A new study from Northwestern University found that some people who take antidepressants undergo profound personality changes. Researchers found that many patients grew more extroverted and less neurotic when they underwent such a drug regime.

The study found that those patients who experienced a shift in personality were those less likely to relapse back into depression.

• The study, which was led by Dr. Tony Tang, involved 240 adults with moderate to severe depression.
  
• Half of the study subjects took the drug Paxil for four months, while 60 received therapy without medication, and another 60 were given a sugar pill and no therapy whatsoever.
  
• Those who took the sugar pills showed early improvements that were sometimes almost as great as those who took the real drugs, but they showed no personality changes.
  
• Some who took Paxil underwent sudden personality changes.
  
• Their scores measuring neuroticism improved as quickly as most adults do over a lifetime, and they did it in two months.

Americans spent $9.6 billion last year on selective serotonin reuptake inhibitors or SSRIs, which increase levels of a brain chemical linked to feeling content.

The study appeared in the journal Archives of General Psychiatry.