Exploring the Mechanism Between Length of Stay in the U.S. and Immigrant Mental Health: A Multiple Mediation Analysis

Background and Purpose: Assimilation theory suggests that the length of stay of immigrants in the U.S. facilitates adaptation, which presumably bolsters their mental health.  However, empirical studies indicate immigrants’ mental health worsens over time. This study aims to investigate the underlying mechanisms which influence the impact of length of stay on mental health outcomes among Latino and Asian adult immigrants. The stress process model suggests the adverse effects of persistent stressors (e.g. perceived discrimination) on mental health. On the other hand, the strength-based model informs the positive effects of family and social support on immigrants’ psychological well-being. Therefore, we examined the potential mediating roles of acculturative stress, perceived discrimination, family cohesion, and social support. We hypothesized that a) the length of stay in the U.S. would be associated with higher levels of psychological distress through increased perceived discrimination, and b) the length of stay in the U.S. would be associated with lower levels of psychological distress through decreased acculturative stress, as well as increased family cohesion and social support.

Methods: Using data from the National Latino and Asian American Study (NLAAS), our analytical sample consisted of 2,701 Latino and Asian first and second-generation immigrant adults living in the U.S. The dependent variable, psychological distress, was measured by the 10-item Kessler Psychological Distress Scale (K10). K10 measures past-year mental health problems, such as anxiety or mood disorders. The mediating variables were measured by researcher-constructed scales based on the items available in the survey. These scales were used in previous studies and had acceptable to excellent reliability in our study sample (α=.66-.93). We conducted multiple mediation analysis with full information maximum likelihood estimator using Mplus 6.0 to simultaneously estimate multiple mediation effects. When conducting the mediation analysis, bootstrap bias-corrected confidence intervals (95% CIs) were obtained, with the number of bootstrapping set to 5000.

Results: There was a significant total indirect effect from time in the U.S. and psychological distress was 0.094 (95% CI=0.013, 0.161). The association between time in the U.S. and psychological distress was significantly mediated by acculturative stress (b=-.05, 95% CI=-0.09, -0.02), perceived discrimination (b=.06, 95% CI =0.03- 0.11), and family cohesion (b=.05, 95% CI=0.02-0.19). Consistent with our hypotheses, length of stay in the U.S. was associated with higher perceived discrimination, which in turn was associated with higher levels of psychological distress.  Longer length of stay in the U.S. was also associated with lower acculturative stress, which predicted lower levels of psychological distress. Unexpectedly, longer stay in the US was associated with a lower level of family cohesion, which was subsequently associated with greater psychological distress.

Conclusions/implication: Overall, longer length of stays in the U.S. adversely impact mental health outcomes for Asian and Latino immigrant adults.  Although adults with longer length of stays experience less acculturative stress, this benefit was outweighed by the negative impact of discrimination and family discord.  These findings represent the complexities of immigrant experiences and suggest the need for interventions to support immigrant families, as well as policies to reduce discrimination.