Prepulse inhibition deficits in GAD65 knockout mice and the effect of antipsychotic treatment.

Recent postmortem studies in humans suggest that defects in GABAergic neurotransmission might contribute to the neuropathology associated with schizophrenia. Disturbances in GABAergic systems may also contribute to the sensorimotor gating deficits classically observed in schizophrenic patients, including deficits in prepulse inhibition (PPI). To explore the relationship, the current study examined the integrity of PPI and startle habituation in knockout (KO) mice that lack the GABA synthesizing enzyme glutamic acid decarboxylase 65 (GAD 65). GAD65 KO mice displayed normal baseline and habituated startle responses, which did not differ from GAD65 wild-type (WT) or heterozygous (HET) mice. However, GAD65 KO mice showed robust deficits in PPI which were reversed by the atypical antipsychotic agent clozapine. These results lend support to the view that abnormalities in GABAergic systems might contribute to the basic pathophysiological mechanisms in schizophrenia.     

Prenatal fear of childbirth and anxiety sensitivity

Objective. Fear of childbirth (FOC) or what is historically referred to as tokophobia (a phobic state where a woman avoids childbirth despite desperately wanting a baby), is known to complicate the delivery process. In this study, the relationship of Anxiety Sensitivity (AS) to FOC was examined given that AS is a risk factor for other fears. Specifically, the contribution of three AS dimensions (physical, psychological or social concerns) relative to other factors (e.g., parity of the mother, trait anxiety) in accounting for FOC was explored.

Methods. Women in their final 4 months of pregnancy (n = 110) completed the Anxiety Sensitivity Index, the State-Trait Anxiety Inventory-Trait Scale and the Wijma Delivery Expectancy/Experience Questionnaire.

Results. Most demographic variables were non-significant in predicting FOC with the exception of participants' parity. Multiple regression analysis revealed that AS-physical concerns significantly predicted elevated FOC even after controlling for parity and trait anxiety; higher levels of AS-physical concerns, higher trait anxiety, and expecting a first child all independently predicted greater FOC.

Conclusion. Variance in FOC is explained, in part, by AS-physical concerns. Further, AS-physical concerns are distinct from trait anxiety in predicting FOC. Similar to other fears, the results support the possibility that AS may be a risk factor for elevated FOC.