In the primary repression phase, 'it is highly probable that the immediate precipitating causes of primal repressions are quantitative factors such as...the earliest outbreaks of anxiety, which are of a very intense kind'.
1 A neurologist treats brain and nervous system disorders that may contribute to sleep problems.  An otolaryngologist treats ear, nose, and throat conditions. This doctor may evaluate snoring and other breathing problems associated with sleep disorders.
Psychologists and psychiatrists can help treat some cases of insomnia. A psychologist is a social scientist who has studied behavior and mental processes. A psychiatrist is a physician who specializes in the diagnosis and treatment of mental disorders.