How Robust is the Influence of Causal Explanation on Clinical Judgments? Assessments in Structured Clinical Interviews.

When causal life-event explanations for disorder symptoms are available, clinicians tend to explain away those symptoms (Ahn, Novick, & Kim, 2003 ; Meehl, 1973 ), eschewing formal diagnostic guidelines such as the DSM-5 (American Psychiatric Association, 2013 ). We asked whether this effect is attenuated in the context of a structured diagnostic clinical interview procedure, which deliberately directs evaluators' attention to symptoms alone, or whether it is robust enough to continue to emerge. Across two experiments, lay evaluators given causal life-event explanations for disordered behaviors gave them lower judgments of abnormality and need for treatment compared to evaluators not given such explanations, regardless of whether they used a structured clinical interview. Thus, causal life-event explanations may have significant impact on clinical evaluations regardless of the mode of assessment. Implications for the clinical utility of structured interviews and the role of life-event context in diagnosis and classification are discussed.

Meclizine enhancement of sensorimotor gating in healthy male subjects with high startle responses and low prepulse inhibition.

Histamine H1 receptor systems have been shown in animal studies to have important roles in the reversal of sensorimotor gating deficits, as measured by prepulse inhibition (PPI). H1-antagonist treatment attenuates the PPI impairments caused by either blockade of NMDA glutamate receptors or facilitation of dopamine transmission. The current experiment brought the investigation of H1 effects on sensorimotor gating to human studies. The effects of the histamine H1 antagonist meclizine on the startle response and PPI were investigated in healthy male subjects with high baseline startle responses and low PPI levels. Meclizine was administered to participants (n=24) using a within-subjects design with each participant receiving 0, 12.5, and 25 mg of meclizine in a counterbalanced order. Startle response, PPI, heart rate response, galvanic skin response, and changes in self-report ratings of alertness levels and affective states (arousal and valence) were assessed. When compared with the control (placebo) condition, the two doses of meclizine analyzed (12.5 and 25 mg) produced significant increases in PPI without affecting the magnitude of the startle response or other physiological variables. Meclizine also caused a significant increase in overall self-reported arousal levels, which was not correlated with the observed increase in PPI. These results are in agreement with previous reports in the animal literature and suggest that H1 antagonists may have beneficial effects in the treatment of subjects with compromised sensorimotor gating and enhanced motor responses to sensory stimuli.