The purpose of the study is to investigate if NS2359 is effective in the treatment of ADHD in adult patients.

Inclusion Criteria:

• Patients with the diagnosis of Attention Deficit Hyperactivity Disorder (ADHD), by DSM-IV, as manifested in clinical evaluation and confirmed by structured interview using the K-SADS-E adult ADHD module
• Patients with a CGI Global Severity (GS) score ≥4 (moderate impairment)
• The Patient provided written informed consent.
• Non-lactating women of childbearing potential that used adequate contraception (i.e. the use of oral contraceptives and practising a double-barrier form of birth control) and had a negative pregnancy test at screening. Women of no childbearing potential who had been postmenopausal for less than 2 years must have a negative pregnancy test at screening.

Exclusion Criteria:

• Any clinically unstable medical condition
• Clinically significant abnormal baseline laboratory values
• Mental retardation
• Organic brain disorders
• Non-febrile seizure disorder
• Patients with a history of an eating disorder including anorexia or bulimia nervosa
• Psychotic disorder of any type
• Patients with a HAM-D (17 item) >15
• Patients currently (within the past 6 months) known to abuse or to be dependent on any drug, including alcohol or a positive urine drug screen for cocaine, heroin, or marijuana
• Treatment with stimulants was prohibited within 1 week prior to randomisation
• Treatment with antipsychotics/neuroleptics was prohibited for 8 weeks prior to randomisation
• Treatment with monoamine oxidase inhibitors was prohibited for 8 weeks prior to randomisation
• Treatment with tricyclic antidepressants, histamines and selective serotonin reuptake inhibitors was prohibited for 4 weeks (fluoxetine for 6 weeks) prior to randomisation
• Treatment with benzodiazepines, anticonvulsants (for behaviour) and lithium for 2 weeks prior to randomisation
• Patients with a history of bipolar disorder
• Patients using any concurrent medication for the treatment of ADHD
• Patients that had previously participated in a NS2359 study
• Patients treated with an investigational drug within 30 days or 5 half-lives (whichever is longer) preceding the first dose of study medication
• Patients with a history of positive human immunodeficiency virus (HIV) test.