Evaluation of the Efficacy and Safety of EB-1020 in Adult ADHD Patients

Inclusion Criteria:

• Participants diagnosed primarily with ADHD (excluding other specified or unspecifiedattention-deficit/hyperactivity disorder) according to DSM-5 criteria, based oninformation collected through interviews using the Japanese version of the Conners'Adult ADHD Diagnostic Interview for DSM-IVTM (CAADID).

• Participants with an AISRS total score meeting the following criteria:

• Not receiving medication treatment for ADHD: 28 points or higher

• Receiving medication treatment for ADHD: 22 points or higher

Exclusion Criteria:

• Participants who are pregnant or breastfeeding, and those who test positive forpregnancy at screening.

• Participants have a current comorbid psychiatric disorder that either could beexpected to require treatment with medications prohibited in this trial, or toconfound efficacy or safety assessments. Examples include, but are not limited to,psychotic disorder (current or lifetime), bipolar disorder (current or lifetime),generalized anxiety disorder, obsessive-compulsive disorder, panic disorder, acurrent major depressive episode, or posttraumatic stress disorder, as establishedby the MINI.

• Participants diagnosed with a personality disorder according to DSM-5 criteria.

• Participants diagnosed with autism spectrum disorder according to DSM-5 criteria.

• Participants diagnosed with intellectual disability and an IQ score below 70.

• Participants who, in the judgment of the principal or sub-investigator, or based onthe following criteria, are at significant risk of suicide:

• Clear suicidal ideation or a history of suicidal behavior (within the past 6months) as indicated by a ""yes"" answer to questions 4 or 5 in the suicidalideation section of the C-SSRS Baseline/Screening version at screening.

• Participants who have a current or past episode of substance-related disorders (excluding tobacco-related disorders) according to DSM-5 diagnostic criteria.

• Participants diagnosed with eating disorders and feeding disorders according toDSM-5 diagnostic criteria.

• Participants who show a positive reaction in alcohol tests or urine drug tests atscreening.

• Participants with complications or a history of the following neurologicaldisorders:

• Epilepsy

• Seizures (other than infantile febrile seizures)

• Syncope

• Tourette's disorder

• History of significant head trauma with clinically significant loss ofconsciousness

• Dementia

• Cerebrovascular disease

• Parkinson's disease

• Intracranial lesions

• Other severe neurological disorders

• Participants with complications or a history of cardiovascular diseases.

• Participants with clinical laboratory test results at screening that meet any of thefollowing criteria:

• Platelets <= 75,000/mm3

• Hemoglobin <= 9 g/dL

• Neutrophils, absolute <= 1000/mm3

• AST > 2 x ULN

• ALT > 2 x ULN

• Creatinine >= 2 mg/dL

• CPK >= 2 x ULN (except for the cases that the medical monitor determined thatparticipant's inclusion is possible based on the discussion about theparticipant's condition with the investigator or subinvestigator) •Abnormalvalues for both free T4 and TSH•

• Participants who cannot agree to discontinuation of prohibited concomitantmedication, such as ADHD medication or antidepressants.