Study overview 

This page contains comprehensive information regarding the structure and schedule of our clinical trial.

It is important to be aware of the long duration of this study, which requires sustained motivation and commitment throughout the study program.

Study type

A clinical trial is designed to make sure the results are scientifically reliable, repeatable, comparable, and trustworthy when studying how safe and effective the new treatment is.

Multi-center, two-arm, parallel-group, double-blind, randomized, placebo-controlled phase II add-on clinical trial.

What does this mean?

  • Multi-center means that the trial will be conducted across multiple locations.

  • Two-arm, parallel-group means that the trial will have two groups (arms) of participants who receive different treatments, and the participants in each group will be studied at the same time (in parallel).

  • Double-blind means that neither the participants nor the researchers administering the treatment will know who is receiving the active treatment or a placebo (the identical looking drug that does not contain the pharmacologically active compound).

  • Randomized means that participants will be randomly assigned to one of the two groups.

  • Placebo-controlled means that the study will compare the effects of the active treatment to the effects of the placebo.

What to expect?

Total study duration: 12 months

Number of study visits:10 times (at the clinic)

3 phases in the study

Treatment phase

Months 1 to 6

Intake of CBD or placebo as capsules in addition to your individual standard antipsychotic therapy. 

Tapering off

Lasting 2 weeks

The additional medication (CBD or placebo) is gradually discontinued.

Follow up

Months 7 to 12

Intake of your individual standard antipsychotic
therapy only. 

12 months

Am I elegible to participate?

Before deciding to participate in a clinical trial, you should look carefully at the trial’s inclusion and exclusion criteria.

Key inclusion criteria

  • Informed consent given by the participant.

  • DSM-IV-TR diagnosis of schizophrenic psychosis (295.10, 295.20, 295.30, 295.90)

  • A stable oral therapy with

    • amisulpride,

    • aripiprazole,

    • olanzapine,

    • paliperidone,

    • quetiapine,

    • or risperidone

      (TAU: treatment as usual) for at least two weeks prior to inclusion in the study to ensure that the maximum effect of the previous medication has been received.

  • First documented diagnosis of schizophrenia must not be older than fifteen years.

  • Age 18 to 65 years, male or female.

  • Initial PANSS total score of ≤ 75 at baseline.

  • Female participants of childbearing potential need to utilize a reliable method of contraception. 

  • Body Mass Index between 18 and 40.

  • Fluent in English or German.

Key exclusion criteria

  • Lack of accountability (assessed by an independent psychiatrist).

  • Treatment-resistant schizophrenia diagnosis.

  • Taking long-lasting antipsychotic medicines (depot).

  • Positive urine drug-screening for illicit drugs at screening (except cannabinoids and benzodiazepines).

  • Serious suicidal risk at screening visit (subject to investigator’s judgment).

  • Other relevant interferences of axis 1 (e.g., serious depression).

  • Other relevant neurological or medical disorders.

  • Pregnancy or nursing (i.e., lactation).

Interested in participating?

Your contribution can help shape the future of healthcare. Take part in our clinical trial and play a vital role in advancing medical knowledge. If you are interested, please use our contact form.