Summary
Olanzapine has reached the approved stage (maximum clinical phase 4) for at least one indication, so its use in ADHD would be drug repurposing rather than first-in-human development. This does not mean it is approved for ADHD. ClinicalTrials.gov lists 4 registered trials linking Olanzapine to ADHD: 1 is currently recruiting; 2 have completed; 1 is terminated, withdrawn, suspended or of unknown status. The most advanced is Phase 4 (NCT01000402). The largest enrolment is 5000 participants (NCT01246765). Registration activity spans 2006 to 2010. The literature layer holds 8 publications for this pair: 2 Cochrane reviews, 1 meta-analysis, 1 systematic review and 4 clinical trial publications. Publication years run from 1998 to 2023. 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 Attention Deficit-Hyperactivity Disorder ranks 305 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 remission by adulthood: 30-70% symptom reduction (depending on definition); functionally impairing ADHD persists into adulthood in 50-65% of childhood cases; DSMIV criteria met in adulthood in ~50%.
Evidence table
| Evidence tier | A · Strong |
|---|---|
| Evidence score | 58.0 (trials 13.0, literature 25.0, tier 15, approved bonus 5.0) |
| Registered trials | 4 total: 1 recruiting, 0 active / not yet recruiting, 2 completed, 1 other |
| Linked publications | 8 (4 clinical trial publications, 2 Cochrane reviews, 1 meta-analysis, 1 systematic review) |
| Agent type | Drug (Small molecule) |
| Development stage (any indication) | Approved |
| Mechanism / class | Not recorded |
| Data sources | DGIdb |
| Linked via biomarker / target | ADRA2C |
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trial scores by status (recruiting / active / enrolling 3, completed 2.5, not yet recruiting 2, unknown 1, terminated / withdrawn / suspended 0.5) plus a phase bonus (phase 3-4 +2, phase 2 +1, phase 1 +0.5).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 |
|---|---|---|---|---|
| NCT00205699 | Metabolic Effects of Antipsychotics in Children 2006 | completed | Phase 4 | 144 |
| NCT01000402 | Juvenile Bipolar Disorder Outpatient Program 2008 | status unknown | Phase 4 | 150 |
| NCT01057329 | Therapeutic Drug Monitoring in Child and Adolescent Psychiatry 2010 | completed | Not applicable | 200 |
| NCT01246765 | National Pregnancy Registry for Psychiatric Medications 2008 | recruiting | Not applicable | 5,000 |
Published literature
- Cochrane review Comparative efficacy, tolerability, and acceptability of pharmacological interventions for the treatment of children, adolescents, and young adults with Tourette's syndrome: a systematic review and network meta-analysisFarhat LC, Behling E, Landeros-Weisenberger A et al. · The Lancet. Child & adolescent health · 2023 · PMID 36528030
- Meta-analysis Association of Antipsychotic Drug Exposure in Pregnancy With Risk of Neurodevelopmental Disorders: A National Birth Cohort StudyStraub L, Hernández-Díaz S, Bateman BT et al. · JAMA internal medicine · 2022 · PMID 35343998
- Clinical trial publication Combination use of atomoxetine hydrochloride and olanzapine in the treatment of attention-deficit/hyperactivity disorder with comorbid disruptive behavior disorder in children and adolescents 10-18 years of ageHolzer B, Lopes V, Lehman R · Journal of child and adolescent psychopharmacology · 2013 · PMID 23952189
- Systematic review Summary of the comparative effectiveness review on off-label use of atypical antipsychoticsMaher AR, Theodore G · Journal of managed care pharmacy : JMCP · 2012 · PMID 22784311
- Cochrane review PubMed record PMID 22132426Maglione M, Maher AR, Hu J et al. · 2011
- Clinical trial publication Lack of effect of stimulant combination with second-generation antipsychotics on weight gain, metabolic changes, prolactin levels, and sedation in youth with clinically relevant aggression or oppositionalityPenzner JB, Dudas M, Saito E et al. · Journal of child and adolescent psychopharmacology · 2009 · PMID 19877981
- Clinical trial publication Effectiveness and tolerability of open label olanzapine in children and adolescents with Tourette syndromeMcCracken JT, Suddath R, Chang S et al. · Journal of child and adolescent psychopharmacology · 2008 · PMID 18928414
- Clinical trial publication Open-label olanzapine treatment in five preadolescent childrenKrishnamoorthy J, King BH · Journal of child and adolescent psychopharmacology · 1998 · PMID 9730076
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 ADRA2C. The tier describes how well the drug-disease link is documented, not how well the drug works.
Frequently asked questions
Is Olanzapine approved for ADHD?
Olanzapine has reached the approved stage (maximum clinical phase 4) for at least one indication, so its use in ADHD would be drug repurposing rather than first-in-human development. This does not mean it is approved for ADHD. Approval status for the specific indication should always be confirmed with the relevant regulator and prescribing information.
Is Olanzapine in clinical trials for ADHD?
ClinicalTrials.gov lists 4 registered trials linking Olanzapine to ADHD: 1 is currently recruiting; 2 have completed; 1 is terminated, withdrawn, suspended or of unknown status. The most advanced is Phase 4 (NCT01000402). The largest enrolment is 5000 participants (NCT01246765). Registration activity spans 2006 to 2010.
What does the evidence show for Olanzapine in ADHD?
Olanzapine has both completed registered trials and synthesis-level publications linked to ADHD. 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 ADRA2C. 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.