Serotonin, Serotonin Genetics(TPH2) and Emotion and Interference Processing

The Influence of Acute Tryptophan Depletion on Emotion and Interference Processing and Potential Moderation by 5HT Genetics (TPH2)

The study aims to explore whether acute tryptophan depletion can affect the emotion and interference processing whether this effect is moderated by the TPH2 genotype

Based on previous studies suggesting that serotonin, a neurotransmitter, is associated with social & emotional behavior, including emotional reactivity and emotion regulation, the present study aims to explore effects of acute tryptophan depletion (ATD) on emotion processing and emotional interference processing within a randomized double-blind, with-subject, placebo-controlled pharmaco-fMRI experiment. To further examine the potential moderating effects of the genetic makeup of the serotonin system the present study will include a pharmacogenetics imaging approach. Given that TPH2 is the key regulator of the serotonergic signaling pathway, we therefore assessed whether such the effects of tryptophan depletion vary according to the TPH2 genotype. To this end, healthy male TPH2-GG or TPH2-TT carriers will be recruited and will receive ATD (100g) and placebo (102.3g) in a within subject design. To control for potential effects of pre-medication personality traits as well as effects of medicines on mood, subjects will be administered pre-treatment assessing relevant personality traits and post-treatment assessments of mood.

Inclusion Criteria:

• Healthy subjects without past or current psychiatric or neurological disorders
• Right-handedness

Exclusion Criteria:

• History of head injury;
• Medical or psychiatric illness.
• High blood pressure, general cardio-vascular alterations
• History of drug or alcohol abuse or addiction.
• Allergy against medications or general strong allergies
• Sleep disorders.
• Visual or motor impairments