A Prospective Cohort Study to Assess Clinical Effectiveness of an Investigational Digital Therapeutic (CT-155) in Patients With Experiential Negative Symptoms of Schizophrenia

Open to people ages 18 years and up

1. Has a primary diagnosis of schizophrenia using the diagnostic criteria for schizophrenia as defined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5 TR), and/or International Classification of Disease-10 (ICD-10) diagnosis code consistent with a schizophrenia diagnosis.
2. Has a Clinical Global Impression - Schizophrenia (CGI-SCH) negative symptoms score (item #2) ≥ 4 (moderately ill) at Screening.
3. 18 years of age or older at the time of informed consent.
4. Is willing and able to use CT-155 in English language regularly, to provide written informed consent to participate in the study and to be compliant with study-related assessments and activities.
5. Has outpatient treatment status at the time of screening, with no inpatient treatment for schizophrenia within 12 weeks prior to Screening.
6. Is on an antipsychotic medication(s) for at least 12 weeks prior to study entry.
7. Is the sole user of an iPhone with an iPhone operating system (iOS) 16+ or a smartphone with an Android operating system (OS) 12+ with a United States telephone number, and is willing to download and use the specified digital mobile application required by the protocol.
8. Is willing and able to receive SMS text messages and push notifications on their smartphone.

Further inclusion criteria apply.

1. Has a score of ≥3 (mildly ill) for CGI-SCH positive symptoms (item #1) at Screening.
2. Has active substance use disorder of any severity in the last 3 months, other than caffeine and nicotine. Patients are excluded if they fulfill criteria for moderate or severe substance use disorder for cannabis. Only mild substance use disorder for cannabis is allowed if considered by investigator to not impact ability of the patient to participate in the study.

3. Has suicidal ideation or behavior, as assessed by the Columbia Suicide Severity

   Rating Scale (C-SSRS):

   • Patients with a "yes" response to either Items #4 or #5 on the C-SSRS Suicidal Ideation Item within the last 3 months (12 weeks) prior to screening, or at Screening.
   • Patients with a "yes" response on the C-SSRS Suicidal Behavior Items within the last 6 months (26 weeks) prior to screening or at Screening.
4. Patients who, in the opinion of the investigator, present a risk of suicide.
5. Is currently enrolled or has participated in the last 3 months (12 weeks) in a mental health related clinical study (interventional or observational).
6. Has participated in previous studies of CT-155 or CT-156.