Can Oxytocin Enhance the Placebo Effect?

The current study included three phases to investigate oxytocin effect on placebo effect:

• In a double-blind, between-subject, placebo controlled design study to investigate the intranasal OXT (24IU) treatment in 66 healthy male subjects using working memory task.
• In a single-blind(subjects were informed that the treatment was oxytocin), between-subject, placebo controlled design study to investigate the intranasal OXT (24IU) treatment in 53 healthy male subjects using working memory task.They were informed that oxytocin would increase memory perfomance by a female experimenter.
• In a single-blind(subjects were informed that the treatment was oxytocin), between-subject, placebo controlled design study to investigate the intranasal OXT (24IU) treatment in 53 healthy male subjects using working memory task. But the subjects were told that oxytocin would decrease the performance by the same female experimenter.
• In a single-blind(subjects were informed that the treatment was oxytocin), between-subject, placebo controlled design study to investigate the intranasal OXT (24IU) treatment in 52 healthy male subjects using working memory task. The subjects were told that oxytocin would increase the performance by a male experimenter.

Memory performance was included as dependant factor. All subjects completed a range of questionnaires measuring personality and affective traits and levels of anxiety: State-Trait Anxiety Inventory (STAI), Beck Depression Inventory (BDI), Interpersonal Trust Scale(ITS).

Inclusion criteria

• Healthy subjects without past or current psychiatric or neurological disorder

Exclusion criteria

• history of head injury;
• claustrophobia;
• medical or psychiatric illness.