Many causes exist and can include physical intrusions, psychological issues, chemical changes and side effects from medication, hormonal changes, or just poor habits. Frequently patients will say that they haven't slept well in years. The investigation must be thorough and include 24 hour histories of habits and activities.
Treatments can include sedating drugs in appropriate cases.
Most non-pharmacological treatments are described as behavioral. These range from biofeedback to aid relaxation to sleep restriction to condense sleep into sequential night time hours.