SPD503 in Subjects Aged 6-17 Years With Generalized Anxiety Disorder (GAD), Separation Anxiety Disorder (SAD), or Social Phobia (SoP)

Inclusion Criteria:

1. Outpatient subjects aged 6-17 years inclusive at the time of consent/assent
(Screening Visit [Visit 1] only).

2. Subject's parent or legally authorized representative (LAR) must provide signature of
informed consent, and there must be documentation of assent by the subject indicating
that the subject is aware of the investigational nature of the study and the required
procedures in accordance with the International Conference on Harmonisation (ICH)
Good Clinical Practice (GCP) Guidance E6 (1996) and applicable regulations before
completing any study-related procedures (Screening Visit [Visit 1] only).

3. Subject meets Diagnostic and Statistical Manual of Mental Disorders Fourth Edition,
Text Revision (DSM-IV-TR) criteria for a Primary Diagnosis of 1 or any combination of
the following; GAD, SAD or SoP (300.02, 309.21 and 300.23), based on a detailed
psychiatric evaluation at screening including completion of the Anxiety Disorders
Interview Schedule for DSM-IV Child Version (ADIS-C).

4. Subject has a score of >/= 4 on the Clinician Severity Rating Scale for the Principal
Diagnosis on the ADIS-C CSR) at the Screening Visit (Visit 1) and the Baseline Visit
(Visit 2).

5. Subject is functioning at an age-appropriate level intellectually, as determined by
the Investigator.

6. Subject and parent/LAR understand, are able, willing, and likely to fully comply with
the study procedures and restrictions defined in this protocol, in the opinion of the
Investigator.

7. Subject is able to swallow intact tablets.

8. Subjects who are females of child-bearing potential (FOCP), defined as >/= 9 years of
age or if <9 years of age are post-menarchal, must have a negative serum beta Human
Chorionic Gonadotropin (HCG) pregnancy test at the Screening Visit (Visit 1) and a
negative urine pregnancy test at the Baseline Visit (Visit 2) and Week 12 (Visit
11/ET). Females of child-bearing potential must abstain from sexual activity that
could result in pregnancy or agree to use acceptable methods of contraception.

Exclusion Criteria:

1. Subject has a current co-morbid psychiatric diagnosis of a major depressive disorder,
bipolar illness, psychosis, a pervasive development disorder other than Asperger's
Syndrome, attention deficit hyperactivity disorder, an eating disorder, or substance
abuse disorder.

2. Subject has an ADIS-C CSR score for any Axis I disorder that is greater than the
ADIS-C CSR score for their Principal Diagnosis of GAD, SAD, or SoP.

3. Subject has any condition or illness which, in the opinion of the Investigator,
represents an inappropriate risk to the subject and/or could confound the
interpretation of the study.

4. Within 14 days prior to the Baseline Visit subject has received any evidence-based
psychosocial intervention intended to reduce anxiety symptoms i.e. Individual
Cognitive Behavioral Therapy, Group Cognitive Behavioral Therapy, or Social
Effectiveness Training.

5. Subject has started or changed the type or intensity of a non evidence-based
psychosocial intervention intended to reduce anxiety symptoms within 6 weeks prior to
the Baseline Visit (Visit 2).

6. Subject has a known history or presence of structural cardiac abnormalities, serious
heart rhythm abnormalities, syncope, cardiac conduction problems (e.g., clinically
significant heart block), exercise-related cardiac events including syncope and pre
syncope, or clinically significant bradycardia.

7. Subject with orthostatic hypotension or a known history of controlled or uncontrolled
hypertension.

8. Subject has a blood pressure measurement above the 95th percentile for age, sex, and
height.

9. Subject has a history of a seizure disorder other than a single childhood febrile
seizure occurring before the age of 3 years.

10. Subject is currently considered at risk for suicide in the opinion of the
Investigator, has previously made a suicide attempt, or is currently demonstrating
active suicidal ideation. Subjects with intermittent passive suicidal ideation are
not necessarily excluded based on the assessment of the Investigator.

11. Subject is unable to limit caffeine intake to 2 servings per day throughout
participation in the study beginning at time of informed consent/assent.

12. Subject has a history of alcohol or other substance abuse or dependence, as defined
by DSM-IV within the last 6 months.

13. Clinically important abnormality on drug and alcohol screen at the Screening Visit
(Visit 1) or Baseline Visit (Visit 2).

14. History of failure to respond to 2 adequate trials (consisting of an appropriate dose
and adequate duration of therapy) of an SSRI or one trial of cognitive behavioral
therapy for the treatment of GAD, SAD, or SoP.

15. Subject is well controlled on anxiolytic pharmacologic or non-pharmacologic therapy
with acceptable tolerability.

16. Subject is currently using a prohibited medication or other medications, including
herbal supplements that have identified anxiolytic or anxiogenic effects, that affect
BP or heart rate or that have CNS effects in violation of the protocol-specified
washout criteria at the Baseline Visit (Visit 2).

17. Subject is currently using valproic acid or any drug known to inhibit or induce
CYP3A4/5 in violation of the protocol-specified washout criteria at the Baseline
Visit (Visit 2).

18. Use of another investigational medicinal product or participation in a clinical study
within 30 days prior to the Baseline Visit (Visit 2).

19. Subject is significantly overweight based on Center for Disease Control and
Prevention body mass index (BMI)-for-age sex specific charts at the Screening Visit
(Visit 1). Significantly overweight is defined as a BMI >95th percentile for this
study.

20. Subject has a known or suspected allergy, hypersensitivity, or clinically significant
intolerance to guanfacine hydrochloride or any components found in SPD503.

21. Subject is female and is pregnant or currently lactating.

22. Subject failed screening or was previously enrolled in this study.

23. Subject has another member of the same household currently participating in this
study.