R46.2 Strange and inexplicable behavior

Billable ICD-10-CM code, FY2026.

Applies from R46 Symptoms and signs involving appearance and behavior

Excludes1 (never code together)

• appearance and behavior in schizophrenia, schizotypal and delusional disorders (F20-F29)
• mental and behavioral disorders (F01-F99)

MS-DRG index

Defines the logic of DRG(s) 951 in MDC 23.

Approximate ICD-9-CM (GEMs)

• 799.89 Other ill-defined conditions (approximate)

Diagnosis Index entries for R46.2

• Behavior › inexplicable
• Behavior › strange (and inexplicable)

Nearby codes

• R46 Symptoms and signs involving appearance and behavior
• R46.0 Very low level of personal hygiene
• R46.1 Bizarre personal appearance
• R46.2 Strange and inexplicable behavior (this code)
• R46.3 Overactivity
• R46.4 Slowness and poor responsiveness
• R46.5 Suspiciousness and marked evasiveness
• R46.6 Undue concern and preoccupation with stressful events
• R46.7 Verbosity and circumstantial detail obscuring reason for contact