
    recruiting problems because of the time expenditure required for participating and the strict
    criteria of inclusion and exclusion
  
['insomnia']
['amitriptyline', 'zolpidem', 'amitriptyline', 'placebo']

        Inclusion Criteria:

          1. age between 18 years to 69 years

          2. fluent in German language

          3. provide written informed consent

          4. ability to understand the explanations and instructions given by the study physician
             and the investigator

        Exclusion Criteria:

          1. Sleep disorders caused by medical factors (e.g. sleep apnea, restless legs syndrome,
             narcolepsy, substance-induced insomnia)

          2. Contraindications to study medication intake according to the information sheet for
             health professionals (Summary of medicinal Product Characteristics, SmPC;
             Fachinformation in Germany) assessed by physical examination (including ECG) and
             medical history

               -  allergies to amitriptyline hydrochloride or any of its ingredients

               -  allergies to zolpidem or any of its ingredients

               -  acute intoxication with alcohol, analgetics, hypnotics or any other psychotropic
                  drug

               -  urinary retention

               -  delirium

               -  untreated closed-angle glaucoma

               -  prostatic hyperplasia

               -  pyloric stenosis

               -  paralytic ilius

               -  suicidal thoughts

               -  liver/ kidney/ pulmonary insufficiency

               -  myasthenia gravis

               -  hypokalemia

               -  bradycardia

               -  coronary heart disease, cardiac arrhythmias, long QT syndrome or other clinically
                  relevant cardiac disorders

               -  increased risk of seizures/ history of seizures

               -  substance dependence syndrome/ history of substance dependence syndrome

          3. Allergies to ingredients of placebo or novel-tasting drink (CS)

          4. currently pregnant (verified by urine pregnancy test) or lactating

          5. patients scoring ≥12 on the Epworth Sleepiness Scale

          6. patients scoring below 8 or above 21 on the Insomnia Severity Index

          7. patients suffering from a mental disorder as verified by the SCID (major depression;
             psychosis; brain injury; substance abuse or dependency syndrome during the last 6
             months before V1)

          8. nicotine consumption > 10 cigarettes/day

          9. unwillingness to refrain from alcohol consumption throughout the study

         10. Concomitant medication interfering with study medication intake due to potential
             interactions (all psychotropic medication including analgetics and muscle relaxants,
             hypericum derivatives; antihypertensives; anti-arrhythmic agents; antibiotics;
             cisaprid; anti-malaria drugs; diuretics; imidazole antifungals; cumarin derivatives;
             antihistaminics; calcium channel blockers; medications that enlarge the QT interval or
             may lead to hypokalemia)

         11. change in concomitant medication regime during the last 2 weeks prior to visit 1 or
             after randomization

         12. intake of psychotropic medication during the last 3 months

         13. participation in any other clinical trial 3 months prior to visit 1

         14. women of childbearing age not using 2 highly effective contraceptive methods

         15. employee of the Sponsor or the principal investigator
      