The EXT-resARF model, in which all phenotypes loaded onto an externalizing (EXT) factor and SUDs loaded additionally onto a residual addiction risk factor (resARF), did not meet the threshold for good fit. The median loading on the residual ARF factor was low (median ƛ = 0.23) and the loadings were variable (SD of ƛ = 0.58). In addition, the residual variance of the opioid use disorder (OUD) indicator was negative.
