## 1 Introduction  
Psychiatric disorders are among the top leading causes of burden worldwide, and around 450 million people in the world are estimated to suffer from these disorders according to the World Health Organization (WHO) [1]. Among severe mental disorders, major depressive disorder (MDD) is the most prevalent, affecting more than 250 million people worldwide [2], and represents the second-leading cause of disability globally [3]. Furthermore, during the COVID-19 pandemic many determinants of poor mental health were exacerbated, leading to a stark rise in depressive and anxiety disorders globally in 2020 [4]. While the molecular underpinnings of psychiatric disorders are still largely elusive, their development has been shown to be the result of a complex interplay between genetic and environmental factors. Indeed, psychiatric disorders show different degrees of heritability and genome-wide association studies (GWAS) have started to identify a number of genetic determinants associated with predisposition to these disorders [5; 6; 7]. Severe psychiatric disorders such as MDD, schizophrenia (SCZ) and bipolar disorder (BD) are associated with significant excess mortality as well as decreased life expectancy [8; 9]. A large body of evidence suggests that this excess mortality is largely accounted for by a higher prevalence of comorbid chronic disorders compared to individuals without mental illness [10; 11]. In particular, cardiometabolic disorders with an inflammatory component, such as cardiovascular and metabolic disorders, present significantly higher incidence in patients with psychiatric disorders than in the general population [12]. Physical comorbidities in patients with psychiatric disorders have been found to double the risk of premature mortality compared to the general population [9; 13]. Different determinants such as lifestyle factors (e.g., diet, physical activity, alcohol intake) as well as adverse effects of psychotropic medications, have been suggested to contribute to the observed comorbidity between psychiatric and cardiometabolic disorders [14]. However, since both groups of disorders show significant heritability, shared genetic determinants might also play a role [15]. This hypothesis is corroborated by the fact that comorbidities have also been reported in adolescents and drug naive patients [16; 17], thus suggesting the existence of common pathophysiological processes, as well as potential genetic links between these conditions. Psychiatric disorders also show relevant comorbidity with sleep disorders and disturbances of the circadian rhythms, which are 24-h rhythms autonomously driven by the internal biological clock and synchronized daily by environmental signals [18]. Psychiatric disorders have been associated with insomnia, hypersomnia, circadian rhythm disruption [19] as well as the evening circadian chronotype [20] (with the latter defined as an individual variation in the preferred timing of the sleep-wake cycle, associated with variations of physiological functions, such as body temperature and hormone secretion). As in the case of comorbidity with cardiometabolic disorders, genetic factors have been suggested to play a role in the molecular mechanisms driving the association between sleep and severe mental disorders such as MDD, BD and SCZ [21], post-traumatic stress disorder (PTSD) or neurodevelopmental disorders such as attention-deficit/hyperactivity disorder (ADHD) [22]. However, there is scarce information regarding other psychiatric disorders for which genetic data are available such as anorexia nervosa (AN) or Touret syndrome (TS). In addition, no study has conducted a comprehensive analysis of psychiatric, cardiometabolic and sleep traits in order to assess whether it is possible to identify clusters of genetically correlated traits.