ICD-10-CM > F01-F99 > F50-F59 > F51 F51 Sleep disorders not due to a substance or known physiological condition Non-Billable/Non-Specific Type 2 Excludes organic sleep disorders (G47.-) Codes F51.0Insomnia not due to a substance or known physiological conditionF51.01Primary insomniaF51.02Adjustment insomniaF51.03Paradoxical insomniaF51.04Psychophysiologic insomniaF51.05Insomnia due to other mental disorderF51.09Other insomnia not due to a substance or known physiological conditionF51.1Hypersomnia not due to a substance or known physiological conditionF51.11Primary hypersomniaF51.12Insufficient sleep syndromeF51.13Hypersomnia due to other mental disorderF51.19Other hypersomnia not due to a substance or known physiological conditionF51.3Sleepwalking [somnambulism]F51.4Sleep terrors [night terrors]F51.5Nightmare disorderF51.8Other sleep disorders not due to a substance or known physiological conditionF51.9Sleep disorder not due to a substance or known physiological condition, unspecified