Research
Sleep plays a fundamental role in both emotional and cognitive functioning. At the same time, nearly all individuals with psychiatric disorders experience pronounced sleep disturbances. Our research aims to elucidate the role of sleep within the broader context of psychopathology and psychotherapy, with the overarching goal of translating insights from basic science into clinical practice.
Sleep and Psychopathology: Mechanisms
Despite the well-established association between sleep and psychopathology, the underlying mechanisms remain insufficiently understood. A major line of our research therefore examines how sleep, neuronal activity during sleep—and disruptions in sleep—contribute to the development and maintenance of psychological symptoms and mental disorders.
Trauma. One central focus of our research lies in the interplay between sleep and trauma. Using controlled trauma-analogue paradigms and naturalistic longitudinal studies in rescue service trainees, we investigate how sleep influences the processing of aversive experiences (Wilhelm et al., 2021; Azza, Kammerer et al., 2026; Kammerer et al., ongoing). Our work has demonstrated a bidirectional relationship: aversive experiences substantially disrupt sleep and alter oscillatory activity, while sleep—compared to wakefulness—and trauma-induced changes in sleep following exposure to aversive events shape their long-term processing (Wilhelm et al., 2021; Azza, Kammerer et al., 2026). In ongoing studies, we are now testing whether experimentally enhancing sleep parameters implicated in trauma processing, such as spindle activity, through closed-loop auditory stimulation can facilitate the processing of aversive experiences and reduce the development of intrusions (Lehmann-Grube, Kammerer, Wilhelm-Groch; in collaboration with Hong-Viet Ngo-Dehning, University of Essex).
Nightmares. Nightmares are common in both the general population and in psychiatric populations and are often associated with nocturnal hyperarousal. We are interested in further characterizing the phenomenon of hyperarousal, which is not only relevant in the context of nightmares but also represents a transdiagnostic feature across many mental disorders. Our findings indicate that hyperarousal shows a trait-like pattern in individuals with frequent nightmares and decreases following psychotherapy (Sayk et al., 2024). To better understand its mechanistic role in the etiopathogenesis of nightmares, we aim to experimentally manipulate hyperarousal using novel approaches such as targeted memory reactivation (TMR) (Sayk et al., 2025).
Improving Sleep to Reduce Psychopathology
Sleep disturbances are highly prevalent in psychiatric disorders, and growing evidence suggests that improving sleep may have therapeutic benefits beyond insomnia. In the second main focus of our research, we investigate (i) how existing treatments can be augmented or new interventions developed to target insomnia, and (ii) how targeted sleep interventions can reduce psychopathology across diagnostic groups and symptoms beyond insomnia. For example, we examine whether integrating metacognitive elements enhances cognitive-behavioral therapy for insomnia (CBT-I) in psychiatric patients (Schaich) and whether hypnotherapy reduces both sleep disturbances and depressive symptoms (Reutter). A large multicenter study further tests whether early treatment of sleep problems after trauma influences symptom trajectories and reduces posttraumatic stress disorder (PTSD) risk (Sayk, Lehmann-Grube et al., 2024). Finally, our work in individuals with borderline personality disorder shows that imagery rehearsal therapy (IRT) alleviates not only nightmares but also trauma-related and anxiety symptoms (Sayk et al., 2025).
Sleep-Based Psychotherapy Augmentation
Psychotherapy is effective for many individuals, yet a substantial proportion of patients do not achieve full remission, highlighting the need for feasible and safe methods to enhance therapeutic outcomes. Building on our finding that sleep is a critical period for consolidating trauma-focused therapy content in healthy participants (Azza et al., 2022), we aimed to directly strengthen consolidation processes occurring during sleep. One promising method is targeted memory reactivation (TMR), which leverages fundamental sleep-dependent memory mechanisms by pairing a contextual cue—such as a scent—with therapeutic material and re-exposing individuals to this cue during sleep to enhance long-term consolidation. Using this approach, we found that presenting during sleep the same scent previously associated with psychotherapy sessions triggered reactivation of therapy-related content, as reflected by increased neural signatures of memory reactivation in healthy participants. In patients with PTSD, re-exposure to the therapy-associated scent during sleep accelerated and strengthened the effects of imagery rescripting (Schaich et al., in preparation). We are now extending this approach to other clinical applications, including an ongoing study applying TMR to nightmare treatment using imagery rehearsal therapy (IRT) (Sayk et al., in preparation).
Circadian disruption and mental health
In many psychiatric disorders, circadian regulation is disrupted, and certain chronotypes appear to be at higher risk for developing such conditions. Within the newly established TRR 418 – Foundations of Circadian Medicine, we are investigating the mechanisms linking chronotype, circadian disruption, and depressive and trauma-related symptoms. We further plan to test interventions aimed at stabilizing circadian rhythms to improve existing symptoms and to prevent their onset or exacerbation.
Past research
Social Anxiety. Beyond trauma, we studied sleep-related mechanisms in social anxiety among children and adolescents. Our research shows that young people with social anxiety disorder exhibit markedly reduced spindle density, which is associated with heightened emotional reactivity to negative stimuli (Wilhelm et al., 2017). We also found that sleep-dependent memory consolidation is altered in socially anxious youth: unlike healthy controls, they preferentially extract negative information during sleep (Groch et al., 2017).