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.
If you have obstructive sleep apnea, your doctor may refer you to an ear, nose and throat doctor to rule out any blockage in your nose or throat. An evaluation by a heart doctor (cardiologist) or a doctor who specializes in the nervous system (neurologist) may be necessary to look for causes of central sleep apnea.