### **Psychedelic drug use and schizotypy in non-clinical population**
*[HUD]*
<br />
The project aims to investigate whether history of psychedelic drug use in healthy non-clinical population is associated with higher schizotypy scores.
It incorporates a cross-sectional study design and tests the following **Primary Hypotheses**:
1. Subjects with reported history of psychedelic use on average tend to score higher on schizotypy
(significant effect of the history of psychedelic use on "schizotypy" in a general linear model accounting for the use of alcohol, tobacco, opiates and stimulants)
2. The afore-mentioned relationship is moderated by the personality trait openness (i.e. there is a stronger correlation between Openness and Schizotypy in those with the history of psychedelic use [Investigated interaction contrast: Schizotypy ~ Openness x PsychedelicUse])
**Secondary Hypotheses**:
3. Subjects with the history of psychedelic use have noisier aversive learning curves;
4. Subjects with the history of psychedelic use are less influenced by explicit information about rule reversals compared to their counterparts without history of psychedelic use
5. Initial expected values (proportional to fear responses) prior to receiving unconditioned stimuli are more asymmetric in psychedelic users in the instructed runs;
6. Subjects with the history of psychedelic use exhibit elevated tendency for false perceptions in the illusion of motion task;
7. Subjects with the history of psychedelic use exhibit elevated tendency for bias against disconfirmatory evidence (BADE);
8. Recent and more frequent use of psychedelics is associated with more marked abnormalities in the afore-mentioned traits (noisier learning, lower sensitivity to instructed reversals, larger asymmetry of initial expected values of the stimuli, higher tendency toward false perception of motion, larger BADE scores).
**Primary Endpoints**:
* Composite schizotypy Z-score merging effects of the two scales:
- Peters Delusion Ideation inventory (PDI)
- Short Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE)
* Personality trait Openness.
**Secondary Endpoints**:
* Learning rate
* ρ-parameter defining effects of instructed knowledge
* Difference in initial expected values of the stimuli (ΔEV = EVA - EVB)
* Variance of EVs (expected values)
* Motion perception accuracy
* BADE plausibility scores
(Secondary endpoints are parameters extracted from the modified Rescorla-Wagner model similar to the one used in [Atlas et al., 2016] [1])
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#### **Links :**
1. [Atlas et al., 2016][1]
2. [Lebedev-Garzon-Almeida implementation of the Hybrid Rescorla-Wagner Model][2]
('RW_instr_multipleSubj_initFree.stan')
[1]: https://elifesciences.org/articles/15192
[2]: https://github.com/alex-lebedev/ILDPII/tree/master/stan_models
