Chronic Cannabis Users: A Model for Negative Symptoms in Schizophrenia

Summary

The aim of the current study is set out to find a human model for negative symptoms based on clinical observation that chronic cannabis users express negative symptoms and characterize by the same neurocognitive and electrophysiology characteristics like patient suffer from schizophrenia. Towards that end the first part of the study is set out to explore weather chronic cannabis user's express negative symptoms similar to patient suffer from schizophrenia. The second part of the study will explore the neurocognitive and electrophysiology characteristics of those cannabis users that express negative symptoms. This data will be compared to parallel data of schizophrenia patients with predominantly negative symptom.

Several lines of biological and genetic evidence support the cannabinoid hypothesis for schizophrenia. Particularly, it is most significant clinically that the possible involvement of the cannabinoid system in the neural basis for the negative symptoms. This hypothesis based on clinical findings that chronic cannabis use causes a combination of symptoms including apathy, avolition, lack of interest, passivity, and cognitive impairments, the so-called "amotivational syndrome," which resembles the core negative symptoms of schizophrenia in behavioral level as well as the brain level. Both are associated with the functions or integrity of the frontal lobe due to its role in creating self-directed behaviors, deficits in which may underlie alogia, anhedonia, and flat affect. Despite the aforementioned similarities, to date, there is no documentation for such a relationship. Recognition that chronic cannabis users share the same or similar constellation of symptoms and similar neurocognitive and electrophysiology characteristics could provide a key to develop a human model for negative symptoms and an essential tool to comprehensive understanding of the etiology of negative symptoms and development of an innovative therapy.

The investigators Hypothesize That Chronic Cannabis Users Would Express the Same Constellation of Behaviors as Negative Symptoms of Schizophrenia; as well as similar neurocognitive and electrophysiology characteristics

Conditions

• Chronic Cannabis Users
• Healthy Subjects

Interventions

PROCEDURE

Magnetoencephalograph (MEG)

Brain imaging device that records the magnetic fields in the brain.

BEHAVIORAL

Cambridge Neuropsychological Test Automated Battery (CANTAB).

the CANTAB is sensitive to cognitive changes caused by a wide range of Central Nervous System disorders and medication side-effects . The CANTAB uses a computer with a touch screen, and affords a rapid and non-invasive assessment of cognitive functions.

BEHAVIORAL

Experimental: Scale for the Assessment of Negative Symptoms (SANS) and the Positive and Negative Syndrome Scale (PANSS)

The SANS and PANSS scales asses the presence and severity of Positive and Negative of Schizophrenia

Sponsors & Collaborators

• Shalvata Mental Health Center

  lead OTHER

Principal Investigators

• Hilik Levkovitz, prof. · shalvata MHC

Study Design

Allocation

NON_RANDOMIZED

Purpose

DIAGNOSTIC

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

20 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2011-07-31

Primary Completion

2012-07-31

Countries

• Israel