Serge Brand of the Psychiatric University Clinics in Basel, Switzerland, and his colleagues surveyed 113 teenagers at around 17 years of age, asking them to complete questionnaires about their conduct and mood and to keep a log of their sleep patterns. Of those, 65 indicated they had recently fallen in love and experienced intense romantic emotions.
The lovestruck teenagers showed many behaviours resembling "hypomania" – a less intense form of mania. For example, they required about an hour less sleep each night than teens who didn't have a sweetheart. They were also more likely to report acting compulsively, with 60% saying they spent too much money compared with fewer than 30% of teenagers who were not in love.
Moreover, the lovestruck teens were more than twice as likely to say they had lots of ideas and creative energy. Worryingly, they were also more likely to say they drove fast and took risks on the road.