The purpose of this study is to examine the influence of a medicinal cannabinoid agonist versus placebo on behavioural and gut peptide responses to food images and food intake.

Inclusion Criteria:

For healthy volunteers:

1. 20 ≤ BMI ≤ 25
2. Age 18-60
3. Right handed
4. Stable body weight for at least 3 consecutive months at start of study and no history of behavioural, therapeutic or surgical treatment aiming at or leading to weight loss/gain

For obese subjects:

1. BMI > 30
2. Age 18-60
3. Right handed
4. Stable body weight for at least 3 consecutive months at start of the study and no behavioural, therapeutic or surgical treatment aiming at or leading to weight loss/gain for at least 3 consecutive months

For FD patients:

1. FD diagnosis according to 'Rome III' criteria
2. Age 18-60
3. Right handed
4. 5% weight loss since onset of symptoms

Exclusion Criteria:

1. Medical conditions (current or history):

   • Abdominal/thoracic surgery except appendectomy
   • Gastrointestinal, endocrine (especially diabetes), or neurological diseases
   • Cardiovascular, respiratory, renal or urinary diseases
   • Hypertension
   • Food or drug allergies
   • Head trauma with loss of consciousness

2. Psychiatric disorders:

   • Eating disorders
   • Psychotic disorders
   • Major depressive disorder
   • Somatoform disorder

3. Medication use:

   • No history of cannabis use or any other drug of abuse for at least 12 months prior to the study
   • All medication except oral contraception;

4. Known allergy to dronabinol and/or sesam oil

5. Pregnancy, plans to conceive or refusal to take adequate precaution to avoid pregnancy

6. Subjects who refuse to abstain from driving during the study