Adjuvant Treatment With a Glycine Uptake Inhibitor in Participants With Negative Symptoms of Schizophrenia (P05695) (MK-8435-001)

Exclusion Criteria

• •Has an overall PANSS positive subscale score ≥20
• •Has a score ≥5 on 2 or more of the following PANSS positive subscale items at study start: delusions, hallucinatory behavior, excitement, grandiosity, or suspiciousness/persecution
• •Has a score ≥9 on the modified InterSePT Scale for Suicidal Thinking
• •Has a score ≥9 on the Calgary Depression Scale for Schizophrenia
• •Has a score ≥3 on the clinical global impression of Parkinsonism of the abbreviated Extrapyramidal Symptom Rating Scale
• •Has untreated or uncompensated clinically significant renal, endocrine, hepatic, respiratory, cardiovascular, hematological, immunological or cerebrovascular disease, malignancy, or other chronic and/or degenerative process
• •Has a history of seizure disorder beyond childhood or is taking any anticonvulsants to prevent seizures
• •Has a diagnosis of mental retardation or organic brain syndrome
• •Has a clinically relevant visual disturbance, such as cataract, color blindness, macular degeneration, glaucoma, or retinal disease
• •Has a concurrent diagnosis of substance dependence other than nicotine or caffeine dependence in the past 6 months prior to study start
• •Has a positive result on the urine alcohol/drug screen for alcohol or illicit drugs
• •Is pregnant or breastfeeding
• •Is being treated with high doses of benzodiazepines (\>4 mg per day lorazepam or equivalent)
• •Has an imminent risk of self-harm or harm to others
• •Has been treated with clozapine in the past 6 months prior to study start
• •Has been treated with lithium, valproate, lamotrigine, pregabalin, gabapentin, or carbamazepine in the past 12 weeks prior to study start
• •Has started treatment or has had a dose change of an (additional) antipsychotic, antidepressant,hypnotic or anxiolytic in the past 4 weeks prior to study start
• •Has had no demonstrated benefit of antipsychotic treatment within the previous five years