Child abuse and cannabis use interact synergistically and increase the risk for positive psychotic symptoms significantly more than either factor alone.
Summary
In 2 population cohorts (n=1.636 + n=4.842) the synergistic psychosis-risk effect of cannabis + childhood traumatization increased with decreasing age [interaction term b=−0.006, 95% CI −0.010 to −0.002, p=0.004]; finding replicated in NEMESIS [χ²(3)=8.08, p=0.04] — cannabis risk particularly elevated in adolescents with trauma exposure.
P
PopulationPopulation-based samples: Greek National Perinatal Study (n=1.636) and Dutch NEMESIS study (n=4.842); children/adolescents or adults with and without child abuse and cannabis use
I
InterventionCannabis use (lifetime use or use at the age of 19 years)
C
ControlNo cannabis use (reference group within the cohorts)
O
OutcomeSignificant interaction between child abuse and cannabis use on psychosis risk in both cohorts [Greek study: F(2,1627)=4,18, p=0,02; NEMESIS: χ²(3)=8,08, p=0,04]
Confidence in the evidence
Very lowLowModerateHigh
Low
The second of four GRADE levels, the effect estimate is of limited reliability.
Quality profile
Sample size★★★★★
Blinding—
Effect sizeClear benefit
Citations / year★★★★★
Authors
Konings M, Stefanis N, Kuepper R, de Graaf R, ten Have M, van Os J, Bakoula C, Henquet C.
<h4>Background</h4>There may be biological plausibility to the notion that cannabis use and childhood trauma or maltreatment synergistically increase the risk for later development of psychotic symptoms. To replicate and further investigate this issue, prospective data from two independent population-based studies, the Greek National Perinatal Study (n=1636) and The Netherlands Mental Health Survey and Incidence Study (NEMESIS) (n=4842), were analyzed.<h4>Method</h4>Two different data sets on cannabis use and childhood maltreatment were used. In a large Greek population-based cohort study, data on cannabis use at age 19 years and childhood maltreatment at 7 years were assessed. In addition, psychotic symptoms were assessed using the Community Assessment of Psychic Experiences (CAPE). In NEMESIS, the Composite International Diagnostic Interview (CIDI) was used to assess psychotic symptoms at three different time points along with childhood maltreatment and lifetime cannabis use.<h4>Results</h4>A significant adjusted interaction between childhood maltreatment and later cannabis use was evident in both samples, indicating that the psychosis-inducing effects of cannabis were stronger in individuals exposed to earlier sexual or physical mistreatment [Greek National Perinatal Study: test for interaction F(2, 1627)=4.18, p=0.02; NEMESIS: test for interaction χ2(3)=8.08, p=0.04].<h4>Conclusions</h4>Cross-sensitivity between childhood maltreatment and cannabis use may exist in pathways that shape the risk for expression of positive psychotic symptoms.