A 30-minute lesson in the malleability of personality has long-term benefits for anxious, depressed teenagers

There are many effective psychological therapies to help teenagers with depression, anxiety or other mental health problems. Unfortunately, for various reasons, most teenagers never get access to a professional therapist. To overcome this problem, some researchers are exploring the potential of brief, "single-session" interventions that can be delivered cheaply and easily to many at-risk teenagers outside of a clinical context. In The Journal of Child Psychology and Psychiatry, Jessica Schleider and John Weisz at Harvard University present extremely promising results from their trial of a 30-minute computer session teaching depressed and anxious teenagers that personality is malleable.

To be eligible, the participating teenagers needed to have problematic anxiety and/or depression. Ninety-six teenagers took part, aged 12 to 15, mostly White American. Forty-eight of them were assigned to the 20-to-30-minute session about the malleability of personality. The others, who had the same baseline symptom levels, acted as controls and spent an equal amount of time in a computer-based session of "supportive therapy" learning about emotions and how it's helpful to talk about them. The idea was this would match the experience of being enrolled in the personality change session in all ways except for the all-important content.

The personality session was self-administered on computer and taught the teenagers about neuroplasticity and the idea that behaviours arise from thoughts and feelings in their brains, and that brains are always changing. They heard from older youths saying they believe people can change, and from others saying how they'd used belief in our capacity for change (a "growth mindset") to cope with problems like embarrassment or rejection. The teenagers learned strategies for applying these principles to themselves and they wrote notes to younger children about the malleability of personality traits.

The primary message of the intervention, the researchers said, is that "personal attributes are malleable if we systematically – and with appropriate supports – act to change them. Essentially it reinforces beliefs in behavioral control over the kinds of people we are can can become."

All the teens completed a series of psychological measures before and immediately after whichever session they took part in, and then they took the same measures again three, six, and nine-months later. Their parents also completed some of the same measures about their child. To avoid their own expectations affecting the results, the researchers were kept unaware of which teens were in which condition until the end of the study.

The promising findings include that the teens in the personality change session showed more rapid declines in depression, and nine months later their depression scores had declined more than the control participants' scores (33 per cent fewer of them now had clinically severe levels of depression, compared with 11 per cent fewer among the control group). These benefits were mirrored in parents' ratings of their children's depression.

The results for anxiety weren't as good, but still showed promise – the personality change intervention led to greater declines in symptoms at nine months based on parents' reports, although not based on the teenagers' self-reports.

As hoped, compared with the controls, the teenagers in the personality change intervention reported a stronger increase in their belief that your personality is something you can change. Further clues as to how the personality change intervention helped the teenagers come from measures of their belief in their ability to deal with adversity by controlling their own behavior (e.g. whether they agreed with statements like "I can be popular with kids my age, if I really try"; "I can do well on tests if I try really hard") and their own emotions (e.g. "I can usually find something good to like, even in a bad situation" or ""When I have a problem that I can't change, I can do something to take my mind off it.").

Across the follow-up period, the teens in the personality change intervention showed larger increases in their sense of control over their own behavior, as compared with the control participants (there was no difference in their sense of control over their emotions). This makes sense given the personality intervention's focus on behavioral control as a means to influence our personalities.

Schleider and Weisz said their "mindset" intervention teaching that personality is malleable is "highly cost-effective and scalable", meaning it could be delivered to all new pupils arriving at a secondary school, for example. They added "these are the first findings we know of suggesting that a 30-minute, self-administered program may help reduce depression, and to a lesser degree, anxiety, in high-symptom and high-risk youths." They believe the intervention may have such strong and enduring effects because it focuses on "'keystone beliefs' of high developmental relevance to adolescents".

Another advantage is that for any teens who end up in therapy, the brief personality change session could help lay the groundwork in terms of motivation and helpful beliefs about personal control.

While the results are encouraging, larger trials are needed, the researchers noted, including with teenagers from more ethnically diverse and less affluent backgrounds.