Can anti-depressants change your personality?

A study found that people’s tendencies for being neurotic or extroverted changed even more than their mood during antidepressant treatment.

What do we know?

Different personality traits, often inherited from our parents, are linked to our chances of getting depression. One of the strongest links is with what scientists called neuroticism. This means a tendency towards negative emotions and emotional instability.

For example, someone who had a strongly neurotic personality might be more likely to interpret personal comments about them as critical, and to find them more upsetting than someone who had a less neurotic personality.

Another personality trait is extroversion. People with extroverted personalities are sociable and outgoing, and have a tendency towards positive emotions. Generally, people who are extroverted seem less likely to become depressed, although not all studies show this.

Antidepressants called selective serotonin-reuptake inhibitors (SSRIs) are used to treat depression. They boost the amount of a chemical called serotonin in your brain. Serotonin is used to carry messages around the brain.

Doctors previously thought that SSRIs lifted mood by increasing serotonin when people didn't have enough of it. Although people being treated may have said they felt more sociable, or got upset less easily, this was seen as a side effect of their improved mood, not a change in their basic personality.

But researchers are now interested in whether serotonin actually makes a difference to personality traits, and whether changes in these traits are what improves people’s mood, rather than the other way around.

This new study looked at how both personality traits and depression changed in three groups of patients. One group received the antidepressant paroxetine (brand name Seroxat),  another group took dummy (placebo) pills, and the third group had cognitive therapy, a talking treatment that has been shown to work well for depression.

The new study

People treated with either paroxetine or cognitive therapy improved in all three areas studied: they were less depressed, less neurotic, and more extroverted. Interestingly, people treated with placebo drugs were also less depressed, but had little change in their personality scores for being neurotic or extrovert.

Using standard measurements for personality traits and depressive symptoms, the researchers found that the changes in personality for people treated with paroxetine were much greater than the change in depression alone. For the people treated with cognitive therapy, most of the change in personality traits could be explained by improvements in depression.

Finally, people who took paroxetine and had the biggest drops in neuroticism during the study were the least likely to become depressed again during the following year, even if they’d stopped taking treatment during that year.

How reliable are the findings?

It might be argued that the separation of mood from aspects of personality is artificial, since the two are so intertwined and the relationship between them complex. Also, the researchers did a lot of calculations, comparing different groups with each other, and looked at changes in personality and depression scores within groups. The problem with this is that the more calculations you do, the more likely it is that one or more result will have come about by chance alone. And the numbers of people in the study (240 in total) was not large.

Despite this, most of the results fitted with the theory that SSRIs have an effect on personality traits, over and above their effect on depression. So it’s likely the results are fairly reliable, although it would be good to see them confirmed in a bigger study.

Where does the study come from?

The researchers were from a number of universities in the USA. The study was published in the Archives of General Psychiatry. The study was funded by grants from the US Government’s National Institute of Mental Health, and the drugs were provided by the manufacturer of paroxetine.

What does this mean for me?

You may find the idea of drugs that change your personality disturbing. In fact, it’s important to bear in mind the research is only looking at specific aspects of personality that are closely associated with mood, such as extroversion.

That said, this is an interesting study for anyone prone to depression. Many people would prefer to be less neurotic, or more outgoing, and these changes might protect them from depression. Some people might be wary about changing the way they are, in order to feel better.

What should I do now?

If you are suffering from depression, it’s important to get help. There are lots of treatments for depression, not just antidepressant drugs. Talk to your doctor about what sort of treatments might be suitable for you.