terminated

This study was designed to compare the [123]I-CNS 1261 binding to NMDA receptor between healthy volunteers and different subgroups of schizophrenic patients. Investigation of the potential influence of antipsychotic and concomitant medication on [123I] CNS 1261 binding is also relevant.Fifteen healthy subjects (male and female of non-child bearing potential) will be recruited and 40 schizophrenic patients divided in 3 subgroups as indicated before: Subgroup a) treatment-naive, (n=10); Subgroup b) on stable treatment with risperidone (without criteria of deficit syndrome on the SDS scale, (n=15);Subgroup c) on stable treatment with risperidone fitting criteria of deficit syndrome on the SDS scale, (n=15).

Inclusion criteria:

• Right-handed
• Smoker
• Healthy volunteer or schizophrenic patients as diagnosed by DSM IV criteria.
• Treatment naive patients or with Risperidone treatment for 2 months that have not received any depot neuroleptic during the last year.
• Women of childbearing potential must agree to acceptable method of birth control.

Exclusion criteria:

• Any clinically or laboratory significant abnormality.
• Subjects receiving a radiation dose from other activities of more than 10 mSv over any 3 year period.
• Heart pacemaker, metallic prosthesis or other metallic body implants.
• History or presence of CNS conditions.
• History of substance dependence.
• History of or suffers from claustrophobia.
• Positive test for HBV (hepatitis B virus), HCV (hepatitis C virus) or HIV.
• Pregnant or lactating women.