RationaleAyahuasca is a psychotropic plant tea from South America used for religious purposes by indigenous people of the Amazon. Increasing evidence indicates that ayahuasca may have therapeutic potential in the treatment of mental health disorders and can enhance mindfulness-related capacities. Most research so far has focused on acute and sub-acute effects of ayahuasca on mental health-related parameters and less on long-term effects.ObjectivesThe present study aimed to assess sub-acute and long-term effects of ayahuasca on well-being and cognitive thinking style. The second objective was to assess whether sub-acute and long-term effects of ayahuasca depend on the degree of ego dissolution that was experienced after consumption of ayahuasca.ResultsAyahuasca ceremony attendants (N = 57) in the Netherlands and Colombia were assessed before, the day after, and 4 weeks following the ritual. Relative to baseline, ratings of depression and stress significantly decreased after the ayahuasca ceremony and these changes persisted for 4 weeks. Likewise, convergent thinking improved post-ayahuasca ceremony up until the 4 weeks follow-up. Satisfaction with life and several aspects of mindfulness increased the day after the ceremony, but these changes failed to reach significance 4 weeks after. Changes in affect, satisfaction with life, and mindfulness were significantly correlated to the level of ego dissolution experienced during the ayahuasca ceremony and were unrelated to previous experience with ayahuasca.ConclusionIt is concluded that ayahuasca produces sub-acute and long-term improvements in affect and cognitive thinking style in non-pathological users. These data highlight the therapeutic potential of ayahuasca in the treatment of mental health disorders, such as depression.

Background 5-methoxy-N,N-dimethyltryptamine (hereinafter referred to as 5-MeO-DMT) is a psychedelic substance found in the secretion from the parotoid glands of the Bufo alvarius toad. Inhalation of vapor from toad secretion containing 5-MeO-DMT has become popular in naturalistic settings as a treatment of mental health problems or as a means for spiritual exploration. However, knowledge of the effects of 5-MeO-DMT in humans is limited. Aims The first objective of this study was to assess sub-acute and long-term effects of inhaling vapor from dried toad secretion containing 5-MeO-DMT on affect and cognition. The second objective was to assess whether any changes were associated with the psychedelic experience. Methods Assessments at baseline, within 24 h and 4 weeks following intake, were made in 42 individuals who inhaled vapor from dried toad secretion at several European locations. Results Relative to baseline, ratings of satisfaction with life and convergent thinking significantly increased right after intake and were maintained at follow-up 4 weeks later. Ratings of mindfulness also increased over time and reached statistical significance at 4 weeks. Ratings of depression, anxiety, and stress decreased after the session, and reached significance at 4 weeks. Participants that experienced high levels of ego dissolution or oceanic boundlessness during the session displayed higher ratings of satisfaction with life and lower ratings of depression and stress. Conclusion A single inhalation of vapor from dried toad secretion containing 5-MeO-DMT produces sub-acute and long-term changes in affect and cognition in volunteers. These results warrant exploratory research into therapeutic applications of 5-MeO-DMT. Electronic supplementary material The online version of this article (10.1007/s00213-019-05236-w) contains supplementary material, which is available to authorized users.

Using scripts, previous studies by Christianson and co-workers have suggested that simulating amnesia undermines memory. Relying on a more realistic mock crime paradigm, the current study examined whether feigning amnesia has memory-undermining effects. After committing a mock crime, one group of participants (n ¼ 21) was instructed to simulate amnesia for the event. Their performance on immediate free recall tests was compared to that of participants (n ¼ 20) who were instructed to respond honestly during free recall. After one week, simulators, honestly responding controls, and a second control group (n ¼ 20) that had not undergone immediate memory testing after the pertinent event completed free recall tests. This time, all participants were instructed to perform as well as they could.At the follow-up free recall test, both ex-simulators and controls who underwent the memory testing for the first time performed significantly worse than the honestly responding controls. Thus, the current study supports the idea that simulating amnesia in order to evade responsibility for a crime has detrimental effects on true memory of the crime. Our results also suggest that this effect can best be understood in terms of lack of rehearsal.

This field study investigated to what extent memory of criminally relevant details is affected at (close to) zero (M BAC = 0.00%), moderate (M BAC = 0.06%), and high (M BAC = 0.16%) levels of alcohol intoxication. Participants (N = 76) were approached in bars and were invited to watch a mock crime from a perpetrator perspective. We also measured their blood alcohol concentration levels. After 3-5 days, when participants were sober, they underwent a free and cued recall task about the mock crime. Compared with sober controls, both moderately and highly intoxicated individuals were less complete when recollecting crime details, recalling up to 33% fewer correct details. Overall, intoxicated participants were less accurate during the cued recall task (i.e. they produced more errors) relative to sober participants. These accuracy effects were dose-dependent for cued recall of salient features. Implications for police interrogations of defendants are discussed.

Defendants and witnesses are often intoxicated by alcohol. We investigated whether memory and resistance to suggestive cues are undermined at blood alcohol concentrations (BACs) that were (close to) zero (M BAC = 0.01%), moderate (M BAC = 0.06%), or high (M BAC = 0.16%). Participants (N = 67) were approached in bars and instructed to commit a mock crime. Immediately after this, their memory and susceptibility to suggestive questions were tested, and these were re-tested during a sober follow-up 3-5 days later. Compared with sober participants, moderate and severe intoxication was associated with lower levels of correctly recalled crime details during both test sessions (i.e. intoxicated and sober). Also, during both sessions, severely intoxicated participants displayed a greater tendency to go along with suggestive cues compared with sober participants. Thus, intoxication impaired memory and increased suggestibility during an immediate interview, and both effects persisted when sober again.