Written by: Anne-Laura Van Harmelen, Senior Research Associate at the Department of Psychiatry, University of Cambridge
Recalling positive memories may help lower the risk of depression in young people who have had a difficult childhood, our latest study has found.
Depression often emerges during the teenage years. Many mental health problems in later life are linked to adverse experiences in early life, such as poverty, parents having mental health problems, being bullied, neglect and abuse. Mental illness often emerges earlier in young people who have experienced adversity and is more severe and less responsive to treatment, so it is vital that we have a better understanding of how we can reduce vulnerability before depression emerges.
Memories are critical to our sense of self, decision-making and mental health. We spend much of our waking time ruminating about past events and planning the days ahead. Some have suggested that this constant mind wandering makes us unhappy, but it has also been found that reminiscing about happy events may increase positive feelings and dampen the release of stress hormones after a stressful event.
My colleague (Adrian Dahl Askelund) and I wanted to know whether remembering positive experiences could protect against stress. To do this, we collected measures of stress hormones, mood and negative thoughts in 427 14-year-old teenagers at risk for depression due to adversity experienced during childhood.
Our results, published in Nature Human Behaviour, showed that those who recalled more specific positive memories (a happy 13th birthday, say) when entering the study, had fewer negative thoughts about themselves and lower levels of the stress hormones cortisol one year later. This may suggest that training teenagers to recall specific positive memories could reduce the risk of depression.
Interestingly, recalling specific positive memories lowered negative thoughts and depressive symptoms in those who experienced at least one stressful event during the 12 months of our study. But recalling positive memories did not affect negative thoughts and depression in those who had not experienced such negative events.
Our finding suggests that recalling specific positive events may promote mental health resilience especially in the face of stress in teenagers at risk of depression. In particular, recalling positive memories when something bad happens (such as “when I helped that little boy who fell and hurt himself”) may protect against negative thoughts (“I am useless”). This may, in turn, lead to fewer depressive symptoms.
Our findings could help develop new methods for preventing depression in teenagers and for improving treatment. One possibility is that training teenagers with a history of childhood adversity in recalling specific positive memories may help build resilience and prevent mental ill health in these young people.
One increasingly popular habit that could help with increasing access to positive memories is keeping a journal. Although this is something that needs to be studied further, it may be beneficial to write down both positive and negative events that have happened, reflecting on how they affected your thoughts and mood. However, this may not be an effective method for people who struggle with clinical levels of depression. In these cases, our findings may be best applied in established treatments, to potentially improve their effects.
Some people who suffer from clinical depression may struggle with remembering specific positive events. For these people, training positive memory recall may work best if it is combined with established treatments, such as cognitive behavioural therapy (CBT).
In CBT, patients are often trained in using techniques to challenge negative thoughts. Our study suggests that being able to recall specific positive events from the past (“that day I got that high mark for maths”) may help disconfirm negative thoughts (“I am dumb”).
Future research should investigate whether this ability to recall specific positive memories could be trained and whether this would boost therapy outcomes in vulnerable youth.
Anne-Laura Van Harmelen receives funding from the Royal Society and MQ.