Sleep problems and emotional and behavioral problems among adolescents: examining independent types, cumulative scores, and latent patterns.

Schizophrenia is a severe psychiatric disorder exhibiting considerable clinical heterogeneity. Affecting approximately 0.7% of the global population over a lifetime, it presents a considerable challenge to healthcare systems worldwide []. The etiology of schizophrenia arises from an intricate interplay between genetic predispositions and environmental influences. A core feature of schizophrenia is a disconnection from reality, manifesting primarily as positive symptoms, negative symptoms, and cognitive deficits. While current antipsychotic medications demonstrate considerable efficacy against positive symptoms, their effects on negative symptoms and cognitive impairment remain modest []. Nonetheless, negative symptoms represent a primary determinant of severe social dysfunction and unfavorable long-term prognosis, establishing them as a central therapeutic challenge and a critical priority in ongoing research. The negative symptoms of schizophrenia constitute a multidimensional construct. As outlined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and related consensus statements from the National Institute of Mental Health (NIMH), these symptoms encompass five specific manifestations: blunted affect, alogia, avolition, anhedonia, and asociality. Brian Kirkpatrick and colleagues introduced a two-dimensional theoretical model that groups these manifestations into two primary domains: “Motivation and Pleasure Deficit (MAP)” and “Emotional Expressivity Reduction (EXP).” This conceptual framework has been incorporated into contemporary assessment instruments such as the Brief Negative Symptom Scale (BNSS) and the Clinical Assessment Interview for Negative Symptoms (CAINS). Subsequent research has demonstrated that a hierarchical model based on this two-dimensional framework provides a superior fit to the data [], resulting in a closer alignment between theoretical constructs and empirical findings. This advancement has consequently enhanced the accuracy of both the assessment of negative symptoms and the investigation of their underlying mechanisms. Current therapeutics for negative symptoms remain limited. While neuromodulation techniques such as intermittent theta-burst stimulation (iTBS) [] and high-frequency repetitive transcranial magnetic stimulation (rTMS) [, ] have shown promising therapeutic potential, their widespread application is constrained by limitations including high costs, extended treatment duration, and substantial interindividual variability in treatment response. These factors collectively impose significant economic and psychological burdens on patients and their families. Consequently, there is a significant need to develop novel pharmacological interventions that are more accessible and cost-effective, representing an urgent research priority aimed at ameliorating negative symptoms and enhancing treatment accessibility.