A recent Suicidal Drive Hypothesis posits that psychotic experiences (PEs) may serve to externalise internally generated and self-directed threat (i.e. self-injurious/suicidal behaviour (SIB)) in order to optimise survival, however, it must first be demonstrated that such internal threat can both precede and inform PEs. The current study conducted the first known bi-directional analysis of SIB and PEs to test whether SIB could be considered as a plausible antecedent for PEs. Prospective data were utilised from the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally-representative birth cohort of 2,232 twins, that captured SIB (any self-harm or suicidal attempt) and PEs at ages 12 and 18 years. Cross-lagged panel models demonstrated that the association between SIB at age 12 and PEs at age 18 was as strong as the association between PEs at age 12 and SIB at age 18. Indeed, the best representation of the data was a model where these paths were constrained to be equal (OR=2.48, 95% CI=1.63–3.79). Clinical interview case notes for those who reported both SIB and PEs at age 18, revealed that PEs were explicitly characterised by SIB/threat/death related content for 39% of cases. These findings justify further investigation of the suicidal drive hypothesis.
|Journal||Development and Psychopathology|
|Publication status||Accepted/In press - 11 Aug 2020|
- birth-cohort; cross-lagged panel analysis; psychosis; self-harm; self-injurious behaviour
Murphy, J., Shevlin, M., Arsenault, L., Bentall, R., Caspi, A., Danese, A., Hyland, P., Moffitt, T., & Fisher, H. (Accepted/In press). Externalising the threat from within: A new direction for researching associations between suicide and psychotic experiences. Development and Psychopathology.