This phase Ib study aims to evaluate applicability of touchscreen-based cognitive test battery for assessment of ketamine-induced schizophrenia-like cognitive deficits in healthy volunteers. Additionally, the study aims to assess whether ketamine-induced cognitive deficits are reversed by modafinil using touchscreen-based test battery for testing of cognition.

Ketamine-induced schizophrenia-like cognitive deficits in healthy volunteers are measured by using touchscreen-based cognitive tests. In addition, the study aims to assess whether ketamine-induced cognitive deficits detected by touchscreen-based cognitive tests are reversed by modafinil.

Inclusion Criteria:

• Healthy Caucasian men aged 20-40 years
• Body weight 50-100 kg
• Body mass index 19-26 kg/cm2
• Normal physical examination including heart rate (HR; 50-90/min) blood pressure (BP; diastolic 65-90 and systolic 110-140) normal haematological and clinical chemistry variables normal ECG as judged by the investigator

Exclusion Criteria:

• Visual disability or red-green color blindness
• History of mental health disorders as determined by self-reported a) physician-determined diagnoses of mental health disorders, except for nicotine and caffeine dependence, or history of suicide attempt; b) medications for mental health disorders
• History of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, or neurological disorder
• History of orthostatic syncope
• History of head injury with sequelae
• First-degree relative with a history of psychosis or epilepsy/seizure disorder or of a condition with risk of seizures
• Current regular medication
• Vaccination 2 weeks prior to study or during the study
• Known or suspected allergy/hypersensitivity to any drug
• History of regular alcohol consumption
• Current substance dependence (excluding nicotine and caffeine).
• Use of tobacco- or nicotine-containing products in excess of the equivalent of 5 cigarettes per day
• Use of any medication or alcohol 24 hours before each study visit
• Education less than high school
• Clinically relevant symptoms of depression, anxiety or sleep disturbances
• Donation of blood within 1 month prior to study
• Participation in any study with an investigational product within 2 months prior to study
• Clinical signs of suicidal or violent behaviour or psychotic symptoms

Double blinded