Inclusion Criteria:
- Diagnosed with SCD
- Enrolled on the institutional protocol: Sickle Cell Clinical Research Intervention Program (SCCRIP)
- Between the ages of 8.0 and 17.9 years
\*Included if performance measure, rating scale or diagnostic criteria met (within the past 2 years):
- \*Score at or below a Standard Score of 85 (16th percentile) on any 2 out of 4 performance measures:
- NIH Toolbox Flanker
- NIH Toolbox List Sorting
- NIH Toolbox Dimensional Change Card Sort Test (DCST)
- Wechsler Intelligence Scale for Children (WISC) -5/ Wechsler Adult Intelligence Scale (WAIS)-4 Digit Span Forward (DSF)
- \*Score at or above a T Score of 60 (84th percentile) on any 1 out of 2 parent rating scales:
- BRIEF-2 Global Executive
- BASC-3 Attention
- \*Have a documented diagnosis of attention deficit / hyperactivity disorder (any subtype)
- English as the primary language
- Research participant and one caregiver willing to participate and provide consent/assent according to institutional guidelines
- Negative pregnancy test in female participant of childbearing age
Exclusion Criteria:
- Primary language other than English
- Score below the 2nd percentile on the Wechsler Abbreviated Scale of Intelligence (WASI)-2 intelligence quotient (IQ) test (ever)
- Uncontrolled seizures (seizure within the past 6 months)
- Cardiomyopathy or known congenital structural cardiac defects
- Stenotic valvular disease, left coronary artery stenosis, or history of myocarditis or pericarditis
- History of heart arrhythmia including ventricular tachycardia, ventricular fibrillation, supraventricular tachycardia, QT prolongation or concomitant use of medications associated with QT prolongation
- Two or more prior episodes of priapism
- Blood pressure >95th percentile at the three most recent visits consecutively (i.e., >95th percentile reading at all three of the most recent hospital visits to St. Jude).
- If blood pressure is > 95th %ile compared to age-norms on the day of the baseline visit, a repeat blood-pressure reading will be performed both electronically and manually to confirm findings.
- Stimulant medication within the past two weeks
- Severe sensory loss
- Previous adverse reaction to methylphenidate
- Inability or unwillingness of research participant or legal guardian/representative to give written informed consent.
- Currently prescribed another investigational medication.
- Diagnosed with sickle cell-hereditary persistence of fetal hemoglobin (HbSHPFH), sickle cell homozygous C (CC), Hb S/N-Baltimore, or other rare genotypes that would preclude the participant from having the classic symptoms of sickle cell disease
- Currently prescribed any of the following:
- Phenobarbital (anticonvulsant)
- Phenytoin (anticonvulsant)
- Primidone (anticonvulsant)
- Warfarin (anticoagulant)
- Antipsychotic medications
- Selective Serotonin Reuptake Inhibitor (SSRI) medications
- Tricyclic antidepressant (TCA) medications
- Vasopressor medications