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Do People Really Change?

An article by Seth J. Gillihan Ph.D.

"Personality" is a word used to describe traits that are consistent across time and place. For example, we expect a highly extraverted person to be outgoing at home, at work, and at school. While personality is not a perfect predictor of behavior, it does give us a general idea of how someone is likely to think and act.

The authors of a new review article note that personality can change over long periods of time—for example, we tend to become more responsible and emotionally stable as we age. These changes generally unfold over many years, and seem to reflect a natural developmental process.

The researchers set out to answer an important related question: Can treatment change personality over a short period of time? They focused on the "Big Five" personality traits of extraversion, emotional stability, openness, conscientiousness, and agreeableness.

Roberts and colleagues reviewed over 200 studies that measured personality traits both before and after some type of intervention and included a control group. Interventions included primarily medications and various forms of psychotherapy for a psychological condition, and lasted 24 weeks on average. Their analyses revealed some intriguing results:

  1. Treatment can indeed change personality. Average changes were in the small-to-medium range, suggesting they would be noticeable to the individual and people in his or her life. For example, a person who's easily upset may have an easier time handling stressors. The effects on personality were the same regardless of age or sex.

  2. Personality changes endured over time. Many of the studies the authors reviewed included a follow-up period after the treatment ended, lasting on average about 6 months. Treatment-related changes held steady or even increased during the follow-up interval, even a year or more later. 

  3. Some personality traits were more responsive to treatment. The largest effect was on emotional stability (the reverse of neuroticism), the smallest on openness to experience. Extraversion showed the second greatest change. The authors note that these differences could reflect traits that are more likely to change, but could also reflect what the treatments were targeting. For example, treatment of anxiety or depression would focus on increasing emotional stability.   

  4. A wide range of interventions led to personality change. Although cognitive, behavioral and supportive therapies has slightly larger effects, other types of treatment were also effective, with medication showing the smallest effect. 

  5. Amount of change depended on what the treatment was for. People being treated for anxiety and personality disorders (not surprisingly) changed the most, while those receiving treatment for eating and substance use disorders showed the least personality change. 

What are the implications of these findings? First, as the authors note, they suggest that personality change can happen relatively quickly. Additional analyses showed that treatment needed to last for at least 4 weeks to significantly affect personality. However, after 8 weeks, additional treatment did not lead to greater change. 

The authors had an important caveat: It's possible that a person's personality may have changed as a result of the condition that brought the person to treatment. For example, an episode of depression may have significantly decreased a person's level of emotional stability.

Thus what looks like an increase in emotional stability due to treatment could actually be an effect of treatment on depression, which subsequently restores the person's pre-depression emotional stability. This explanation cannot be ruled out based on existing data.

I do suspect, based on my own experience as a therapist, that a lot of the personality change in treatment is actually a return to a person's level of functioning before their anxiety, depression, or other condition. People often come to treatment because they feel like they're not their best selves—no longer as patient, agreeable, relaxed, or outgoing. As treatment takes hold people often describe feeling "more like themselves" again. Family members will say they feel like they have their loved one back.

If you've thought about starting therapy because you feel disconnected from the person you used to be, consider this additional benefit of treatment: You'll probably feel not just better but more like the best version of you. 

Roberts, B. W., Luo, J., Briley, D. A., Chow, P. I., Su, R., & Hill, P. L. (2017, January 5). A systematic review of personality trait change through intervention. Psychological Bulletin. Advance online publication. doi:10.1037/bul0000088  

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