The purpose of this study is to further explore an effective dose range of PD0200390 for the treatment of patients with insomnia.

Inclusion Criteria:

3 month history of Primary Insomnia (DSM-IV criteria)

Self report sleep criteria for at least 3 nights per week in past month;

sWASO (subjective wake after sleep onset) equal or greater than 60 mins

sLSO (subjective latency to sleep onset) equal or greater than 45 minutes

TST less than or equal to 6.5 hrs

Maintain normal daytime-awake, nighttime-sleep schedule

PSG sleep criteria of mean WASO equal or greater than 60 mins calculated on 2 PSG screening nights

TST between 3 to 7 hrs on 2 PSG screening nights

Mean LPS (latency to persistent sleep) equal or greater than 20 mins calculated on 2 PSG screening nights

Exclusion Criteria:

Comorbid psychiatric disease or disorders

History or presence of breathing-related disorders

Multivariable Apnea risk index (MAP) equal or greater than 0.5 at screening

History or presence of medical or neurological condition interfering with sleep

Current use of know psychotropic effect medications

Excessive caffeine use

Use of alcohol as a sleep aid or more than 2 standard drinks/day