Please select the eligibility criteria that correspond to the clinical trial below.
Title: An Open-Label Extension Study of the Safety and Tolerability of Memantine in Pediatric Patients With Autism, Asperger's Disorder, or Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS)
Brief Summary: The objective of this study is to evaluate the long-term safety and tolerability of memantine in the treatment of pediatric patients with autism, Asperger's Disorder or Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS).


Options:
A: Inclusion criteria

* Participant is currently in treatment in the Johns Hopkins Bayview Medical Center (JHBMC)
* Participant has a diagnosis of:

  * Autistic Disorder
  * Asperger's Disorder
  * Pervasive Developmental Disorder (PDD) NOS
* Participant meets one of the following criteria:

  * CGI-S \>= 4 (CGI-S: ________)
  * Participant has the following problematic behaviors (at least one) that might be expected to benefit from memantine:

    1. _____________________________________________
    2. _____________________________________________
    3. _____________________________________________

Exclusion criteria

The patient meets none of the following criteria (mark if absent):

* Active seizures (Patients with a history of seizures, who have been seizure-free on an antiepileptic regimen for six months or more would be eligible).
* Rett's Syndrome or Childhood Disintegrative Disorder
* Active treatment with an acetylcholinesterase inhibitor
* Prior or current treatment with memantine
* Current treatment with lamotrigine
* Genetic, metabolic or degenerative disorder (excepting Fragile X).
* Brain malformation or known severe brain trauma
* Pregnancy or breastfeeding
* Glomerular Filtration Rate (GFR) \< 30 mL/min
B: Inclusion Criteria

1. Male or female outpatients 6 to 12 years of age
2. Verbal; Module 2 or 3 on Autism Diagnostic Observation Schedule (ADOS)
3. Meet Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) for Autism Spectrum Disorder. The diagnosis will be confirmed with Autism Diagnostic Interview-Revised (ADI-R) and ADOS Module 2 or 3.
4. Parents report difficulties with motor skills
5. Have a Clinician's Global Impression-Severity (CGI-S) score ≥ 4 (moderately ill) at Screening and Baseline
6. If already receiving stable nonpharmacologic educational, behavioral, and/or dietary interventions, have continuous participation during the preceding 3 months prior to Screening and will not electively initiate new or modify ongoing interventions for the duration of the study
7. Participants can be on up to 2 concomitant psychotropic medications before entering the study, provided that they have been on a stable dose for 30 days and have no plans to adjust the dose for the duration of study
8. Have normal physical examination and laboratory test results at Screening. If abnormal, the finding(s) must be deemed clinically insignificant by the Investigators
9. Prior to the conduct of any study-specific procedures, the patient must provide assent to participate in the study (if developmentally appropriate), and the parent or legal guardian must provide written informed consent
10. The patient and the patient's parent or legal guardian must be able to speak and understand English sufficiently to understand the nature of the study and to allow for the completion of all study assessments
11. The parent or legal guardian must be capable of providing reliable information about the patient's condition, agree to oversee the administration of study drug, and accompany the patient to all clinic visits

Exclusion Criteria:

1. Patients born prior to 35 weeks gestational age
2. Patients with any primary psychiatric diagnosis other than autism at Screening: a history of Attention Deficit Hyperactivity Disorder (ADHD), bipolar disorder, psychosis, post-traumatic stress disorder, schizophrenia, or major depressive disorder
3. Patients with a medical history of neurological disease, including, but not limited to, epilepsy/seizure disorder (except simple febrile seizures), movement disorder, tuberous sclerosis, fragile X, and any other known genetic syndromes, or known abnormal MRI/structural lesion of the brain
4. Patients with a medical condition that might interfere with the conduct of the study, confound interpretation of the study results, or endanger their own well-being. Patients with evidence or history of malignancy or any significant hematological, endocrine, cardiovascular (including any rhythm disorder), respiratory, renal, hepatic, or gastrointestinal disease.
5. Patients who plan to initiate or change pharmacological or nonpharmacologic interventions during the course of the study
6. Patients on d-cycloserine or riluzole as they both target the glutamate system
7. Patients on agents that alkalinize the urine (acetazolamide, potassium citrate, and sodium bicarbonate), as they decrease the elimination of memantine
8. Patients who have received treatment with memantine in the past with no response
9. Patients with a history of hypersensitivity reaction to dextromethorphan, amantadine, or any other NMDA receptor antagonists
10. Patients unable to tolerate venipuncture procedures for blood sampling
11. Patients who, in the Investigator's opinion, might not be suitable for the study
12. Children weighing under 20 kg (to meet FDA approvals)
13. Patients with a positive pregnancy test
C: INCLUSION CRITERIA

All Participants:

1. Male and female participants, ages 8-17 years (inclusive)

   Participants with Autism Spectrum Disorder:
2. Meets Diagnostic and Statistical Manual-5 autism spectrum disorder diagnostic criteria, as established by clinical diagnostic interview
3. At least moderate severity of social impairment, as measured by a total raw score of ≥85 on the parent/guardian-completed Social Responsiveness Scale, Second Edition (SRS-2) and a score of ≥4 on the clinician-administered Autism Spectrum Disorder Clinical Global Impression-Severity scale (ASD CGI-S)

Healthy Control Participants:

2. Age-, sex-, and IQ-matched with participants with autism spectrum disorder 3. No Axis I diagnoses, as established by the Kiddie Schedule for Affective Disorders and Schizophrenia-Epidemiological Version (K-SADS-E) and confirmed by clinical diagnostic interview 4. No significant traits of autism spectrum disorder, as measured by a total raw score of \<60 on the parent/guardian-completed Social Responsiveness Scale, Second Edition

EXCLUSION CRITERIA

All Participants:

1. IQ ≤70 based, on the Wechsler Abbreviated Scale of Intelligence, Second Edition (WASI-II) Vocabulary and Matrix Reasoning subtests
2. Impaired communicative speech
3. Current treatment with the following medications, which are known to impact glutamate levels:

   1. Lamotrigine
   2. Amantadine
   3. N-acetylcysteine
   4. D-cycloserine
4. Current treatment with a psychotropic medication, not listed above, on a dose that has not been stable for at least 4 weeks prior to study baseline
5. Co-administration of drugs that compete with memantine for renal elimination using the same renal cationic system, including hydrochlorothiazide, triamterene, metformin, cimetidine, ranitidine, quinidine, and nicotine
6. Initiation of a new psychosocial intervention within 30 days prior to randomization
7. Participants who are pregnant and/or nursing
8. Participants with a history of non-febrile seizures without a clear and resolved etiology
9. Participants with a history of or a current liver or kidney disease
10. Clinically unstable psychiatric conditions or judged to be at serious suicidal risk
11. Participants who meet for alcohol or drug dependence or abuse on the Kiddie Schedule for Affective Disorders and Schizophrenia-Epidemiological Version. If the participant has a recent history of substance abuse, as an added precaution, there will be a 2-week washout period before initiating the trial. There are no known safety issues relating to memantine and recent history of substance abuse.
12. Serious, stable or unstable, systemic illness, including hepatic, renal, gastroenterological, respiratory, cardiovascular (including ischemic heart disease), endocrinologic, neurologic, immunologic, or hematologic disease
13. Participants with severe hepatic impairment (Liver Function Tests \[LFTs\] \>3 times the Upper Limit of Normal \[ULN\])
14. Participants with genitourinary conditions that raise urine Power of Hydrogen (pH) (e.g., renal tubular acidosis, severe infection of the urinary tract)
15. Known hypersensitivity to memantine
16. Severe allergies or multiple adverse drug reactions
17. A non-responder or history of intolerance to memantine after treatment at adequate doses, as determined by the clinician
18. Investigator and his/her immediate family, defined as the Investigator's spouse, parent, child, grandparent, or grandchild.
D: Inclusion Criteria:

* Patients who completed Study MEM-MD-67, MEM-MD-68, MEM-MD-91, or discontinued Study MEM-MD-68 due to meeting the criterion for loss of therapeutic response.
* Having normal results from a physical examination and laboratory tests at Visit 1 of this study (last visit of the preceding study). Any abnormal findings must be deemed not clinically significant by the Investigator and documented as such.
* Have a family that is sufficiently organized and stable to guarantee adequate safety monitoring and continuous attendance to clinic visits for the duration of the study

Exclusion Criteria:

* Patients who discontinued a preceding memantine study due to an adverse event possibly related to study drug
* Patients with a concurrent medical condition that might interfere with the conduct of the study, confound interpretation of the study results, or endanger the patient's well being
* Significant risk of suicidality based on the Investigator's judgment, Aberrant Behavior Checklist-irritability subscale (ABC-I), or if appropriate, as indicated by a response of "yes" to questions 4 or 5 in the suicidal ideation section of the Children's Columbia-Suicide Severity Rating Scale (C-SSRS) or any suicidal behavior

Answer: D