Summary
Quetiapine Fumarate has reached the approved stage (maximum clinical phase 4) for at least one indication, so its use in Schizophrenia would be drug repurposing rather than first-in-human development. This does not mean it is approved for Schizophrenia. ClinicalTrials.gov lists 8 registered trials linking Quetiapine Fumarate to Schizophrenia: 8 have completed. The most advanced is Phase 4 (NCT00325689). The largest enrolment is 550 participants (NCT00234377). Registration activity spans 2002 to 2018. The literature layer holds 8 publications for this pair: 1 Cochrane review, 2 meta-analyses and 5 clinical trial publications. Publication years run from 2003 to 2025. Because at least one synthesis-level source exists (systematic review, meta-analysis or Cochrane review), this pair has been assessed beyond single studies, although the synthesis may concern a different indication.
The RepurpOS disease-intelligence file for Schizophrenia ranks 499 candidate therapeutics from Open Targets, ChEMBL, DGIdb and PubMed; only a minority carry direct clinical evidence, and this page covers one of those. Spontaneous remission context recorded for the condition: Spontaneous full remission rare (<10%); after first episode, ~80% relapse within 5 years without maintenance antipsychotic; functional disability accumulates over time; 20% achieve good long-term outcome.
Evidence table
| Evidence tier | A · Strong |
|---|---|
| Evidence score | 73.0 (trials 30.0, literature 23.0, tier 15, approved bonus 5.0) |
| Registered trials | 8 total: 0 recruiting, 0 active / not yet recruiting, 8 completed, 0 other |
| Linked publications | 8 (5 clinical trial publications, 2 meta-analyses, 1 Cochrane review) |
| Agent type | Drug (Small molecule) |
| Development stage (any indication) | Approved |
| Mechanism / class | Not recorded |
| Data sources | DGIdb |
| Linked via biomarker / target | ADRA1B |
How the evidence score is calculated
- Each registered trial scores by status (recruiting / active / enrolling 3, completed 2.5, not yet recruiting 2, unknown 1, terminated / withdrawn / suspended 0.5) plus a phase bonus (phase 3-4 +2, phase 2 +1, phase 1 +0.5). The trial component is capped at 30.
- Each literature item scores by design (Cochrane review 5, meta-analysis 4, systematic review 3, RCT 3, clinical trial publication 2, curated reference 1.5, other PubMed record 1). The literature component is capped at 30.
- The existing evidence tier adds 15 (A / Strong), 10 (B / Moderate), 5 (C / Preliminary) or 0 (D / Anecdotal).
- Agents approved for any indication (max clinical phase 4) add 5, because an approved agent has an established safety profile that lowers the barrier to repurposing trials.
- The score ranks what has been studied, not what works. It does not read effect sizes or directions of effect.
Registered clinical trials
| NCT ID | Title | Status | Phase | Enrolment |
|---|---|---|---|---|
| NCT01213836 | Compare the Effect on Cognitive Functioning of Two Formulations of Seroquel, Seroquel XR and IR in Patients With Stable Schizophrenia 2010 | completed | Phase 4 | 75 |
| NCT03568500 | A Trial to Explore Acceptance and Performance of Using a Digital Medicine System With Healthcare Professionals and Adults With Schizophrenia, Schizoaffective Disorder, or First Episode Psychosis on an Oral Atypical Antipsychotic 2018 | completed | Phase 4 | 44 |
| NCT00255515 | Seroquel® Combined With Cognitive Remediation Therapy to Conventional Treatment in Patients With Schizophrenia 2005 | completed | Phase 4 | 85 |
| NCT00325689 | Aripiprazole Used as Dual Therapy in the Treatement of Patients With Chronic Stable Schizophrenia or Schizoaffective Disorder. 2006 | completed | Phase 4 | 323 |
| NCT00334035 | Antipsychotic Therapy and First Episode 2003 | completed | Phase 4 | 169 |
| NCT00228462 | Relapse Prevention, RoW: Study to Evaluate Prevention of Relapse in Patients in Stable Chronic Schizophrenia Receiving Either Seroquel or Placebo 2005 | completed | Phase 3 | 197 |
| NCT00234377 | Seroquel Switching Study: Feasibility of Switching Any Antipsychotic Treatment to Seroquel in Patients With Schizophrenia 2004 | completed | Phase 3 | 550 |
| NCT00222495 | A Comparative Study of New Medications for Psychosis in Adolescents 2002 | completed | Not applicable | 30 |
Published literature
- Cochrane review Comparative efficacy and safety of Clozapine vs. Quetiapine in schizophrenia and related disorders: An updated systematic reviewAsenjo-Lobos C, Arancibia M, Garcia-Ribera C et al. · Psychiatry research · 2025 · PMID 41101242
- Meta-analysis Association With Hospitalization and All-Cause Discontinuation Among Patients With Schizophrenia on Clozapine vs Other Oral Second-Generation Antipsychotics: A Systematic Review and Meta-analysis of Cohort StudiesMasuda T, Misawa F, Takase M et al. · JAMA psychiatry · 2019 · PMID 31365048
- Clinical trial publication A 6-week, multicenter, double-blind, double-dummy, chlorpromazine-controlled non-inferiorityrandomized phase iiitrial to evaluate the efficacy and safety of quetiapine fumarate (SEROQUEL) extended-release (XR) in the treatment of patients with schizophrenia and acute episodesLi H, Shen Y, Wang G et al. · Psychiatry research · 2018 · PMID 29040947
- Clinical trial publication Treatment of depressive symptoms in patients with schizophrenia: a randomized, open-label, parallel-group, flexible-dose subgroup analysis of patients treated with extended-release quetiapine fumarate or risperidoneKasper S, Montagnani G, Trespi G et al. · International clinical psychopharmacology · 2015 · PMID 25356632
- Clinical trial publication Efficacy and safety of extended-release quetiapine fumarate in youth with bipolar depression: an 8 week, double-blind, placebo-controlled trialFindling RL, Pathak S, Earley WR et al. · Journal of child and adolescent psychopharmacology · 2014 · PMID 24956042
- Clinical trial publication Extended-release quetiapine fumarate (quetiapine XR) versus risperidone in the treatment of depressive symptoms in patients with schizoaffective disorder or schizophrenia: a randomized, open-label, parallel-group, flexible-dose studyDi Fiorino M, Montagnani G, Trespi G et al. · International clinical psychopharmacology · 2014 · PMID 24681810
- Clinical trial publication Pharmacokinetics and tolerability of extended-release quetiapine fumarate in Han Chinese patients with schizophreniaLi Q, Su YA, Liu Y et al. · Clinical pharmacokinetics · 2014 · PMID 24385309
- Meta-analysis Improvement without impairment: a review of clinical data for quetiapine in the treatment of schizophreniaTandon R · Journal of clinical psychopharmacology · 2003 · PMID 12832945
Mechanism and notes
No mechanism of action is recorded for this pair in the source databases.
OSMF's existing evidence tier for this pair is A (Strong), derived from the strength of the disease association recorded in DGIdb, in this case via the biomarker or target ADRA1B. The tier describes how well the drug-disease link is documented, not how well the drug works.
Frequently asked questions
Is Quetiapine Fumarate approved for Schizophrenia?
Quetiapine Fumarate has reached the approved stage (maximum clinical phase 4) for at least one indication, so its use in Schizophrenia would be drug repurposing rather than first-in-human development. This does not mean it is approved for Schizophrenia. Approval status for the specific indication should always be confirmed with the relevant regulator and prescribing information.
Is Quetiapine Fumarate in clinical trials for Schizophrenia?
ClinicalTrials.gov lists 8 registered trials linking Quetiapine Fumarate to Schizophrenia: 8 have completed. The most advanced is Phase 4 (NCT00325689). The largest enrolment is 550 participants (NCT00234377). Registration activity spans 2002 to 2018.
What does the evidence show for Quetiapine Fumarate in Schizophrenia?
Quetiapine Fumarate has both completed registered trials and synthesis-level publications linked to Schizophrenia. That is the strongest profile in this database, but the summaries here do not extract effect sizes, so read the linked reviews for direction and magnitude of benefit. OSMF's existing evidence tier for this pair is A (Strong), derived from the strength of the disease association recorded in DGIdb, in this case via the biomarker or target ADRA1B. The tier describes how well the drug-disease link is documented, not how well the drug works.
Cite this page
Data: ClinicalTrials.gov, PubMed, Open Targets, ChEMBL, DGIdb and the OSMF therapeutic agent database. Last updated 2026-07-05. Page built 2026-10-07.