Background Since the COVID‐19 pandemic reached Japan in 2020, the country has faced an unprecedented increase in suicide rate and school refusal among adolescents, as well as increased rates of depression and anxiety among young people. However, the effects of the COVID‐19 pandemic on adolescents in terms of changes in habits, the development of mental disorders, social isolation, and suicidal ideation remain largely unclear. Case Presentation We examined three cases of university students who changed their habits during the COVID‐19 pandemic and developed mental disorders. All three cases had similar habitual changes, experienced loneliness, and developed depression and circadian rhythm sleep–wake disorder. Their habitual changes were delayed sleep and wake times, delayed first mealtime, a tendency to eat before sleeping, decreased social contact, increased digital media usage, and a tendency to use digital media before going to bed. We established a model of increasing mental health difficulties, school refusal, and suicidal ideation during the COVID‐19 pandemic. Conclusion This report suggests possible approaches for preventing a decline in mental health during the COVID‐19 pandemic among university students.

BackgroundSuicidal ideation is closely related to severe suicidal behaviour and is an important predictor of suicide attempt and completion, including in older people. Older people tend to have many opportunities to be conscious of death, and may have vague suicidal ideation because of various loss experiences, even if they are not depressed. We hypothesised that suicidal ideation among older people might be a risk factor for later transition to depression. The present study aimed to clarify risk factors that predict the incidence of depression in older people 3 years post‐baseline in a rural area of Japan, and to examine the subsequent course of depression among non‐depressed older people with suicidal ideation.MethodsIn 2015 and 2018, survey questionnaires were mailed to residents aged 65 years and over living in a rural area in Japan. Participants were divided into a depression group and a non‐depression group using 15‐item Geriatric Depression Scale scores 3 years post‐baseline. Logistic regression analysis was used to identify predictive factors of late‐life depression 3 years post‐baseline.ResultsWe received 597 valid responses, with a 3‐year follow‐up rate of 78.8%. Regarding suicidal ideation, 6.7% of non‐depressed older people exhibited suicidal ideation at baseline. Of these, 9.8% exhibited depression after 3 years post‐baseline. Logistic regression analysis indicated that development of late‐life depression is significantly associated with suicidal ideation, being female, and poor health‐related quality of life (HRQOL).ConclusionsThe results revealed that suicidal ideation, being female, and poor HRQOL were predictive factors of the development of late‐life depression 3 years post‐baseline in a rural area of Japan. These findings provide novel information regarding the transition to depression among community‐dwelling older people who are not depressed but have suicidal ideation. Whereas suicidal ideation is considered to be a symptom of depression, the current results suggest that suicidal ideation may precede depression in some older people.