Efficacy an Safety of Volinanserin on Sleep Maintenance Insomnia With a Sub-study on Stable Type II Diabetes Mellitus

Inclusion Criteria: * Diagnosis of primary insomnia based on Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) criteria * Disturbances of sleep maintenance criteria based on participant's information related to sleep pattern during the preceding month Sub-study : * Participants will be included if they have an established medical diagnosis of type II Diabetes Mellitus, and have been treated either with an oral hypoglycemic agent and/or insulin for at least three months prior to the Screening Visit (with stable regimen for at least one month prior to screening) Exclusion Criteria: * Females who are lactating or who are pregnant * Night shift workers, and individuals who nap 3 or more times per week over the preceding month * Consumption of xanthine-containing beverages (i.e. tea, coffee, cola) comprising more than 5 cups/day * Participation in another trial having received study medication within 1 month before the screening visit * Body Mass Index ≥ 33 * Use of over-the-counter medications such as tryptophan, valerian root, kava, melatonin, St. John's Wort, Alluna or prescription sleep medication * Use of any substance with psychotropic effects or properties know to affect sleep/wake * History of primary hypersomnia, narcolepsy, breathing-related sleep disorder, circadian rhythm sleep disorder, parasomnia, dyssomnia * Clinically significant, severe or unstable, acute or chronically progressive medical or surgical disorder * Positive qualitative urine drug screen (opiates, cocaine, amphetamine…) The above information is not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.