Amplitude changes of the N1 and the N1/P2 ERP component in response to different tone intensities have been suggested as a correlative of central serotonergic activity. A strong loudness dependence amplitude increase (strong intensity dependence) reflects low serotonergic neurotransmission and vice versa. Many researchers assumed that the brain serotonergic activity could influence treatment response of highly selective serotonin reuptake inhibitors in depression and anxiety disorders. There are a couple of studies reporting associations of N1 amplitude intensity dependence with response to Citalopram (positive correlation) and Reboxetine (negative correlation) treatment in major depressive disorder patients. But so far there have been no reports about associations between ERP N1 and antidepressant response in GAD patients.

So, it would be very interesting to explore the correlations between ERP N1 amplitude change and the Escitalopram treatment responsiveness in GAD patients.

• Linka T, Müller BW, Bender S, Sartory G, Gastpar M. The intensity dependence of auditory evoked ERP components predicts responsiveness to reboxetine treatment in major depression. Pharmacopsychiatry. 2005 May;38(3):139-43.
• Linka T, Sartory G, Bender S, Gastpar M, Müller BW. The intensity dependence of auditory ERP components in unmedicated patients with major depression and healthy controls. An analysis of group differences. J Affect Disord. 2007 Nov;103(1-3):139-45. Epub 2007 Feb 20.
• Linka T, Müller BW, Bender S, Sartory G. The intensity dependence of the auditory evoked N1 component as a predictor of response to Citalopram treatment in patients with major depression. Neurosci Lett. 2004 Sep 9;367(3):375-8.

Inclusion Criteria:

• DSM-IV TR for GAD
• Hamilton Rating Scale for Anxiety (HAMA) >18
• 18 to 65 years old

Exclusion Criteria:

• Severe medical illness
• Other psychiatric illness
• HAMD > 18
• High suicidal risk
• pregnancy