Trajectories of loneliness during COVID-19 pandemic and associations with mental health and substance use

We examined patterns of longitudinal trajectories of loneliness during the COVID-19 pandemic using six time points (January 2020 [pre-pandemic] to March/April 2021) and whether trajectories were associated with psychological distress (depression/anxiety) and substance use (alcohol/cannabis) outcomes in Spring 2021. Participants were 644 young adults who completed online assessments. Outcomes were regressed on most-likely loneliness trajectory adjusting for pre-pandemic measures. Three loneliness trajectories varied from consistently lower to consistently higher. Pre-pandemic social support was associated with lower odds of a higher loneliness trajectory. Higher loneliness trajectories were associated with greater odds of past-month cannabis use compared to Low trajectories, but not significantly associated with depression, anxiety, or alcohol use in Spring 2021. Interventions addressing co-occurring loneliness and cannabis use are needed.