Binocular depth inversion as a paradigm of reduced visual information processing in prodromal state, antipsychotic-naïve and treated schizophrenia.

The binocular depth inversion illusion test (BDII) represents a sensitive measure of impaired visual information processing that manifests in various experimental and naturally occurring psychotic states. This study explores impairment of visual processing in different major psychiatric diseases investigating 313 subjects, suffering of either an initial prodromal state of psychosis (IPS) or a first-episode, antipsychotic-naïve paranoid schizophrenia (SZ-N) as well as short-term antipsychotically treated schizophrenia (SZ-T), major depression (MDD), bipolar disorder (BD), dementia (D), and healthy controls (HC). Patients suffering from either IPS, SZ-N or a SZ-T showed significantly higher scores of BDII compared to HC, indicating that visual processing is already disturbed at an early state of the disease.

Anandamide levels in cerebrospinal fluid of first-episode schizophrenic patients: impact of cannabis use.

Background: Previous studies have shown that cerebrospinal fluid (CSF) from schizophrenic patients contains significantly higher levels of the endogenous cannabinoid anandamide than does CSF from healthy volunteers. Moreover, CSF anandamide levels correlated inversely with psychotic symptoms, suggesting that anandamide release in the central nervous system (CNS) may serve as an adaptive mechanism countering neurotransmitter abnormalities in acute psychoses. In the present study we examined whether cannabis use may alter such a mechanism.

Disturbances of visual information processing in early states of psychosis and experimental delta-9-tetrahydrocannabinol altered states of consciousness.

Recent data on alterations of the endogenous cannabinoid system in schizophrenia have raised the question of its functional role in this disease. The psychoactive compound of Cannabis sativa, delta-9-tetrahydrocannabinol (Delta9-THC), has been shown to induce psychotic symptoms, but it is unknown to what extend prodromal states of psychoses are reflected by these experimental approaches. This study compares four groups of subjects: antipsychotic-naïve patients suffering from acute paranoid schizophrenic or schizophreniform psychosis (SZ), patients in the prodromal state (IPS), healthy controls without any pharmacological intervention (HC) and a second group of healthy volunteers who were orally administered synthetic Delta9-THC (Dronabinol) (HC-THC).