The goal of this observational study is to investigate the early sensory system in clinical high risk (CHR), first episode psychosis (FEP) individuals and heathly controls. The main questions it aims to answer are:

• Can anomalies in visual and auditory sensory processing serve as early markers of psychosis risk?
• How are these sensory anomalies related to clinical symptom severity and emotional recognition deficits?

Researchers will compare CHR and PEP participants to healthy controls to see if sensory processing differences can help identify individuals at higher risk of developing psychosis.

Participants will:

• Complete behavioral tasks evaluating visual processing (contrast sensitivity, contour integration, facial emotion recognition, visual inference using Necker cubes) and auditory processing (tone-matching, auditory emotion recognition). A temporal perception component will also be assessed within the auditory and emotion recognition tasks, rather than as a separate task.
• Undergo electrophysiological assessments of retinal function using flash stimulation to record retinal potentials (a-wave, b-wave, phNR, oscillatory potentials).
• Provide demographic, clinical, and neuropsychological data during study visits.
• For CHR participants, attend follow-up visits up to 6 months post initial assessments to evaluate psychotic symptom progression.

Inclusion criteria:

All groups:

• Age between 18 and 30 years
• Normal or corrected-to-normal visual acuity
• Affiliated with or dependent on a social security health insurance plan
• Provided informed consent and co-signed the study consent form with the investigator
• Proficient in French

Control group (TEM) specific criteria:

• No current psychiatric disorder (DSM-IV Axis I), except anxiety disorders
• No lifetime history of (hypo)manic episodes or psychotic disorders
• No first-degree family history of schizophrenia spectrum disorders
• No regular use (more than one month continuously) in the past 6 months of the following medications: benzodiazepines, hypnotics, antidepressants, antipsychotics, mood stabilizers, or psychostimulants

Clinical High-Risk (CHR) group specific criteria:

-Meet CHR criteria according to CAARMS: Attenuated positive symptoms (APS) below clinical threshold in intensity or frequency OR Brief Limited Intermittent Psychotic Symptoms (SPLI) OR Genetic Risk

First-Episode Psychosis (PEP) group specific criteria:

-Meet PEP criteria according to CAARMS (psychosis threshold reached)

Exclusion criteria:

• Pregnant, postpartum, or breastfeeding women
• Individuals deprived of liberty by judicial or administrative decision
• Individuals in a life-threatening emergency
• Adults under legal protection measures
• Adults unable to provide consent and not under legal protection
• Impairment that makes participation in the study or understanding of information difficult or impossible
• Alcohol dependence (AUDIT score ≥12 for men, ≥11 for women)
• Current substance use disorder (DAST score >6)
• Cannabis use disorder (CUDIT-R score ≥13)
• History of neurological disorders, including progressive neurological disease
• Progressive retinal disease
• Chronic glaucoma
• Ophthalmologic conditions affecting visual acuity
• Current eye infection
• Hearing disorders affecting auditory acuity

Criteria incompatible with the electroretinographic device:

• Presence of photosensitive epilepsy
• Allergy to components of the electrode gel
• Behavioral problems causing extreme agitation or aggression
• Eye or surrounding tissue lesions that may come into contact with the device