Overview

The goal of this clinical trial is to learn how tests undertaken by people at high risk of developing psychosis (aged 17 to 30 years old) change when those people are given the study drug MT1988 daily for 8 weeks. This will help identify tests that could be used in later trials developing treatments for symptoms in people at high risk of developing psychosis, to measure whether those new treatments are effective.

The main question this trial aims to answer is:

Can any of the tests (biomarkers) used in this study detect changes in participants dosed with one of two different dose levels of MT1988?

Researchers will compare the results from two dose levels of MT1988 to a placebo group. Researchers do not expect to see the test results change in participants taking placebo and this will be compared to changes expected in test results in participants taking MT1988.

Participants will:

• take a dose of MT1988 or placebo twice per day for 8 weeks
• attend clinic appointments every two weeks to undertake assessments
• report any side effects they experience to the researchers

Eligibility

Inclusion Criteria:

• Aged 17 to 30 years at time of consent.
• Capacity to provide informed consent. (For patients under 17 years, participants must assent and informed consent provided by one parent or legal guardian).
• Meet diagnostic criteria for Clinical High Risk of Psychosis (CHR).
• For females of reproductive potential - not pregnant or nursing and willing to comply with contraceptive requirements.

Exclusion Criteria:

• Clinically significant medical disorder or laboratory test abnormality at Day 1.
• History of or current condition which may prevent participant from complying with study procedures.
• Past or current schizophrenia, other disorder with symptoms of psychosis, major cognitive disorder resulting from traumatic brain injury.
• Received antipsychotic medication equivalent to a total lifetime haloperidol dose \>50 mg.
• Current use of medications which could interfere with the study endpoints - to be assessed by the Investigator at screening.
• Unable to abstain from nicotine (e.g. cigarettes, vape) for two hours before cognitive testing.
• Unable to abstain from marijuana use on test day prior to test completion.
• History of suicide attempt or behavior in previous 12 months, or risk of suicidal behavior during the study.