Background The COVID-19 pandemic may impact mental health outcomes differentially based on an inidivdual’s capital, i.e. resources used to maintain and enhance health. This study examined changes in depression and anxiety symptoms before and during the pandemic, and assessed their association with different elements of capital. Methods Data from 65,854 individuals (Mage=50.4, SDage=12.0) from the Lifelines COVID-19 cohort were used. Baseline mental health symptoms were on average measured 4.7 (SD = 1.1) years before the first COVID-19 measurement wave (T1), and subsequent waves were (bi)weekly (March 30 — August 05, 2020). Mental health symptom trajectories were estimated using a two-part Latent Class Growth Analysis (cutoff=2 symptoms), and class membership was predicted by several elements of economic (education, income, and occupation) and person capital (neuroticism). Results Most individuals were unlikely to report □2 symptoms of depression (80.6%) and anxiety (75.9%), but small stable-high classes for both conditions were identified (1.6% and 6.7%, respectively). Compared to T0, T1 showed increases in the mean number of symptoms (Mdep_t0=4.1 vs Mdep_t1=4.7, Manx_t0=4.2 vs Manx_t1=4.3) and probability of reporting symptoms (Probdep_t0=0.65 vs Probdep_t1=0.96, Probanx_t0=0.70 vs Probanx_t1=0.92). Lower income (ORdep=1.10; 95%CI:1.05-1.16; ORanx=1.05; 95%CI:1.02-1.07) and higher neuroticism (ORdep=1.10; 95%CI:1.09-1.11; ORanx=1.08; 95%CI:1.08-1.09) increased the odds of being in both stable-high classes. Low education increased the odds of being in the stable-high depression class (ORdep=1.46; 95%CI:1.07-1.99), and higher occupation increased the odds of being in the stable-high anxiety class (ORanx=1.06; 95%CI:1.03-1.09). Conclusion Overall, a minority of individuals, who generally possessed less capital, reported an increase in symptoms of depression or anxiety. Key message Inidividuals with less capital, i.e. resources, generally experienced more symptoms of depression and anxiety, which stresses the ...