phenylethylamine with structural similarities to both classic hallucinogens such as mescaline and stimulants such as amphetamine. MDMA mainly releases serotonin (5-HT) and to a lesser extent, dopamine. Healthy MDMA naive humans performed similarly on Spatial Span, Pattern Recognition Memory, Spatial Working Memory tasks and showed no significant alterations in mood states two weeks before and following the administration of two moderate doses of MDMA.In view of the literature, this is the first controlled study investigating the mid-term effects of two moderate doses of 3,4 methylenedioxymeth-amphetamine (MDMA, ”Ecstasy”) on visual and working memory performance and mood states in humans.  Healthy MDMA naive humans performed similarly on visual and working memory tests and showed no significant alterations in anxious and depressive mood states two weeks before and following the administration of MDMA.  These data suggest that two moderate doses of MDMA do not alter significantly memory performance as well as affective states in healthy volunteers.    Thanks to Bob Wallace, Microsoft

Ludewig S, et al. Investigation into the effects of the 5-HT2A agonist psilocybin in oc-

spectrum disorders Proposal, HRI California

Several studies suggest a role for serotonin (5-HT) in the aetiology and pathogenesis of oc-spectrum disorders (OCSD) such as obsessive compulsive disorders (OCD), eating and somatoform disorders.  Serotonin dysfunctions also could contribute to obsessive behaviors, dysphoric mood and impulse dyscontrol in oc-spectrum disorders.  This view is supported by the partial efficacy of serotonin enhancing drugs in the treatment of OCD and related disorders such as anorexia nervosa (AN), bulimia nervosa (BN) and somatoform disorders (SD).  Psilocybin, a serotonin 5-HT2A agonist, induces in a medium dosage a generally well controllable altered state of consciousness characterized by changes in sensory perception, affect and mood, thought processes, and ego-functioning.  There is some evidence from numerous studies indicating that Psilocybin alters self-perception and activates different emotional states.  An abnormal self-perception of figure and weight, decreased self-control such as impulse dyscontrol and obsessive behaviors, and decreased value of self-confidence are common features of OCSD.  The involvement of 5-HT and specifically the 5-HT receptors functioning in the aetiology and pathogenesis of OCD, AN, BN and SD supports our hypothesis: that Psilocybin contributes to alterations in psychological factors and may exert beneficial effects in patients suffering from these disorders.  The primary aim of the proposed project is to investigate the effects of a single moderate dose of Psilocybin on psychological factors involved in OCSD.  If we are able to demonstrate beneficial effects of Psilocybin on immediate behavior or the course of OCSD in this pilot study, we suggest to conduct further studies investigating the repeated administration of Psilocybin in OCSD.

Ludewig S, et al. The acoustic startle reflex and its modulation

The startle reflex and its modulation by prepulse inhibition (PPI) and habituation are used in many studies in different fields of neuropsychiatric research.  The aim of this study was to examine the effects of age and gender on PPI, startle magnitude, and habituation in healthy human volunteers.  Twenty-seven male and twenty-eight female participants of four different age groups (range: 20-60 years) were investigated in an acoustic startle paradigm using a stimulus of 115 dB and a prepulse of 86 dB (16 dB over the white noise) with five different prepulse conditions (pp30, pp60, pp120, pp240, and pp2000); seventeen males and sixteen female participants were tested three times at  monthly intervals. Aged participants showed significantly lower startle magnitude and significantly more habituation than younger participants (see figure), but there was no effect of age on PPI.  Moreover, there were no effects of gender on startle reactivity, PPI, or habituation measures.  Healthy males and females exhibited stable startle magnitudes and PPI across sessions. Startle magnitude and habituation are age-dependent measures, which is important to note for matching strategies. Furthermore, the results demonstrated that PPI and startle are reliable measures of sensory information processing in both genders.  

Ludewig S, et al. Decision-making strategies by panic disorder subjects are more sensitive to errors

Decision-making is a complex process, which can be assessed experimentally by the two-choice prediction task. Error-rate, i.e. the frequency of incorrect predictions during this task, is an important factor for the response selection during decision-making. This investigation examined whether the frequency of incorrect predictions has an augmented effect on the number of different strategies underlying decision-making in humans with panic disorder. At 20% error-rates, panic disorder subjects when compared to MDD and C subjects generated more strategies and switched more frequently between strategies as measured by the dynamical entropy and the range of local dynamical entropies. Response bias measures during the two-choice prediction task and post-test selfassessment did not differ between panic disorder subjects and MDD or C subjects. Panic disorder subjects show uniformly high response sequence unpredictability in the presence of low error-rates, which is consistent with continued search for an optimal response strategy even when the error-rate is low.