What is the Neuroscience-based Nomenclature (NbN) and how does it differ from DSM/ICD in terms of diagnosis, treatment planning, and billing?

Neuroscience-based Nomenclature (NbN): A Pharmacology-Driven Classification System

The Neuroscience-based Nomenclature (NbN) is a pharmacologically-driven classification system for psychotropic medications that categorizes drugs by their mechanism of action and pharmacological targets rather than by disease indication, fundamentally differing from DSM/ICD systems which remain categorical, symptom-based diagnostic frameworks used for diagnosis and billing. 1, 2

Core Concept and Purpose

• NbN classifies medications based on neuroscience and pharmacology—specifically the mechanism of action and pharmacological target—rather than the traditional disease-based nomenclature. 1
• The system was developed starting in 2009 to address misleading or confusing aspects of current psychotropic nomenclature, with a Child & Adolescent version (NbN C&A) released in 2018. 2
• NbN aims to assist in rational prescription, reduce stigma associated with disease-based drug names (like "antidepressants" or "antipsychotics"), and increase treatment adherence by focusing on what the drug does rather than what condition it treats. 1

Fundamental Differences from DSM/ICD

DSM/ICD Framework

• Both DSM-5 and ICD-11 remain categorical at their core, classifying mental phenomena based on self-reported or clinically observable symptoms rather than underlying pathophysiology or neurobiology. 3, 4
• Neither DSM nor ICD is based on neurobiology despite large biological heterogeneity within diagnostic categories and difficulties distinguishing categories genetically and neurobiologically. 3, 4
• These systems serve as diagnostic frameworks used for clinical diagnosis, treatment planning, research sample selection, and billing/coding purposes. 3

NbN Framework

• NbN is not a diagnostic system—it is exclusively a medication classification system that describes what drugs do pharmacologically, not what conditions patients have. 1, 2
• The system uses putative psychopharmacological mechanisms of action derived from preclinical and clinical studies to categorize medications. 2
• NbN presents the depth and richness of the neuroscience of psychotropics, making it valuable as both a prescribing tool and teaching resource. 5

Practical Implications for Clinical Use

For Diagnosis

• NbN does not replace or compete with DSM/ICD for diagnosis—clinicians still use DSM-5 or ICD-11 criteria to establish psychiatric diagnoses. 3, 4
• Structured diagnostic interviews (SCID-5 or MINI 7.0) remain the recommended approach for establishing diagnoses, not NbN. 4, 6

For Treatment Planning

• When selecting medications, NbN allows clinicians to think mechanistically about which pharmacological targets and mechanisms might address specific symptom domains rather than simply matching drug class to diagnostic category. 1, 2
• For treatment-resistant depression studies, different mechanisms of action (according to NbN) are explicitly recommended when defining adequate treatment trials. 3
• This mechanistic approach encourages scientifically-minded prescribing based on understanding what the drug does neurobiologically. 5

For Billing and Documentation

• Billing and insurance coding continue to require DSM-5 or ICD-11 diagnostic codes—NbN provides no billing codes and cannot be used for reimbursement purposes. 3
• Medical records and insurance claims must document diagnoses using the categorical disease entities from DSM/ICD systems. 3

Clinical Adoption and Endorsement

• NbN is currently endorsed by many psychiatric associations and has been adopted by several relevant journals as the preferred nomenclature for discussing psychotropic medications. 1
• The system is now included in major psychiatry textbooks, indicating growing acceptance in academic medicine. 1
• Educational studies demonstrate that introducing NbN to medical students during psychiatry clerkships resulted in significantly better understanding of psychopharmacology and increased interest in psychiatric residency compared to traditional teaching. 5

Integration with Existing Systems

• The optimal clinical approach uses DSM-5/ICD-11 for establishing categorical diagnoses (required for billing), then applies dimensional symptom assessments (as recommended in ICD-11), and finally uses NbN when selecting and discussing medications based on their mechanisms of action. 3, 4, 1
• ICD-11 has introduced dimensional symptom specifiers across six domains (positive symptoms, negative symptoms, depressive symptoms, manic symptoms, psychomotor symptoms, cognitive symptoms) rated on a 4-point scale, which can inform mechanistic medication selection using NbN. 4, 7
• This stepwise approach combines the clinical utility of categorical diagnosis (needed for communication and billing) with the precision of dimensional assessment and the scientific rigor of mechanism-based prescribing. 3, 4

Common Pitfalls to Avoid

• Do not attempt to use NbN as a diagnostic system or for billing purposes—it is exclusively for medication classification. 1, 2
• Avoid assuming that NbN replaces the need for understanding DSM/ICD diagnostic criteria, as these remain essential for clinical practice and research. 3
• Do not confuse "different mechanisms of action" (NbN concept) with "different drug classes" (traditional concept)—while these overlap, the pharmacological correspondence is not absolute, and NbN provides greater clarity. 3
• Recognize that NbN is a tool for rational prescribing and education, not a complete reconceptualization of psychiatric nosology like RDoC or other neurobiology-based diagnostic approaches. 3, 1