A Study of Memantine Hydrochloride (Namenda®) for Cognitive and Behavioral Impairment in Adults With Autism Spectrum Disorders

Inclusions

- Male and female outpatients 18-50 years of age.

- Participants must have DSM-IV-TR diagnosis of PDD and displaying PDD symptoms with at
least moderate impairment (SRS score ≥ 85 and CGI-PDD ≥ 4).

- Fulfills diagnosis of autism spectrum disorders by meeting DSM-IV-TR PDD diagnostic
criteria of autistic disorder (with the exception of a total lack of spoken
language), Asperger's disorder, or PDD-NOS as established by clinical interview and
confirmed by DICA-R PDD module.

- Subjects and/or their legal representative must have a level of understanding
sufficient to communicate intelligently with the investigator and study coordinator,
and to cooperate with all tests and examinations required by the protocol.

- Subjects and/or their legal representative must be considered reliable reporters.

- Each subject and/or their authorized legal representative must understand the nature
of the study. The subject and/or their legal representative must sign an informed
consent document.

- Subject must be able to participate in mandatory blood draws.

- Subject must be able to swallow pills.

- Subjects with mood, anxiety, or disruptive behavior disorders will be allowed to
participate in the study provided they do not meet any exclusionary criteria.

Exclusions

- IQ < 85.

- Total lack of spoken language.

- DSM-IV-TR PDD diagnoses of Rett's disorder, or childhood disintegrative disorder.

- Clinically unstable psychiatric conditions or judged to be at serious suicidal risk.

- Active symptoms of anorexia or bulimia nervosa

- Current diagnosis of a psychotic disorder or unstable bipolar disorder.

- History of recent or current (past 30 days) clinically significant depressive or
anxiety disorder that warrants treatment.

- Current diagnosis of schizophrenia.

- History of substance use (except nicotine or caffeine) within past 3 months

- Serious, stable or unstable systemic illness including hepatic, renal,
gastroenterological, respiratory, cardiovascular (including ischemic heart disease),
endocrinologic, neurologic, immunologic, or hematologic disease.

- Subjects with severe hepatic impairment (LFTs > 3 times ULN) and those with severely
impaired renal function (eGFR < 30).

- Subjects with genitourinary conditions that raise urine pH (e.g., renal tubular
acidosis, severe infection of the urinary tract).

- Uncorrected hypothyroidism or hyperthyroidism.

- Subjects with untreated and/or unstable diabetes.

- Non-febrile seizures without a clear and resolved etiology.

- Pregnant or nursing females.

- Known hypersensitivity to memantine.

- Severe allergies or multiple adverse drug reactions.

- A non-responder or history of intolerance to memantine, after treatment at adequate
doses as determined by the clinician.

- Investigator and his/her immediate family defined as the investigator's spouse,
parent, child, grandparent, or grandchild.