Introduction There are few published empirical data on the effects of COVID‐19 on mental health, and until now, there is no large international study. Material and methods During the COVID-19 pandemic, an online questionnaire gathered data from 55,589 participants from 40 countries (64.85% females aged 35.80 ± 13.61; 34.05% males aged 34.90±13.29 and 1.10% other aged 31.64±13.15). Distress and probable depression were identified with the use of a previously developed cut-off and algorithm respectively. Statistical analysis Descriptive statistics were calculated. Chi-square tests, multiple forward stepwise linear regression analyses and Factorial Analysis of Variance (ANOVA) tested relations among variables. Results Probable depression was detected in 17.80% and distress in 16.71%. A significant percentage reported a deterioration in mental state, family dynamics and everyday lifestyle. Persons with a history of mental disorders had higher rates of current depression (31.82% vs. 13.07%). At least half of participants were accepting (at least to a moderate degree) a non-bizarre conspiracy. The highest Relative Risk (RR) to develop depression was associated with history of Bipolar disorder and self-harm/attempts (RR = 5.88). Suicidality was not increased in persons without a history of any mental disorder. Based on these results a model was developed. Conclusions The final model revealed multiple vulnerabilities and an interplay leading from simple anxiety to probable depression and suicidality through distress. This could be of practical utility since many of these factors are modifiable. Future research and interventions should specifically focus on them.

Antidepressants of all types showed limited efficacy in juvenile depression, but fluoxetine might be more effective, especially in adolescents. Studies in children and in severely depressed, hospitalised or suicidal juvenile patients are needed, and effective, safe and readily accessible treatments for juvenile depression are urgently required.

Despite the common use of MDMA (ecstasy) in the UK, the mechanism underlying associated potentially fatal cerebral oedema is unclear. We used a new experimental approach working directly with clubbers to perform a study on 30 (17 male) experienced clubbers (mean 6.6 years of clubbing). Pre- and post-clubbing measurements were performed to compare plasma levels of pituitary hormones (vasopressin, oxytocin), plasma and urine osmolality, urinary pH, and plasma sodium and urea. Ecstasy consumption was confirmed by using urinary drug screening pre- and post-clubbing. MDMA was detected in the urine samples of 17 subjects, three of which tested positive during pre-clubbing tests. Mean plasma vasopressin concentration increased in the MDMA group (1.28 +/- 0.29 to 1.43 +/- 0.41 pmol/l), but fell in other participants (1.23 +/- 0.42 to 1.16 +/- 0.0.34 pmol/l). Similarly, mean plasma oxytocin concentrations increased after ingestion of MDMA (2.02 +/- 0.29 to 2.43 +/- 0.24 pmol/l), but fell in the group that did not use MDMA (2.17 +/- 0.36 pmol/l to 1.89 +/- 0.37 pmol/l). There was a significant group by time interaction for plasma osmolality and plasma sodium (p = 0.001 and p = 0.003, respectively) and between change in urinary osmolality (p < 0.001) and MDMA use, with the pattern of change being consistent with the induction of inappropriate vasopressin secretion (also known as SIADH) by MDMA. This report demonstrates SIADH in ecstasy-using "clubbers", which has important clinical implications.