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Study on the Effect of Clozapine and Drug Combination for Patients with Schizophrenia Experiencing First-Line Treatment Failure

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying the effects of a new treatment approach for people with schizophrenia, schizoaffective disorder, or schizophreniform disorder. These are mental health conditions that can affect how a person thinks, feels, and behaves. The study will explore the impact of a six-week intensified medication treatment compared to the usual treatment for individuals who have experienced a first-time treatment failure with their initial medication. The medications being studied include clozapine, ziprasidone, amisulpride (also known as APD421), fluoxetine hydrochloride, perphenazine, paliperidone (also known as 9-hydroxyrisperidone), aripiprazole, promazine hydrochloride, diazepam, sulpiride, pyridoxine hydrochloride, chlorpromazine hydrochloride (also known as aminazine), fluphenazine decanoate, zuclopenthixol, risperidone, flupentixol decanoate (also known as flupenthixol decanoate), lurasidone, sertindole, haloperidol decanoate, pregabalin, brexpiprazole (also known as OPC-34712), cariprazine (also known as RGH-188), and asenapine.

The purpose of the study is to compare the effectiveness of this intensified treatment with the usual treatment in reducing symptoms of these conditions. Participants will receive either the intensified treatment or the usual treatment for six weeks. The study will monitor changes in symptom severity using a tool called the Positive and Negative Syndrome Scale (PANSS), which helps measure the severity of symptoms in these disorders. The study will also look at other aspects such as anxiety, depression, quality of life, and any side effects experienced during the treatment period.

Participants will be observed over a six-week period, during which they will have regular visits to assess their progress. The study aims to provide insights into whether an intensified treatment approach can offer better outcomes for individuals who have not responded well to their initial treatment. This research could help improve treatment strategies for people living with schizophrenia and related disorders.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial visit and consent

    Upon joining the study, the first step involves an initial visit where eligibility is confirmed. This includes verifying age, diagnosis, and current treatment status.

    Written informed consent is required. If necessary, a legal guardian may co-sign. Female participants of childbearing potential must have a negative pregnancy test and agree to use effective contraception during the trial.

  2. Step 2

    Baseline assessment

    A baseline assessment is conducted to evaluate symptom severity using the Positive and Negative Syndrome Scale (PANSS). This scale measures various symptoms associated with schizophrenia.

    Additional assessments may include the Clinical Global Impression Scale (CGI) and the Sheehan Disability Scale (SDS) to determine functional impairment.

  3. Step 3

    Randomization and treatment

    Participants are randomly assigned to one of two groups: the intensified pharmacological treatment group or the treatment as usual group.

    The intensified treatment may involve medications such as ziprasidone, amisulpride, or olanzapine, administered orally. The specific medication, dosage, and frequency will be determined by the study protocol.

  4. Step 4

    Treatment period

    The treatment period lasts for six weeks. During this time, participants continue with their assigned treatment regimen.

    Regular monitoring of symptoms and any side effects is conducted. Participants may be required to visit the study site for assessments and to ensure adherence to the treatment plan.

  5. Step 5

    Final assessment

    At the end of the six-week period, a final assessment is conducted. This includes re-evaluating symptom severity using the PANSS and other relevant scales.

    The study aims to compare changes in symptoms from the baseline to the end of the treatment period between the two groups.

Who can join the trial?

8 criteria

  • Must be an inpatient (staying in a hospital) or outpatient (visiting a hospital or clinic but not staying overnight) between the ages of 18 and 70.
  • Must be willing and able to provide written consent to participate in the study. If you have a legal guardian, they can also sign the consent form with you.
  • If you are a woman who can have children, you must use effective birth control during the study and have a negative pregnancy test at the start of the study.
  • Must have a main diagnosis of schizophrenia, schizoaffective disorder, or schizophreniform disorder as confirmed by a specific interview process.
  • Must currently be experiencing a first-time failure of your initial treatment for the diagnosed condition, meaning the treatment did not work effectively after being used for at least 4 weeks.
  • Must have a score of 3 or higher on the Clinical Global Impression-Improvement scale (CGI-I), which indicates the treatment is not working well.
  • You and your doctor must plan to change your current medication treatment.
  • Must have a certain level of symptom severity and experience difficulties in daily functioning. This means having specific scores on the Positive And Negative Syndrome Scale (PANSS) and the Sheehan Disability Scale (SDS).

Who cannot join the trial?

5 criteria

  • Patients who do not have a diagnosis of schizophrenia, schizoaffective disorder, or schizophreniform disorder cannot participate.
  • Patients who have not experienced a first-time treatment failure on their first-line treatment for the above conditions cannot participate.
  • Patients who are not within the specified age range for the study cannot participate.
  • Patients who are not willing or able to comply with the study procedures cannot participate.
  • Patients who are part of a vulnerable population that the study is not designed to include cannot participate.
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Investigated drugs

Intensified Pharmacological Treatment is a special approach used in this clinical trial to help people with schizophrenia who did not respond well to their first treatment. This treatment involves using a combination of medications that are adjusted and intensified over a six-week period. The goal is to see if this approach can reduce the symptoms of schizophrenia more effectively than the usual treatment methods. The medications used in this intensified treatment are carefully selected and monitored by healthcare professionals to ensure they are safe and effective for the participants.

What is already known about the treatment

Medication for Schizophrenia Treatment – This medication is administered orally in the form of tablets and is currently being studied in clinical trials to assess its effectiveness for individuals with schizophrenia, schizoaffective disorder, or schizophreniform disorder who did not respond to their initial treatment. The main therapeutic use of this medication is to reduce the severity of symptoms associated with these mental health conditions. It works by altering the activity of certain neurotransmitters in the brain, which are chemicals that help transmit signals between nerve cells. This medication is classified as an antipsychotic, which is a type of drug used to manage psychosis, including delusions, hallucinations, and disordered thinking.

Investigated diseases

  • Schizophrenia

    Schizophrenia is a chronic mental disorder characterized by disruptions in thought processes, perceptions, emotional responsiveness, and social interactions. It often manifests with symptoms such as hallucinations, delusions, disorganized thinking, and a lack of motivation. The progression of schizophrenia can vary, with some individuals experiencing episodes of acute symptoms followed by periods of remission. Over time, cognitive functions may decline, affecting memory, attention, and problem-solving abilities. Social withdrawal and reduced emotional expression are common as the disorder progresses. The severity and frequency of symptoms can fluctuate, impacting daily functioning and quality of life.

  • Schizoaffective Disorder

    Schizoaffective disorder is a mental health condition that includes symptoms of both schizophrenia and mood disorders, such as depression or bipolar disorder. Individuals may experience hallucinations, delusions, and disorganized thinking, alongside mood disturbances like depression or mania. The disorder progresses with alternating periods of psychotic symptoms and mood episodes, which can occur simultaneously or separately. Over time, the mood symptoms may become more prominent, affecting emotional stability and social interactions. Cognitive impairments may develop, impacting concentration and decision-making. The course of the disorder can vary, with some individuals experiencing chronic symptoms and others having episodic occurrences.

  • Schizophreniform Disorder

    Schizophreniform disorder is a mental health condition similar to schizophrenia but with a shorter duration of symptoms. It is characterized by hallucinations, delusions, disorganized speech, and abnormal motor behavior. The disorder typically progresses over a period of one to six months, after which symptoms may resolve or transition into schizophrenia or schizoaffective disorder. During the active phase, individuals may experience significant disruptions in daily functioning and social interactions. Cognitive functions such as memory and attention may be temporarily affected. The progression is often marked by acute episodes, with potential for full recovery or development into a more chronic condition.

Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-506602-39-00Protocol codeINTENSIFY SZEstimated enrolment418 patientsSponsorUniversitair Medisch Centrum Utrecht

sourced from the EU Clinical Trials Register and site verification

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).