A Study of TD-9855 in Adults With Attention-Deficit/Hyperactivity Disorder (ADHD)

Inclusion Criteria:

- Subjects must meet the following ADHD diagnostic and inclusion criteria:

- Subjects must meet Diagnostic and Statistical Manual of Mental Disorders, Fourth
Edition, Text Revision (DSM-IV-TR) criteria for current ADHD subtypes (ADHD combined
type, ADHD predominately inattentive type, ADHD predominately hyperactive-impulsive
type) as assessed by the clinical interview and confirmed by Adult
Attention-Deficit/Hyperactivity Disorder Clinical Diagnostic Scale (ACDS V1.2).

- Subjects must have a total score of 24 or greater on the AISRS at both the Screening
and Baseline Visits AND the Baseline Visit AISRS scores must not vary by more than 20%
from Screening.

- Subjects are required to have CGI-S score ≥4 (moderate) at both the Screening and
Baseline Visits. Subjects should have at least moderate severity for ADHD symptoms.

- For women of childbearing potential, documentation of a negative serum pregnancy test
at Screening and a negative urine pregnancy test on Day 0. All female subjects of
childbearing potential must be using a highly effective method of birth control during
the study and for at least 1 month after completion of study drug dosing.

- A highly effective method of birth control is defined as one that results in a low
failure rate (i.e., <1% per year) when used consistently and correctly, such as condom
+ diaphragm, condom + spermicide, diaphragm + spermicide, or intrauterine device [IUD]
with documented failure rate of <1% per year, or oral/injectable/implanted hormonal
contraceptives used in combination with a barrier method.

- Women are considered to be not of childbearing potential if they have had a total
hysterectomy or bilateral tubal ligation (documentation for either must be provided
before enrollment) or are at least 2 years postmenopausal. Female subjects cannot be
breast-feeding.

Exclusion Criteria:

Any current psychiatric disorder other than ADHD as defined in DSM-IV-TR as assessed by
Mini International Neuropsychiatric Interview (MINI). Subjects with dysthymia that does not
require pharmacological treatment will not be excluded.

- MADRS total score >15.

- A diagnosis of ADHD NOS.

- Any diagnosis of lifetime bipolar disorder or psychotic disorder

- A current diagnosis of any severe comorbid Axis II disorder

- Any history of mental retardation, organic mental disorders due to general medical
condition or pervasive developmental disorder as defined by DSM-IV-TR.-