The acute effects of synthetic intravenous Delta9-tetrahydrocannabinol on psychosis, mood and cognitive functioning.
Morrison et al.·Psychological MedicineImpact 4.3
Clear benefitGRADEModerate304 citations
Samplen = 22 Pat.
DurationMeasurements up to 120 min…
ControlPlacebo
EndpointPANSS
Blindingdoppelblind
DesignRCT (doppelblind, placebo-kontrolliert)
Cannabinoidthc
Max. dose2.5 mg
Routeinhalativ
”Key finding
Intravenous THC induced transient positive psychosis symptoms as well as anxiety and cognitive impairments compared to placebo.
Summary
n=22 healthy adult men (age 28±6 years), IV THC 2,5 mg vs. placebo (double-blind); THC induced positive psychotic symptoms (PANSS, CAPE: significantly increased vs. placebo), increased anxiety ratings, worsened neuropsychological performance (RAVLT, Digit Span, Verbal Fluency); no association between psychotic symptoms and anxiety intensity (r not significant) or working memory deficits — THC-induced transient psychosis is independent of anxiety and cognitive impairment.
P
PopulationHealthy adult men, n=22, average age 28±6 years
I
InterventionIntravenous synthetic THC (Δ9-tetrahydrocannabinol), 2,5 mg i.v., single dose
C
ControlPlacebo (i.v.)
O
OutcomeTHC induced significant positive psychosis symptoms (PANSS); no correlation between psychotic symptoms and anxiety level or neuropsychological deficits
Confidence in the evidence
Very lowLowModerateHigh
Moderate
The third of four GRADE levels, the effect estimate is probably reliable.
Downgraded for
Imprecision
Quality profile
Sample size★★★★★
BlindingDouble-blind
Effect sizeClear benefit
Citations / year★★★★★
Authors
Morrison PD, Zois V, McKeown DA, Lee TD, Holt DW, Powell JF, Kapur S, Murray RM.
<h4>Background</h4>Recent work suggests that heavy use of cannabis is associated with an increased risk of schizophrenia-like psychosis. However, there is a dearth of experimental studies of the effects of the constituents of cannabis, such as Delta9-tetrahydrocannabinol (THC). In a study of intravenous (i.v.) synthetic THC in healthy humans, we aimed to study the relationship of the psychotic symptoms induced by THC to the consequent anxiety and neuropsychological impairment.<h4>Method</h4>Twenty-two healthy adult males aged 28+/-6 years (mean+/-s.d.) participated in experimental sessions in which i.v. THC (2.5 mg) was administered under double-blind, placebo-controlled conditions. Self-rated and investigator-rated measurements of mood and psychosis [the University of Wales Institute of Science and Technology Mood Adjective Checklist (UMACL), the Positive and Negative Syndrome Scale (PANSS) and the Community Assessment of Psychic Experiences (CAPE)] were made at baseline and at 30, 80 and 120 min post-injection. Participants also completed a series of neuropsychological tests [the Rey Auditory Verbal Learning Task (RAVLT), Digit Span, Verbal Fluency and the Baddeley Reasoning Task] within 45 min of injection.<h4>Results</h4>THC-induced positive psychotic symptoms, and participant- and investigator-rated measurements of these were highly correlated. Participants showed an increase in anxiety ratings but there was no relationship between either self- or investigator-rated positive psychotic symptoms and anxiety. THC also impaired neuropsychological performance but once again there was no relationship between THC-induced positive psychotic symptoms and deficits in working memory/executive function.<h4>Conclusions</h4>These findings confirm that THC can induce a transient, acute psychotic reaction in psychiatrically well individuals. The extent of the psychotic reaction was not related to the degree of anxiety or cognitive impairment.