Sleep disturbances are common among psychiatric patients. In fact, most psychiatric disorders are afflicted with sleep disturbances. Mechanistical underpinnings and associations between sleep disturbances and psychiatric conditions have been an active field of research. Individuals with alcohol or substance abuse reported disrupted sleep efficiency and continuity, as well as rates of insomnia as high as 72%. In schizophrenia, insomnia and other sleep-related abnormalities are also common, with prevalence rates of 30% to 80%. Moreover, individuals with mood disorders describe a range of difficulties with sleep continuity and quality. Another study in depressed individuals reported rates as high as 90% of reported sleep quality complaints. Similarly, anxiety disorders are highly associated with sleep disorders. The fact that sleep disturbance is a diagnostic symptom for disorders such as generalized anxiety disorder and post-traumatic stress disorder (PTSD) underpins the relationship between anxiety and sleep. In PTSD for example, difficulty initiating and maintaining sleep and nightmares affect approximately 70% of individuals afflicted with this disorder. Reexperiencing in the form of distressing dreams and intrusive trauma memories prior to initiating sleep are commonly reported in this group. Taken together, these reports show that sleep problems are common in psychiatric patients. Some theoretical models suggest that certain sleep alterations are specific for certain mental disorders. Newer models, however, suggest a transdiagnostic or dimensional understanding of sleep in mental disorders, assuming sleep as an underlying dimension of mental disorders, with the same sleep alterations occurring in different mental disorders. Few studies comprise large enough numbers to compare different psychiatric diagnoses, however, and thus, few data exist on the specificity of various sleep abnormalities. In a notable exception, a meta-analysis investigated sleep disturbances across psychiatric disorders, reviewing studies using polysomnographic measurements. The authors found that no single sleep variable appeared to have absolute specificity for any particular psychiatric disorder and that patterns of sleep disturbances associated with categories of psychiatric disorders were observed. Additionally, the subtypes of diagnosis groups often differed in their profiles of sleep alterations. Thus, these results support the transdiagnostic view of sleep disturbances in mental disorders. In the light of these findings, however, it is interesting that the period just prior to sleep onset has recently received increased research and clinical interest. Pre-sleep cognitive activity of individuals suffering from insomnia has been shown to be more focused on worries, problems and noises in the environment and less focused on nothing in particular, compared to good sleepers. There is also evidence that rumination prior to sleep is associated with sleep disturbance (increased sleep onset latency, reduced sleep quality, reduced sleep efficiency, and increased wakefulness after sleep onset). Identification of potential disorder-specific as well as transdiagnostic pre-sleep processes would be helpful for diagnosing and treating patients. This is particularly important considering the heavy personal burden associated with psychiatric disorders and sleep disturbances. Most of the studies investigating sleep disturbances in psychiatric disorders have been conducted in psychiatric outpatients. Psychiatric inpatients and the even more severely afflicted patients who often suffer from comorbid diagnoses and possible additional social problems, have so far been mostly excluded. There are a few studies, which investigated sleep problems in psychiatric inpatients and/or patients with severe mental illness. Furthermore, although the period just prior to sleep onset has recently received increased research and clinical interest, a systematic investigation of individuals with diagnosed psychiatric disorders in terms of this specific sleep characteristic is lacking so far. The present study therefore aims to help fill this gap and study sleep problems, including pre-sleep processing in psychiatric inpatients. Additionally, studies investigating sleep disturbances using samples of patients with different psychiatric disorders are lacking. Thus, in order to understand the differences in sleep disturbances between different psychiatric diagnoses or symptom clusters, different studies have to be compared. Since these studies often differ in the samples and methods used, conclusions drawn from these comparisons are limited. For this reason, studies using samples of psychiatric patients with a wide range of psychiatric disorders are warranted.

For this study, participants will be recruited from the inpatient units of the Psychiatric University Hospital Zurich (PUK). Consultant psychiatrists and psychologists, as well as nursing personnel in the inpatient units of the PUK will support recruitment and one or two master students will help organise the study. All patients eligible for the study will be recruited consecutively. The applicant and master's students enrolled in the project will screen newly admitted psychiatric inpatients for inclusion and exclusion criteria in the electronic patient files. The information needed for the screening is part of standard assessments at the hospital. The treating psychologists or physicians will then be contacted directly by the applicant or master's students. The treating psychologists and physicians will invite the patients who meet the inclusion and exclusion criteria to the study. Prior to the first session, the applicant or master's students will use the patient's electronic file to document medical information, such as medical history, current primary diagnosis, and current medication. The first session, which will be led by the applicant or master's students, will consist of informed consent, a clinical interview, and a first set of self-report questionnaires, which will assess primary psychiatric diagnoses, measure demographic and personal information, sleep disorders, sleep characteristics, several psychological variables (such as emotional regulation, rumination, and mindfulness) and current symptom severity of the primary diagnosis. A sub-sample of patients will receive a sleep diary and a Fitbit Charge 2 tracker as well as information regarding its application. They will wear the Fitbit tracker on the wrist of their non-dominant hand at all times for a week (except during showers and / or charging). A week later, the questionnaires and/or diary and Fitbit tracker will be collected. Additionally, patients will be asked if they have any questions or whether they ran into any problems. After data collection is completed, each patient will receive participant reimbursement of 30 Swiss francs (CHF) for their participation in the study.