| F51 | Sleep disorders not due to a substance or known physiological condition | NON-BILLABLE CODE |
| F51.0 | Insomnia not due to a substance or known physiological condition | NON-BILLABLE CODE |
| F51.01 | Primary insomnia | BILLABLE CODE |
| F51.02 | Adjustment insomnia | BILLABLE CODE |
| F51.03 | Paradoxical insomnia | BILLABLE CODE |
| F51.04 | Psychophysiologic insomnia | BILLABLE CODE |
| F51.05 | Insomnia due to other mental disorder | BILLABLE CODE |
| F51.1 | Hypersomnia not due to a substance or known physiological condition | NON-BILLABLE CODE |
| F51.11 | Primary hypersomnia | BILLABLE CODE |
| F51.12 | Insufficient sleep syndrome | BILLABLE CODE |
| F51.13 | Hypersomnia due to other mental disorder | BILLABLE CODE |
| F51.19 | Other hypersomnia not due to a substance or known physiological condition | BILLABLE CODE |
| F51.3 | Sleepwalking [somnambulism] | BILLABLE CODE |
| F51.4 | Sleep terrors [night terrors] | BILLABLE CODE |
| F51.5 | Nightmare disorder | BILLABLE CODE |
| F51.8 | Other sleep disorders not due to a substance or known physiological condition | BILLABLE CODE |
| F51.9 | Sleep disorder not due to a substance or known physiological condition, unspecified | BILLABLE CODE |
