highly significantp < 0.001
The unconditioned models (null models) of the multilevel analyses showed that a highly significant proportion of variance was determined by the wave (mental well‐being 20%, somatisation 38%, anxiety 28%, depression 22% and PTSD symptoms 28%; Wald Z = 7.75, p < 0.001), with the proportion of variance due to the individual level also being significant (mental well‐being 80%; Wald Z = 8.83, p < 0.001; somatisation 62%, Wald Z = 5.71, p < 0.001; anxiety 72%, Wald Z = 6.35, p < 0.001; depression 78%, Wald Z = 6.72, p < 0.001; and PTSD symptoms 72%, Wald Z = 6.37, p < 0.001).