The linear and curvilinear relationships between assertiveness and mental health: a cross-cultural perspective

Eurocentric research suggests that higher assertiveness is associated with better mental health. However, it remains unclear whether this linear relationship applies to collectivistic cultures. This cross-cultural study examined the linear and curvilinear relationship between assertiveness and mental health among 410 Chinese and 360 US adults. We examined linear, quadratic, and cubic relationships through hierarchical regression analyses. In the Chinese group, results indicated a significant cubic relationship between assertiveness and both depression (R-2 = 8.82%, p < .001) and aggression (R-2 = 2.46%, p < .001), showing that an optimal assertiveness level was associated with lower depression and aggression. In the US group, higher assertiveness was associated with lower depression (R-2 = 4.24%, p < .001), but not aggression. This study highlights cultural variations in assertiveness-mental health relationships. Mental health professionals should consider cultural norms while providing assertiveness training to diverse individuals.