Seasonal trends in antidepressant prescribing, depression, anxiety, and self-harm in adolescents and young adults: an open cohort study using UK primary care data

BACKGROUND: Weather and seasons, or stressful periods associated with their education could affect young people's mental health. Members of a young person's advisory group asked us to investigate whether there are particular periods in the year when adolescents have more mental health issues. AIM: To examine whether there are different seasonal trends in antidepressant prescribing, depression, anxiety, and self-harm in adolescents compared with young adults in England. METHOD: We used information about antidepressant prescribing and mental health events between 2006 and 2019 from the QResearch database, which contains anonymised English primary care health records. We studied males and females in three age groups: 14-18 years (adolescents), 19-23 years and 24-28 years. We calculated monthly incidence rates and adjusted incidence rate ratios of prescriptions for the most commonly prescribed antidepressants (selective serotonin reuptake inhibitors) and records of depression, anxiety, and self-harm. RESULTS: The study included 5 081 263 people over 17.9 million person-years. Antidepressant prescribing, depression, and anxiety incidence rates were higher in autumn months for adolescents, but not for the older groups. Self-harm was lowest in August for adolescents, lower in July-December for 19-23-year-old females, and stable throughout the year for other groups. CONCLUSION: There were higher rates of antidepressant prescribing, depression, and anxiety at the start of the school year in adolescents. Support around mental health issues from GPs and schools should be focused during this period. Future studies should examine whether these results apply to younger children and develop interventions to lessen their impacts on adolescents.