Cannabidiol (CBD) is a component of herbal cannabis that is present in varying concentrations in cannabis extracts. CBD has been shown to produce central effects including hypnotic, anticonvulsive, anxiolytic and neuroprotective effects.The investigators hypothesize that treatment with CBD will result in: 1) Improvement evidenced by a reduction in scores on the Positive and Negative Syndrome Scale for Schizophrenia (PANSS), 2) Improvement evidenced by a reduction in the Clinical Global Impression of Severity scale (CGI); Secondary Hypothesis: 1) Greater improvement in functioning as measured on the "Patient Assessment of Own Functioning Inventory: (PAOFI) and the Quality of Life Scale (QLS) In this 2 period cross over design, subjects will be randomized in a 1:1 ratio to receive either: Order 1: CBD (Period 1) followed by placebo (Period 2) or Order 2: Placebo (Period 1) followed by CBD (Period 2) under double-blind conditions. The 2 study periods will be separated by a washout of at least 2 weeks. During each period subjects will receive study medications (CBD \[total 800mg/day\] or placebo) for a period of 4 weeks.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
18
Connecticut Mental Health Center
New Haven, Connecticut, United States
VA Connecticut Healthcare System
West Haven, Connecticut, United States
Positive and Negative Syndrome Scale (PANSS) Over Time
The Positive and Negative Syndrome Scale is a 30-item scale to assess both the positive and negative symptom symptoms of schizophrenia. The range total score is 30-210. An improvement in symptoms is reflected by a lower score.
Time frame: Completed each time subject is seen over 10 weeks (screening, period 1 baseline, period 1 week 1, period 1 week 2, period 1 week 3, period 1 week 4, period 2 baseline, period 2 week 1, period 2 week 2, period 2 week 3, period 2 week 4)
Clinical Global Impression of Severity Scale Over Time
Clinical Global Impression of Severity Scale score is a global rating of improvement scale, which requires subjects to rate their degree of improvement on a 7-point scale. The total range score is 1-7. A reduction in scores indicates improvement.
Time frame: Completed each time subject is seen over 10 weeks (screening, period 1 baseline, period 1 week 1, period 1 week 2, period 1 week 3, period 1 week 4, period 2 baseline, period 2 week 1, period 2 week 2, period 2 week 3, period 2 week 4)
Patient Assessment of Own Functioning Inventory (PAOFI) Over Time
The PAOFI measures subjects' perceptions of functioning when performing everyday tasks and activities that reflect cognitive strengths and weaknesses. Subjects rate each item on a scale ranging from 0 (almost never) to 5 (almost always). The total score is the sum of the responses to each item (score of 0 to 160). High scores on the PAOFI subscales are indicative of poor perceived cognitive functioning. This scale was modified to remove 3 items- so the highest possible score is 145 for this outcome measure.
Time frame: Completed each time subject is seen over 10 weeks (screening, period 1 baseline, period 1 week 1, period 1 week 2, period 1 week 3, period 1 week 4, period 2 baseline, period 2 week 1, period 2 week 2, period 2 week 3, period 2 week 4)
Quality of Life Scale (QLS) Over Time
The Quality of Life Scale (QLS) is a 21-item scale rated from a semi structured interview, each item is rated 0-6. The specific descriptors vary among items, but the high end of the scales (scores of 5 and 6) reflects normal or unimpaired functioning, and the low end of the scales (scores of 0 and 1) reflects severe impairment of the function in question. A highest score of 126 would indicate unimpaired functioning.
Time frame: Completed each time subject is seen over 10 weeks (screening, period 1 baseline, period 1 week 1, period 1 week 2, period 1 week 3, period 1 week 4, period 2 baseline, period 2 week 1, period 2 week 2, period 2 week 3, period 2 week 4)
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