Clinical trials data
Cognitive tests in depression and bipolar disorder trials: 1,247 registered studies
Every registered depression and bipolar disorder study on ClinicalTrials.gov that names a cognitive test in an outcome measure: the tests used most, how often as a primary outcome, which tests go together, how large the studies are and when they measure the outcome.
- Registered depression and bipolar disorder studies name a cognitive test in an outcome
- 1,247
- Led by industry
- 69
The tests depression and bipolar disorder trials use most
The Trail Making Test leads: 204 of the 1,247 studies name it, 16%. Next comes Verbal Learning (178). As a primary outcome, the Trail Making Test leads with 52 studies.
- 1
Trail Making Test204 studies, 52 as a primary outcome
- 2
Verbal Learning178 studies, 51 as a primary outcome
- 3
Verbal Fluency154 studies, 43 as a primary outcome
- 4
Digit Span Test143 studies, 44 as a primary outcome
- 5
Symbol Coding143 studies, 37 as a primary outcome
- 6
Stroop Color-Word Test138 studies, 38 as a primary outcome
- 7
Go/No-Go Task79 studies, 33 as a primary outcome
- 8
N-Back Task79 studies, 28 as a primary outcome
- 9
Continuous Performance Test73 studies, 27 as a primary outcome
- 10
Card Sorting Test (Berg)65 studies, 16 as a primary outcome
- 11
Category Fluency41 studies, 13 as a primary outcome
- 12
Monetary Incentive Delay40 studies, 27 as a primary outcome
- 13
Choice Reaction Time36 studies, 10 as a primary outcome
- 14
Effort for Rewards Task35 studies, 15 as a primary outcome
- 15
Eriksen Flanker Task33 studies, 17 as a primary outcome
- 16
Emoji Emotion Recognition33 studies, 11 as a primary outcome
- 17
Dot-Probe Task33 studies, 10 as a primary outcome
- 18
Tower Planning29 studies, 9 as a primary outcome
- 19
Short Story Recall27 studies, 9 as a primary outcome
- 20
Probabilistic Reward Task25 studies, 14 as a primary outcome
- 21
Rapid Visual Information Processing25 studies, 10 as a primary outcome
- 22
Implicit Association Test (IAT)24 studies, 2 as a primary outcome
- 23
AX Continuous Performance Test23 studies, 6 as a primary outcome
- 24
Iowa Gambling Lite21 studies, 8 as a primary outcome
- 25
Matrix Reasoning21 studies, 7 as a primary outcome
A test as a primary outcomeOnly in secondary or other outcomes
20% of depression and bipolar disorder studies name only instruments outside the library, such as clinician-administered screening scales. They count in every figure on this page and are not listed. The explorer below holds all 153 tests.
Tests used together
- Trail Making Test and Verbal Learning69 studies name both
- Digit Span Test and Trail Making Test67 studies name both
- Symbol Coding and Trail Making Test67 studies name both
- Stroop Color-Word Test and Trail Making Test57 studies name both
- Trail Making Test and Verbal Fluency57 studies name both
- Digit Span Test and Verbal Fluency56 studies name both
- Verbal Fluency and Verbal Learning56 studies name both
- Digit Span Test and Verbal Learning48 studies name both
- Symbol Coding and Verbal Learning44 studies name both
- Digit Span Test and Symbol Coding39 studies name both
Studies by start year
A test as a primary outcomeOnly in secondary or other outcomes
Show as a table
| Start year | Studies | A test as a primary outcome |
|---|---|---|
| 2000 | 1 | 1 |
| 2001 | 0 | 0 |
| 2002 | 2 | 1 |
| 2003 | 9 | 5 |
| 2004 | 4 | 3 |
| 2005 | 12 | 7 |
| 2006 | 7 | 1 |
| 2007 | 4 | 1 |
| 2008 | 11 | 5 |
| 2009 | 8 | 2 |
| 2010 | 20 | 6 |
| 2011 | 23 | 8 |
| 2012 | 23 | 9 |
| 2013 | 47 | 16 |
| 2014 | 39 | 12 |
| 2015 | 51 | 26 |
| 2016 | 60 | 22 |
| 2017 | 81 | 27 |
| 2018 | 64 | 15 |
| 2019 | 79 | 28 |
| 2020 | 72 | 28 |
| 2021 | 94 | 48 |
| 2022 | 89 | 26 |
| 2023 | 115 | 49 |
| 2024 | 106 | 36 |
| 2025 | 122 | 42 |
| 2026 | 94 | 35 |
Phases and sponsors
By phase
- Early phase 120 studies, 6 as a primary outcome
- Phase 138 studies, 14 as a primary outcome
- Phase 1/226 studies, 6 as a primary outcome
- Phase 2103 studies, 36 as a primary outcome
- Phase 2/314 studies, 2 as a primary outcome
- Phase 357 studies, 13 as a primary outcome
- Phase 482 studies, 33 as a primary outcome
- Not applicable740 studies, 259 as a primary outcome
- Observational167 studies, 95 as a primary outcome
Sponsors and study types
Lead sponsor: industry 69, NIH 6, universities, hospitals and others 1,172. Interventional 1,080, observational 167.
Status, results, interventions and countries
Status
- Recruiting244 studies, 94 as a primary outcome
- Not yet recruiting63 studies, 21 as a primary outcome
- Active, not recruiting41 studies, 19 as a primary outcome
- Completed607 studies, 241 as a primary outcome
- Stopped early92 studies, 30 as a primary outcome
- Status unknown200 studies, 59 as a primary outcome
What they test
- Behavioral352 studies, 126 as a primary outcome
- Drug353 studies, 124 as a primary outcome
- Device295 studies, 91 as a primary outcome
- Dietary supplement50 studies, 22 as a primary outcome
- Procedure38 studies, 10 as a primary outcome
- Diagnostic test18 studies, 10 as a primary outcome
- Biological15 studies, 7 as a primary outcome
- Radiation7 studies, 3 as a primary outcome
- Combination product9 studies, 1 as a primary outcome
- Genetic3 studies, 3 as a primary outcome
- Other232 studies, 91 as a primary outcome
- None given84 studies, 51 as a primary outcome
Intervention types as registered. A study can list several; observational studies often list none.
Where their sites are
- United States432 studies, 202 as a primary outcome
- China106 studies, 28 as a primary outcome
- Canada90 studies, 27 as a primary outcome
- France71 studies, 23 as a primary outcome
- United Kingdom62 studies, 14 as a primary outcome
- Germany55 studies, 23 as a primary outcome
- Spain39 studies, 13 as a primary outcome
- Taiwan35 studies, 11 as a primary outcome
- Denmark33 studies, 10 as a primary outcome
- Belgium25 studies, 6 as a primary outcome
- Netherlands25 studies, 5 as a primary outcome
- Brazil24 studies, 8 as a primary outcome
70 countries in all. A study with sites in several counts in each; 67 list no site.
Reported results
Completed studies with results posted on ClinicalTrials.gov, a results paper the registry links to the study, or both.
Completed depression and bipolar disorder studies: 311 of 607, 51%
Every completed study with a cognitive outcome: 3,626 of 7,953, 46%
| Results | Completed depression and bipolar disorder studies | Every completed study |
|---|---|---|
| Results on ClinicalTrials.gov and a paper | 87, 14% | 776, 10% |
| Results on ClinicalTrials.gov only | 81, 13% | 1,139, 14% |
| A results paper only | 143, 24% | 1,711, 22% |
| Neither | 296, 49% | 4,327, 54% |
How many participants they enroll
- Early phase 159 median, 23 to 118
- Phase 130 median, 16 to 86
- Phase 1/240 median, 23 to 60
- Phase 269 median, 40 to 105
- Phase 2/394 median, 60 to 120
- Phase 3111 median, 40 to 346
- Phase 460 median, 31 to 104
- Not applicable71 median, 42 to 130
- Observational140 median, 73 to 365
Show as a table
| Phase | Studies with a size | Median | Middle half |
|---|---|---|---|
| Early phase 1 | 19 | 59 | 23 to 118 |
| Phase 1 | 36 | 30 | 16 to 86 |
| Phase 1/2 | 26 | 40 | 23 to 60 |
| Phase 2 | 98 | 69 | 40 to 105 |
| Phase 2/3 | 13 | 94 | 60 to 120 |
| Phase 3 | 56 | 111 | 40 to 346 |
| Phase 4 | 81 | 60 | 31 to 104 |
| Not applicable | 730 | 71 | 42 to 130 |
| Observational | 163 | 140 | 73 to 365 |
When the cognitive outcome is measured
Latest time point of each outcome
- Within a day278 outcomes, 129 as a primary outcome
- Up to 4 weeks511 outcomes, 132 as a primary outcome
- 1 to 3 months864 outcomes, 301 as a primary outcome
- 3 to 6 months328 outcomes, 85 as a primary outcome
- 6 to 12 months141 outcomes, 35 as a primary outcome
- 1 to 2 years51 outcomes, 19 as a primary outcome
- Over 2 years56 outcomes, 26 as a primary outcome
- No duration given165 outcomes, 68 as a primary outcome
A test as a primary outcomeOnly in secondary or other outcomes
2,229 of the 2,394 outcome measures give a duration. A single visit counts as within a day.
Median time to the primary outcome, by test
| Test | Primary outcomes | Median |
|---|---|---|
| Verbal Learning | 47 | 11 weeks |
| Trail Making Test | 45 | 9 weeks |
| Digit Span Test | 41 | 8 weeks |
| Verbal Fluency | 37 | 8 weeks |
| Stroop Color-Word Test | 35 | 8 weeks |
| Symbol Coding | 33 | 8 weeks |
| Go/No-Go Task | 31 | 8 weeks |
| N-Back Task | 28 | 4 weeks |
| Continuous Performance Test | 25 | 8 weeks |
| Monetary Incentive Delay | 23 | 7 weeks |
Explore the depression and bipolar disorder studies
1,001 studies match. 388 name a library test in a primary outcome. Median size 73 participants. Median time to the primary outcome: 8 weeks.
Loading 1,001 studies; the filters turn on when they arrive.
2026 is partly planned starts. Not shown: 4 that started before 2000, 3 planned to start after 2026 and 1 with no start year.
Show as a table
| Start year | Studies | As a primary outcome |
|---|---|---|
| 2000 | 1 | 1 |
| 2001 | 0 | 0 |
| 2002 | 2 | 1 |
| 2003 | 7 | 5 |
| 2004 | 4 | 3 |
| 2005 | 10 | 5 |
| 2006 | 7 | 1 |
| 2007 | 4 | 1 |
| 2008 | 9 | 5 |
| 2009 | 7 | 2 |
| 2010 | 17 | 6 |
| 2011 | 20 | 8 |
| 2012 | 21 | 9 |
| 2013 | 37 | 12 |
| 2014 | 29 | 12 |
| 2015 | 43 | 23 |
| 2016 | 56 | 21 |
| 2017 | 67 | 26 |
| 2018 | 47 | 10 |
| 2019 | 63 | 23 |
| 2020 | 51 | 21 |
| 2021 | 81 | 42 |
| 2022 | 77 | 22 |
| 2023 | 93 | 38 |
| 2024 | 81 | 29 |
| 2025 | 86 | 31 |
| 2026 | 73 | 27 |
Library tests named most
Largest condition groups
Phases
Participants
Lead sponsor: industry 63, NIH 6, other 932. Interventional 884, observational 117.
As a primary outcomeSecondary or other outcome
The studies, newest registration first
Each number opens the study's record on ClinicalTrials.gov.
| Study | Start | Phase | Conditions | Participants | Lead sponsor | Status | Library tests named, with the latest time point |
|---|---|---|---|---|---|---|---|
| NCT07903896 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder, Sleep and sleep disorders, Anxiety, PTSD and OCD | Participants75 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07892326 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder | Participants200 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07892287 | Start2027 | PhaseNot applicable | ConditionsDepression and bipolar disorder | Participants20 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07881016 | Start2026 | PhaseNot applicable | ConditionsSchizophrenia and psychosis, Depression and bipolar disorder, Autism | Participants3,000 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07879924 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder | Participants60 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07873060 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder | Participants80 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07871916 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder, Anxiety, PTSD and OCD | Participants96 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07866794 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder, Anxiety, PTSD and OCD | Participants135 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07857291 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder | Participants320 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07857122 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder | Participants108 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07848477 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder | Participants60 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07845409 | Start2027 | PhaseNot applicable | ConditionsDepression and bipolar disorder | Participants138 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07834203 | Start2025 | PhaseObservational | ConditionsSchizophrenia and psychosis, Depression and bipolar disorder | Participants500 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07829510 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder, Substance use and addiction, Anxiety, PTSD and OCD | Participants300 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07823218 | Start2026 | PhaseObservational | ConditionsDepression and bipolar disorder | Participants100 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07813169 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder | Participants60 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07780695 | Start2023 | PhaseNot applicable | ConditionsDepression and bipolar disorder | Participants45 | Lead sponsorOther | StatusCompleted | Library tests named
|
| NCT07765355 | Start2025 | PhaseNot applicable | ConditionsDepression and bipolar disorder, Anxiety, PTSD and OCD | Participants60 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07757997 | Start2026 | PhaseObservational | ConditionsDepression and bipolar disorder | Participants143 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07755839 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder, Cancer, Anxiety, PTSD and OCD | Participants60 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07750925 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder, Healthy volunteers, Anxiety, PTSD and OCD | Participants45 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07735910 | Start2026 | PhaseNot applicable | ConditionsMild cognitive impairment, Depression and bipolar disorder, Sleep and sleep disorders, Anxiety, PTSD and OCD | Participants60 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07717866 | Start2022 | PhaseObservational | ConditionsBrain injury and concussion, Depression and bipolar disorder, Anxiety, PTSD and OCD | Participants52 | Lead sponsorIndustry | StatusActive, not recruiting | Library tests named
|
| NCT07710222 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder | Participants60 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07690709 | Start2023 | PhaseNot applicable | ConditionsDepression and bipolar disorder, Anxiety, PTSD and OCD | Participants78 | Lead sponsorOther | StatusCompleted | Library tests named
|
Questions, answered from the data
Which cognitive test do depression and bipolar disorder trials use most?
The Trail Making Test: 204 of the 1,247 registered studies name it in an outcome measure, 16%. Next come Verbal Learning (178) and Verbal Fluency (154).
Which cognitive test do depression and bipolar disorder trials use most as a primary outcome?
The Trail Making Test, named in a primary outcome by 52 studies. 464 of the 1,247 studies, 37%, name a cognitive test in a primary outcome.
How many participants does a phase 2 depression and bipolar disorder trial enroll?
Half of the phase 2 depression and bipolar disorder studies enroll 69 participants or fewer, and the middle half enroll 40 to 105. 98 of them give a size.
How long after the start do depression and bipolar disorder trials measure a cognitive outcome?
Half of the primary outcomes that name a library test are measured within 8 weeks of the start, and the middle half from 2 weeks to 13 weeks. 727 primary outcomes give a duration.
Which cognitive tests do depression and bipolar disorder trials use together?
The Trail Making Test with Verbal Learning most often: 69 studies name both. Next, the Digit Span Test with the Trail Making Test (67).
How many completed depression and bipolar disorder trials have reported results?
311 of the 607 completed depression and bipolar disorder studies, 51%, have reported results: 168 posted them on ClinicalTrials.gov, 230 have a results paper linked to the registry record, and 87 did both. The other 296 show neither. Of all completed studies with a cognitive outcome, 46% have reported results.
How the studies are counted
For each test family, the census runs ClinicalTrials.gov's own outcome search for the family's names and reads every study first posted by the day the family was counted. These studies were read on 10 November 2026. A study counts once on a page, however many tests it names. Counts for a test cover every version of the task under any of its names, so a page can count studies that used a commercial version.
The census adds two things to each record and changes nothing in it: which outcome list names the test (primary, then secondary, then other), and the condition groups, matched on the study's condition names and MeSH terms. A study can fall in several groups; one whose only condition is cognitive impairment or decline falls in “Cognitive impairment and decline”. Studies that name only instruments outside the library count in every total and share but are not listed.
A second read on 10 November 2026 added each study's overall status, whether results are posted, its intervention types, the countries of its sites and the time frame of the outcome that names each test. A time frame counts by the latest time point it names: “Baseline, 12 and 24 weeks” is 24 weeks, a single visit is within a day, and one that names no duration, such as “end of treatment”, is left out of the timings.
A third read on 10 November 2026 added the papers the registry links to each study: those its sponsor lists as reporting results, and those PubMed links to it through the study's NCT number. A study has a results paper when one of them came out in or after the month of its primary completion and PubMed does not class it as a protocol, review or comment. A paper that never gives the NCT number is not linked, so some studies counted as reporting neither did publish.
Source: ClinicalTrials.gov, a database of the U.S. National Library of Medicine, which does not endorse these pages. Every study line is in the data release 2.1.0, and the explorer's own file is clinical-trials-studies.json.
Plan the cognitive outcomes of a depression and bipolar disorder trial
Choose tests with a record in registered trials, and run them in a browser at every site, on the same version each visit.