| G40 | Epilepsy and recurrent seizures |
| G40.0 | Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset |
| G40.00 | Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, not intractable |
| G40.001 | Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, not intractable, with status epilepticus |
| G40.009 | Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, not intractable, without status epilepticus |
| G40.01 | Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, intractable |
| G40.011 | Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, intractable, with status epilepticus |
| G40.019 | Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, intractable, without status epilepticus |
| G40.1 | Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures |
| G40.10 | Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, not intractable |
| G40.101 | Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, not intractable, with status epilepticus |
| G40.109 | Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, not intractable, without status epilepticus |
| G40.11 | Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, intractable |
| G40.111 | Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, intractable, with status epilepticus |
| G40.119 | Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, intractable, without status epilepticus |
| G40.2 | Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures |
| G40.20 | Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, not intractable |
| G40.201 | Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, not intractable, with status epilepticus |
| G40.209 | Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, not intractable, without status epilepticus |
| G40.21 | Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, intractable |
| G40.211 | Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, intractable, with status epilepticus |
| G40.219 | Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, intractable, without status epilepticus |
| G40.3 | Generalized idiopathic epilepsy and epileptic syndromes |
| G40.30 | Generalized idiopathic epilepsy and epileptic syndromes, not intractable |
| G40.301 | Generalized idiopathic epilepsy and epileptic syndromes, not intractable, with status epilepticus |
| G40.309 | Generalized idiopathic epilepsy and epileptic syndromes, not intractable, without status epilepticus |
| G40.31 | Generalized idiopathic epilepsy and epileptic syndromes, intractable |
| G40.311 | Generalized idiopathic epilepsy and epileptic syndromes, intractable, with status epilepticus |
| G40.319 | Generalized idiopathic epilepsy and epileptic syndromes, intractable, without status epilepticus |
| G40.A | Absence epileptic syndrome |
| G40.A0 | Absence epileptic syndrome, not intractable |
| G40.A01 | Absence epileptic syndrome, not intractable, with status epilepticus |
| G40.A09 | Absence epileptic syndrome, not intractable, without status epilepticus |
| G40.A1 | Absence epileptic syndrome, intractable |
| G40.A11 | Absence epileptic syndrome, intractable, with status epilepticus |
| G40.A19 | Absence epileptic syndrome, intractable, without status epilepticus |
| G40.B | Juvenile myoclonic epilepsy [impulsive petit mal] |
| G40.B0 | Juvenile myoclonic epilepsy, not intractable |
| G40.B01 | Juvenile myoclonic epilepsy, not intractable, with status epilepticus |
| G40.B09 | Juvenile myoclonic epilepsy, not intractable, without status epilepticus |
| G40.B1 | Juvenile myoclonic epilepsy, intractable |
| G40.B11 | Juvenile myoclonic epilepsy, intractable, with status epilepticus |
| G40.B19 | Juvenile myoclonic epilepsy, intractable, without status epilepticus |
| G40.4 | Other generalized epilepsy and epileptic syndromes |
| G40.40 | Other generalized epilepsy and epileptic syndromes, not intractable |
| G40.401 | Other generalized epilepsy and epileptic syndromes, not intractable, with status epilepticus |
| G40.409 | Other generalized epilepsy and epileptic syndromes, not intractable, without status epilepticus |
| G40.41 | Other generalized epilepsy and epileptic syndromes, intractable |
| G40.411 | Other generalized epilepsy and epileptic syndromes, intractable, with status epilepticus |
| G40.419 | Other generalized epilepsy and epileptic syndromes, intractable, without status epilepticus |
| G40.5 | Epileptic seizures related to external causes |
| G40.50 | Epileptic seizures related to external causes, not intractable |
| G40.501 | Epileptic seizures related to external causes, not intractable, with status epilepticus |
| G40.509 | Epileptic seizures related to external causes, not intractable, without status epilepticus |
| G40.8 | Other epilepsy and recurrent seizures |
| G40.80 | Other epilepsy |
| G40.801 | Other epilepsy, not intractable, with status epilepticus |
| G40.802 | Other epilepsy, not intractable, without status epilepticus |
| G40.803 | Other epilepsy, intractable, with status epilepticus |
| G40.804 | Other epilepsy, intractable, without status epilepticus |
| G40.81 | Lennox-Gastaut syndrome |
| G40.811 | Lennox-Gastaut syndrome, not intractable, with status epilepticus |
| G40.812 | Lennox-Gastaut syndrome, not intractable, without status epilepticus |
| G40.813 | Lennox-Gastaut syndrome, intractable, with status epilepticus |
| G40.814 | Lennox-Gastaut syndrome, intractable, without status epilepticus |
| G40.82 | Epileptic spasms |
| G40.821 | Epileptic spasms, not intractable, with status epilepticus |
| G40.822 | Epileptic spasms, not intractable, without status epilepticus |
| G40.823 | Epileptic spasms, intractable, with status epilepticus |
| G40.824 | Epileptic spasms, intractable, without status epilepticus |
| G40.89 | Other seizures |
| G40.9 | Epilepsy, unspecified |
| G40.90 | Epilepsy, unspecified, not intractable |
| G40.901 | Epilepsy, unspecified, not intractable, with status epilepticus |
| G40.909 | Epilepsy, unspecified, not intractable, without status epilepticus |
| G40.91 | Epilepsy, unspecified, intractable |
| G40.911 | Epilepsy, unspecified, intractable, with status epilepticus |
| G40.919 | Epilepsy, unspecified, intractable, without status epilepticus |
| G43 | Migraine |
| G43.0 | Migraine without aura |
| G43.00 | Migraine without aura, not intractable |
| G43.001 | Migraine without aura, not intractable, with status migrainosus |
| G43.009 | Migraine without aura, not intractable, without status migrainosus |
| G43.01 | Migraine without aura, intractable |
| G43.011 | Migraine without aura, intractable, with status migrainosus |
| G43.019 | Migraine without aura, intractable, without status migrainosus |
| G43.1 | Migraine with aura |
| G43.10 | Migraine with aura, not intractable |
| G43.101 | Migraine with aura, not intractable, with status migrainosus |
| G43.109 | Migraine with aura, not intractable, without status migrainosus |
| G43.11 | Migraine with aura, intractable |
| G43.111 | Migraine with aura, intractable, with status migrainosus |
| G43.119 | Migraine with aura, intractable, without status migrainosus |
| G43.4 | Hemiplegic migraine |
| G43.40 | Hemiplegic migraine, not intractable |
| G43.401 | Hemiplegic migraine, not intractable, with status migrainosus |
| G43.409 | Hemiplegic migraine, not intractable, without status migrainosus |
| G43.41 | Hemiplegic migraine, intractable |
| G43.411 | Hemiplegic migraine, intractable, with status migrainosus |
| G43.419 | Hemiplegic migraine, intractable, without status migrainosus |
| G43.5 | Persistent migraine aura without cerebral infarction |
| G43.50 | Persistent migraine aura without cerebral infarction, not intractable |
| G43.501 | Persistent migraine aura without cerebral infarction, not intractable, with status migrainosus |
| G43.509 | Persistent migraine aura without cerebral infarction, not intractable, without status migrainosus |
| G43.51 | Persistent migraine aura without cerebral infarction, intractable |
| G43.511 | Persistent migraine aura without cerebral infarction, intractable, with status migrainosus |
| G43.519 | Persistent migraine aura without cerebral infarction, intractable, without status migrainosus |
| G43.6 | Persistent migraine aura with cerebral infarction |
| G43.60 | Persistent migraine aura with cerebral infarction, not intractable |
| G43.601 | Persistent migraine aura with cerebral infarction, not intractable, with status migrainosus |
| G43.609 | Persistent migraine aura with cerebral infarction, not intractable, without status migrainosus |
| G43.61 | Persistent migraine aura with cerebral infarction, intractable |
| G43.611 | Persistent migraine aura with cerebral infarction, intractable, with status migrainosus |
| G43.619 | Persistent migraine aura with cerebral infarction, intractable, without status migrainosus |
| G43.7 | Chronic migraine without aura |
| G43.70 | Chronic migraine without aura, not intractable |
| G43.701 | Chronic migraine without aura, not intractable, with status migrainosus |
| G43.709 | Chronic migraine without aura, not intractable, without status migrainosus |
| G43.71 | Chronic migraine without aura, intractable |
| G43.711 | Chronic migraine without aura, intractable, with status migrainosus |
| G43.719 | Chronic migraine without aura, intractable, without status migrainosus |
| G43.A | Cyclical vomiting |
| G43.A0 | Cyclical vomiting, not intractable |
| G43.A1 | Cyclical vomiting, intractable |
| G43.B | Ophthalmoplegic migraine |
| G43.B0 | Ophthalmoplegic migraine, not intractable |
| G43.B1 | Ophthalmoplegic migraine, intractable |
| G43.C | Periodic headache syndromes in child or adult |
| G43.C0 | Periodic headache syndromes in child or adult, not intractable |
| G43.C1 | Periodic headache syndromes in child or adult, intractable |
| G43.D | Abdominal migraine |
| G43.D0 | Abdominal migraine, not intractable |
| G43.D1 | Abdominal migraine, intractable |
| G43.8 | Other migraine |
| G43.80 | Other migraine, not intractable |
| G43.801 | Other migraine, not intractable, with status migrainosus |
| G43.809 | Other migraine, not intractable, without status migrainosus |
| G43.81 | Other migraine, intractable |
| G43.811 | Other migraine, intractable, with status migrainosus |
| G43.819 | Other migraine, intractable, without status migrainosus |
| G43.82 | Menstrual migraine, not intractable |
| G43.821 | Menstrual migraine, not intractable, with status migrainosus |
| G43.829 | Menstrual migraine, not intractable, without status migrainosus |
| G43.83 | Menstrual migraine, intractable |
| G43.831 | Menstrual migraine, intractable, with status migrainosus |
| G43.839 | Menstrual migraine, intractable, without status migrainosus |
| G43.9 | Migraine, unspecified |
| G43.90 | Migraine, unspecified, not intractable |
| G43.901 | Migraine, unspecified, not intractable, with status migrainosus |
| G43.909 | Migraine, unspecified, not intractable, without status migrainosus |
| G43.91 | Migraine, unspecified, intractable |
| G43.911 | Migraine, unspecified, intractable, with status migrainosus |
| G43.919 | Migraine, unspecified, intractable, without status migrainosus |
| G44 | Other headache syndromes |
| G44.0 | Cluster headaches and other trigeminal autonomic cephalgias (TAC) |
| G44.00 | Cluster headache syndrome, unspecified |
| G44.001 | Cluster headache syndrome, unspecified, intractable |
| G44.009 | Cluster headache syndrome, unspecified, not intractable |
| G44.01 | Episodic cluster headache |
| G44.011 | Episodic cluster headache, intractable |
| G44.019 | Episodic cluster headache, not intractable |
| G44.02 | Chronic cluster headache |
| G44.021 | Chronic cluster headache, intractable |
| G44.029 | Chronic cluster headache, not intractable |
| G44.03 | Episodic paroxysmal hemicrania |
| G44.031 | Episodic paroxysmal hemicrania, intractable |
| G44.039 | Episodic paroxysmal hemicrania, not intractable |
| G44.04 | Chronic paroxysmal hemicrania |
| G44.041 | Chronic paroxysmal hemicrania, intractable |
| G44.049 | Chronic paroxysmal hemicrania, not intractable |
| G44.05 | Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) |
| G44.051 | Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), intractable |
| G44.059 | Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), not intractable |
| G44.09 | Other trigeminal autonomic cephalgias (TAC) |
| G44.091 | Other trigeminal autonomic cephalgias (TAC), intractable |
| G44.099 | Other trigeminal autonomic cephalgias (TAC), not intractable |
| G44.1 | Vascular headache, not elsewhere classified |
| G44.2 | Tension-type headache |
| G44.20 | Tension-type headache, unspecified |
| G44.201 | Tension-type headache, unspecified, intractable |
| G44.209 | Tension-type headache, unspecified, not intractable |
| G44.21 | Episodic tension-type headache |
| G44.211 | Episodic tension-type headache, intractable |
| G44.219 | Episodic tension-type headache, not intractable |
| G44.22 | Chronic tension-type headache |
| G44.221 | Chronic tension-type headache, intractable |
| G44.229 | Chronic tension-type headache, not intractable |
| G44.3 | Post-traumatic headache |
| G44.30 | Post-traumatic headache, unspecified |
| G44.301 | Post-traumatic headache, unspecified, intractable |
| G44.309 | Post-traumatic headache, unspecified, not intractable |
| G44.31 | Acute post-traumatic headache |
| G44.311 | Acute post-traumatic headache, intractable |
| G44.319 | Acute post-traumatic headache, not intractable |
| G44.32 | Chronic post-traumatic headache |
| G44.321 | Chronic post-traumatic headache, intractable |
| G44.329 | Chronic post-traumatic headache, not intractable |
| G44.4 | Drug-induced headache, not elsewhere classified |
| G44.40 | Drug-induced headache, not elsewhere classified, not intractable |
| G44.41 | Drug-induced headache, not elsewhere classified, intractable |
| G44.5 | Complicated headache syndromes |
| G44.51 | Hemicrania continua |
| G44.52 | New daily persistent headache (NDPH) |
| G44.53 | Primary thunderclap headache |
| G44.59 | Other complicated headache syndrome |
| G44.8 | Other specified headache syndromes |
| G44.81 | Hypnic headache |
| G44.82 | Headache associated with sexual activity |
| G44.83 | Primary cough headache |
| G44.84 | Primary exertional headache |
| G44.85 | Primary stabbing headache |
| G44.89 | Other headache syndrome |
| G45 | Transient cerebral ischemic attacks and related syndromes |
| G45.0 | Vertebro-basilar artery syndrome |
| G45.1 | Carotid artery syndrome (hemispheric) |
| G45.2 | Multiple and bilateral precerebral artery syndromes |
| G45.3 | Amaurosis fugax |
| G45.4 | Transient global amnesia |
| G45.8 | Other transient cerebral ischemic attacks and related syndromes |
| G45.9 | Transient cerebral ischemic attack, unspecified |
| G46 | Vascular syndromes of brain in cerebrovascular diseases |
| G46.0 | Middle cerebral artery syndrome |
| G46.1 | Anterior cerebral artery syndrome |
| G46.2 | Posterior cerebral artery syndrome |
| G46.3 | Brain stem stroke syndrome |
| G46.4 | Cerebellar stroke syndrome |
| G46.5 | Pure motor lacunar syndrome |
| G46.6 | Pure sensory lacunar syndrome |
| G46.7 | Other lacunar syndromes |
| G46.8 | Other vascular syndromes of brain in cerebrovascular diseases |
| G47 | Sleep disorders |
| G47.0 | Insomnia |
| G47.00 | Insomnia, unspecified |
| G47.01 | Insomnia due to medical condition |
| G47.09 | Other insomnia |
| G47.1 | Hypersomnia |
| G47.10 | Hypersomnia, unspecified |
| G47.11 | Idiopathic hypersomnia with long sleep time |
| G47.12 | Idiopathic hypersomnia without long sleep time |
| G47.13 | Recurrent hypersomnia |
| G47.14 | Hypersomnia due to medical condition |
| G47.19 | Other hypersomnia |
| G47.2 | Circadian rhythm sleep disorders |
| G47.20 | Circadian rhythm sleep disorder, unspecified type |
| G47.21 | Circadian rhythm sleep disorder, delayed sleep phase type |
| G47.22 | Circadian rhythm sleep disorder, advanced sleep phase type |
| G47.23 | Circadian rhythm sleep disorder, irregular sleep wake type |
| G47.24 | Circadian rhythm sleep disorder, free running type |
| G47.25 | Circadian rhythm sleep disorder, jet lag type |
| G47.26 | Circadian rhythm sleep disorder, shift work type |
| G47.27 | Circadian rhythm sleep disorder in conditions classified elsewhere |
| G47.29 | Other circadian rhythm sleep disorder |
| G47.3 | Sleep apnea |
| G47.30 | Sleep apnea, unspecified |
| G47.31 | Primary central sleep apnea |
| G47.32 | High altitude periodic breathing |
| G47.33 | Obstructive sleep apnea (adult) (pediatric) |
| G47.34 | Idiopathic sleep related nonobstructive alveolar hypoventilation |
| G47.35 | Congenital central alveolar hypoventilation syndrome |
| G47.36 | Sleep related hypoventilation in conditions classified elsewhere |
| G47.37 | Central sleep apnea in conditions classified elsewhere |
| G47.39 | Other sleep apnea |
| G47.4 | Narcolepsy and cataplexy |
| G47.41 | Narcolepsy |
| G47.411 | Narcolepsy with cataplexy |
| G47.419 | Narcolepsy without cataplexy |
| G47.42 | Narcolepsy in conditions classified elsewhere |
| G47.421 | Narcolepsy in conditions classified elsewhere with cataplexy |
| G47.429 | Narcolepsy in conditions classified elsewhere without cataplexy |
| G47.5 | Parasomnia |
| G47.50 | Parasomnia, unspecified |
| G47.51 | Confusional arousals |
| G47.52 | REM sleep behavior disorder |
| G47.53 | Recurrent isolated sleep paralysis |
| G47.54 | Parasomnia in conditions classified elsewhere |
| G47.59 | Other parasomnia |
| G47.6 | Sleep related movement disorders |
| G47.61 | Periodic limb movement disorder |
| G47.62 | Sleep related leg cramps |
| G47.63 | Sleep related bruxism |
| G47.69 | Other sleep related movement disorders |
| G47.8 | Other sleep disorders |
| G47.9 | Sleep disorder, unspecified |