Theta States (2017) on Netflix

Plot summary

Danny has struggled with insomnia for years, so he responds to an advertisement for the Audible Lucid Perceptions sleep clinic and sits down with Dr. Zovnig. The doctor hands him a small audio player that produces sound waves tuned to alter brain frequencies and lull him into a dream state. After the first session Danny sleeps better than he can ever remember sleeping. Then nightmares fill his nights, waking visions trouble him during the day, and he loses stretches of time while he is awake. He cannot tell whether the treatment is responsible or whether something else has taken an interest in him.