The nonrapid eye movement parasomnias: recent advances and forensic aspects.

PURPOSE OF REVIEW: The aim is to update the readership on recent advances in the diagnosis and classification of nonrapid eye movement (NREM) sleep parasomnias with an emphasis on recent research findings and related forensic consequences of the parasomnias.

RECENT FINDINGS: The Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) has further refined the classification and diagnostic criteria for the parasomnias, dividing them into non-REM and REM sleep disorders. It has removed confusional arousal disorder and updated the diagnostic criteria in keeping with the evidence-base available at the time of its final drafting. New research subsequent to the final drafting of the DSM-5 has clarified certain aspects including those related to the risk factors ('triggers') for sleepwalking and the impact of sleepwalking on daytime functioning, social and occupational functioning. These new research data should be considered in the development of the next International Classification of Sleep Disorders. The new diagnostic system and research data provide further clarity for the forensic sleep medicine practitioner.

SUMMARY: The DSM-5 diagnostic criteria combined with the latest research will inform both clinical and forensic sleep medicine practice and provide further impetus for evidence-based practice.