Also, here's a list of diagnoses that are related to sleep disorders. Just to help give you a list of things to research, and a vocabulary to work with.
Adjustment Insomnia
Advanced Sleep Phase
Bedwetting
Behavioral Insomnia of Childhood
Central Sleep Apnea
Circadian Rhythm Sleep Disorder
Congenital Central Alveolar Hypoventilation Syndrome
Delayed Sleep Phase
Dissociative Disorders
Eating Disorder
Environmental Sleep Disorder
Excessive Fragmentary Myoclonus
Exploding Head Syndrome
Free-Running (Nonentrained) Type
Grinding Teeth (Bruxism)
Groaning
Hallucinations
Hypersomnia Due to Drug or Substance
Hypersomnia Due to Medical Condition
Hypoventilation/Hypoxemia Due to Lower Airways Obstruction
Hypoventilation/Hypoxemia Due to Neuromuscular and Chest Wall Disorders
Hypoventilation/Hypoxemia Due to Pulmonary Parenchymal or Vascular Pathology
Idiopathic Hypersomnia with Long Sleep Time
Idiopathic Hypersomnia without Long Sleep Time
Idiopathic Insomnia
Insomnia Due to Drug or Substance
Insomnia Due to Medical Condition
Insomnia Due to Mental Disorder
Insomnia Nonorganic, Unspecified
Insomnia Organic, Unspecified
Insufficient Sleep Syndrome
Irregular Sleep-Wake Rhythm
Leg Cramps
Long Sleeper
Movement Disorder Due to Drug or Substance
Movement Disorder Due to Medical Condition
Movement Disorder, Unspecified
Narcolepsy Due to Medical Condition
Narcolepsy, Unspecified
Nightmares
Non-Obstructive Alveolar Hypoventilation, Idiopathic
Obstructive Sleep Apnea in Children
Paradoxical Insomnia
Parasomnia Due to Drug, Substance or Medical Condition
Primary Sleep Apnea of Infancy
Propriospinal Myoclonus of Sleep Onset
Psychophysiological Insomnia
Recurrent Hypersomnia
REM Sleep Behavior Disorder
Rhythmic Movement
Short Sleeper
Sleep Apnea/Sleep Related Breathing Disorder, Unspecified
Sleep Paralysis
Sleep Starts
Sleep Talking
Snoring