Hi, Your friend has palpitations, & taking the history into account he had been having these symptoms mostly due to stress and anxiety. It had been proven that people with palpitations have associated anxiety or stress. palpitations can be precipitated by Anxiety and depression Caffeine, Alcohol, drugs such as cocaine, amphetamines, ecstasy, beta-agonists, theophyllines, calcium channel blockers, antiarrhythmic drugs, antidepressants, antipsychotics. Does he have the symptoms while at work or test? because when occur at rest it s generally not harmful. Palpitations when occur in isolation without any associated factors like Breathlessness, Blackout episodes, Chest pain, etc are generally bening. If he has it repeatedly then you can advise him to go for Thyroid Function Tests, 2D Echocardiography, Holter Monitoring/Event Recorder. Some Lifestyle Modifications like regular exercises, yoga, meditation, engaging in some creative activities that s would be of his liking would help him.