IntroductionFew studies are available on the health status of doctoral students. This position at the border between university studies and a professional activity presents specific risk factors, especially in terms of psychosocial constraints. The lockdowns implemented worldwide to control the COVID-19 pandemic are potentially worsening factors.MethodsAt Lyon 1 University, a systematic medical follow-up of first year PhD students had been set up by the occupational health service in 2019. In the context of the lockdown during the COVID-19 pandemic, a telephonic interview was proposed to the same PhD students in order to assess the impact of the lockdown on working conditions and health and to provide possible assistance. During this interview, a standardized questionnaire was used to collect information about the conditions during the lockdown, doctoral work during this period and the consequences on research progress, as well as possible financial difficulties due to the lockdown. In addition, questions were asked about the perceived general health conditions and consultation with a health practitioner during this period. The Patient Health Questionnaire (PHQ-9) and the Generalized Anxiety Disorder (GAD-7) were used to assess depression and anxiety. Questions on lifestyle during lockdown, changes in diet during the period, weight change, and changes in the quantity and quality of their sleep were also asked. Comparisons of perceived health status, the prevalence of anxiety and depression symptoms at baseline and during the follow-up survey were made by MacNemar Chi2 tests, as the data were repeated ones. The students were informed orally and in writing that their data would be entered anonymously into a computer and that they could have access to their data in accordance with the General Data Protection Regulation (GDPR). They were all informed by e-mail about the study results at the end of the study. The data collection process was registered with the National Institute for Health Data (INDS) and with the university's register under reference no. 2020/002 by the university's data protection officer in compliance with the French data protection laws (CNIL). The protocol was approved by the ethics committee of the Lyon University College of General Medicine (notification number: 2020-10-29-02).ResultsOf the 161 PhD students initially interviewed, 149 underwent a second interview. In total, 89.2% of the students assessed their health as good or very good. Regarding the answers to the GAD-7 questionnaire, 8.1% had a score equal to or higher than 10, corresponding to moderate to severe anxiety. Regarding the answers to PHQ-9, 19.6% of the PhD students had a score equal to or higher than 9 corresponding to moderate to severe depressive syndromes. The prevalence of an anxiety disorder was significantly associated with the absence of an outside private access in the place of residence during lockdown (75% vs. 37%), an increase in coffee consumption (33% vs. 5%), an increase in the quantity of food consumed (50% vs. 12%), weight gain (50% vs. 19%) and a deterioration in sleep quality (75% vs. 28%). The prevalence of a depressive symptom was significantly associated with lockdown in an urban area (89% vs. 70%), the occurrence of financial difficulties (7% vs. 1%), the consultation of a health professional during the period (34% vs. 15%), smoking cessation (14% vs. 1%), changes in the quantity (31% vs. 9%) and deterioration (59% vs. 25%) of the quality of sleep, and diet changes (66% vs. 43%). GAD-7 scores were unchanged for 90% of participants between the two surveys, but they were higher for 6.8% of doctoral students and lower for 2.7% (P=0.1). A deterioration of the PHQ-9 scores, i.e. higher scores in the second survey compared to the first, was observed for 15.5% of the PhD students while an improvement of the scores was observed for 1.4% (P=0.0001).DiscussionA number of studies have been published on the impact of lockdown on mental health, but few of them focused specifically on PhD students and even fewer were prospective studies. Their results are therefore difficult to compare with ours; they generally show GAD-7 and PHQ-9 scores that are similar to those of our population, or even higher. The impact of lockdown on the mental health of doctoral students highlighted in our study therefore justifies an appropriate follow-up of this population, particularly in the case of former psychiatric disorders.