Heavy cannabis use (HCU) is linked to changes in both brain structure and function, even in individuals without a cannabis-use disorder or other major mental illnesses. This study used multimodal MRI to examine grey matter volume and intrinsic neural activity in 24 heavy users and 16 controls. Two distinct brain component patterns differed between groups: one involving the cerebellum, temporal, and thalamic regions (structural), and another involving frontal and parietal regions (functional). These patterns correlated with specific cannabis-use behaviors. Additionally, the structural changes were associated with the serotonergic system, while functional changes were linked to serotonergic, dopaminergic, and μ-opioid receptor systems, offering new insights into the neural mechanisms of heavy cannabis use.
Altered experiences of time and space are linked to general symptoms and basic self-disorders in people with schizophrenia spectrum disorder. Self-disturbance acts as a key mediator through which fundamental time-space disruptions influence perceptual changes as well as negative, positive, and general symptoms. Data were collected at three medical expert centers using semi-structured phenomenological interviews and analyzed with network and mediation methods.
Patients with schizophrenia often experience fragmented time and distorted spatial perception, such as abnormal interpersonal distance and orientation, which can detach them from reality and complicate therapy. Despite this, these experiences remain understudied due to a lack of standardized measurement tools. Based on spatiotemporal psychopathology (STPP), a clinical rating scale called the Scale for Space and Time Experience in Psychosis (STEP) was developed. The German version of STEP assesses 14 spatial and 11 temporal phenomena across 25 items. It demonstrates high internal consistency (Cronbach's alpha = 0.94) and significant correlation with the Positive and Negative Syndrome Scale (PANSS; p < 0.001), offering a valuable instrument for German-speaking countries.
Catatonia involves complex symptoms that combine motor, affective, and behavioral phenomena and occurs across multiple psychiatric diagnoses, revealing the limits of current affective and cognitive psychopathological approaches. Spatiotemporal Psychopathology (STPP) is developed further here, based on recent clinical and neuroscience findings. STPP has two core features: an experience-based approach that accounts for symptoms through first-person experience of time-space, and an integrated brain-mind approach where the brain's neural topography and dynamic (inner time and space) are shared with the mind's mental topography and dynamic (time-space experience) as their common currency. These features account for catatonia's symptom complexity and trans-diagnostic nature, making it a paradigmatic example for a more comprehensive psychopathological approach.