ICD-10-CM 2027
ICD-10 code for Strange behavior
From the official ICD-10-CM alphabetic index entry “Behavior › strange (and inexplicable)”. Page updated September 29, 2026.
About coding Strange behavior
The ICD-10-CM code for Strange behavior is R46.2 (Strange and inexplicable behavior).
Within R46 (symptoms and signs involving appearance and behavior), R46.2 is specifically for Strange and inexplicable behavior. Related codes cover Very low level of personal hygiene (R46.0), Bizarre personal appearance (R46.1), overactivity (R46.3), Slowness and poor responsiveness (R46.4), Suspiciousness and marked evasiveness (R46.5), Undue concern and preoccupation with stressful events (R46.6), Verbosity and circumstantial detail obscuring reason for contact (R46.7) and other symptoms and signs involving appearance and behavior (R46.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 951 (Other Factors Influencing Health Status, relative weight 0.5577), in MDC 23 (Factors Influencing Health Status and Other Contacts with Health Services), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about Strange behavior ICD-10 codes
What is the ICD-10 code for Strange behavior?
- R46.2 — Strange and inexplicable behavior.
Is R46.2 billable?
- Yes. R46.2 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can R46.2 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict R46.2 as a principal diagnosis.
Is R46.2 a CC or MCC?
- No. R46.2 is neither a CC nor an MCC under MS-DRG v44.0.