This single-center, randomized, double-blind, two-period crossover study will evaluate the safety, tolerability, pharmacokinetics and pharmacodynamic effects of the combination of multiple doses of RO5285119 with a single dose of risperidone in healthy volunteers. Subjects will be randomized to one of 4 treatment sequences of two periods to receive multiple doses of RO5285119 plus a single dose of risperidone or risperidone placebo or multiple doses of RO5285119 placebo plus a single dose of risperidone or risperidone placebo, with a washout period of approximately 3 weeks between treatment periods. Anticipated time on study is up to 12 weeks (from screening through study completion).

Inclusion Criteria:

• Healthy male and female adults, 18 - 50 years of age inclusive Healthy status is defined by absence of evidence of any active or chronic disease following detailed medical and surgical history and a physical examination including vital signs, 12-lead ECG, hematology, blood chemistry, serology and urinalysis
• Body mass index (BMI) 18 to 30 kg/m2 inclusive
• Women have to be postmenopausal or surgically sterile
• Male subjects must use a barrier method of contraception for the duration of the study and for 3 months after last dosing

Exclusion Criteria:

• Suspicion of regular consumption of drug of abuse, or history of drug or alcohol abuse

• Positive for hepatitis B, hepatitis C or HIV infection

• History of clinically significant hypersensitivity or allergic reactions

• Disorders of the central nervous system, including psychiatric disorders, behavioural disturbances, cerebrovascular events, depression, bipolar disorder, migraine, Parkinson

• Regular smoker (>5 cigarettes, >3 pipe-fulls, >3 cigars per day)

• Administration of an investigational drug or device within 3 months prior to first dosing

  • Hypersensitivity to risperidone or any of its excipients

• Any other known contraindications to risperidone as stated in the SmPC