Mood disorders are a leading cause of health loss in New Zealand, however, current treatments do not work or are not well tolerated by large number of people who suffer from these disorders. Increasing evidence from animal studies and anecdotal reports suggest that low doses of serotonergic 2A receptor agonists are able to positively improve symptoms of depression and anxiety. However, this has yet to be adequately tested in humans. In this research we will conduct a randomised control clinical trial using repeated low doses of a serotonergic 2A receptor agonist in healthy human volunteers. We will assess its effects on mood, cognition, and brain function as a key step before testing in a clinical patient group. Conducting a healthy volunteer trial is a critical step before conducting future clinical trials in patients with depression and anxiety.