A Randomized, Placebo-Controlled Study to Evaluate the Efficacy and Tolerability of Asenapine With Flexible Dosing From 5mg to 20mg in Adults With Developmental Stuttering

Inclusion Criteria: Subjects can be enrolled in the study only if they meet all of the following criteria: 1. Subjects must satisfy DSM-IV criteria for stuttering. 2. The nature of stuttering must be developmental in origin with the onset prior to ten years of age. 3. Subjects must have a score of moderate or higher on the SSI-IV. 4) Women of child-bearing potential are eligible to participate as long as they are practicing a medically accepted form of contraception (i.e. condom with spermicide or diaphragm, oral or depot contraception, or an intrauterine device). 5)Subjects will be male or female from the ages of 18-70. 6)Subjects will be of only English speaking. Exclusion Criteria: Subjects will be excluded from the study for any of the following reasons: 1. Stuttering related to a known neurologic cause (e.g. head trauma, stroke). 2. Unstable medical or psychiatric illness. 3. Active substance abuse within three months prior to study inclusion. 4. Any illness that would require the concomitant use of a CNS active medication during the course of the study. 5. Subjects with Parkinson's dementia or other degenerative neurologic illness. 6. Subjects who are pregnant or nursing an infant. 7. No minors (under the age of 18) will not be enrolled in this study as the research with this compound in children and adolescents has not been fully performed. 8. Subjects who suffer from seizures, irregular heartbeat or an elevated blood sugar level (glucose).