Code	Title
F01-F99	Mental, Behavioral and Neurodevelopmental disorders (F01-F99)
F50-F59	Behavioral syndromes associated with physiological disturbances and physical factors (F50-F59)
F51	Sleep disorders not due to a substance or known physiological condition Type 2 Excludes organic sleep disorders (G47.-)
F51.0	Insomnia not due to a substance or known physiological condition
F51.01	Primary insomnia
F51.02	Adjustment insomnia
F51.03	Paradoxical insomnia
F51.04	Psychophysiologic insomnia
F51.05	Insomnia due to other mental disorder
F51.09	Other insomnia not due to a substance or known physiological condition
F51.1	Hypersomnia not due to a substance or known physiological condition
F51.11	Primary hypersomnia
F51.12	Insufficient sleep syndrome
F51.13	Hypersomnia due to other mental disorder
F51.19	Other hypersomnia not due to a substance or known physiological condition
F51.3	Sleepwalking [somnambulism]
F51.4	Sleep terrors [night terrors]
F51.5	Nightmare disorder
F51.8	Other sleep disorders not due to a substance or known physiological condition
F51.9	Sleep disorder not due to a substance or known physiological condition, unspecified

F51 – Sleep disorders not due to a substance or known physiological condition