Modeling outcomes of partner violence using cusp catastrophe modeling

Research suggests that intimate partner violence (IPV) is a complex, nonlinear phenomenon. In addition to the violence trajectory itself, IPV decision-making, help-seeking and leaving are nonlinear processes as well. The purpose of this study was to determine whether outcomes were best modeled as cusp catastrophic phenomena with measures of violence nonlinearity and wife-perpetrated violence serving as bifurcation variables. This 12-week time series study was conducted among 200 adult women in violent relationships. Women completed daily assessments of household environment and marital relationship using Interactive Verbal Response; missing violence data was imputed using TISEAN software to maintain its nonlinear characteristics. LZ complexity, approximate entropy, and largest Lyapunov exponents were used as measures of violence nonlinearity. Asymmetry variables included violence frequency and severity as well as its onset and duration. Factor-analyzed outcomes included coping and appraisals, hope and support, symptomatology, functional status, readiness-for-change, and medical utilization. When severity of wife's violence and nonlinearity of husband's violence were used as bifurcation variables, cusp catastrophe modeling helped explain positive and negative coping as well as readiness-for-change. In conclusion, measures of nonlinearity of husband's violence and wife's violence contributed to the variance of three outcomes in cusp catastrophe modeling. Sudden changes in coping and readiness-for-change in IPV should be expected and knowledge of violence nonlinearity may have applications when working with violent couples.