“…The findings of this study are in parallel with and extend previous research on the bidirectional relationship between anxiety and depression, and insomnia. Two retrospective investigations [8,9] and two prospective studies [7,10] have previously investigated the direction of risk between, on one hand, anxiety and depression and, on the other hand, insomnia. The results from this study, in combination with evidence from previous research, suggest clearly that anxiety may be a risk factor for future insomnia, but also that insomnia may increase the risk for future anxiety [7][8][9][10]14].…”