Patterns of negative thoughts, and changes in the way we process information (including our attention, motivation and memory processes), also known as cognitive bias, are common features of depression. It may be that these cognitive biases are part of what leads people to become depressed, and what keeps depression going once we are depressed. They may also be part of what makes us vulnerable to developing depression again in the future.
Importantly, these biases could be tackled by cognitive training, which makes them promising treatment targets and therefore important to understand more about. As an example, Michelle Moulds previously blogged about rumination focused cognitive behaviour therapy (CBT) as a promising prevention approach in adolescents.
Most prior research has focused on a cognitive bias in relative isolation, without looking at how the cognitive biases may be inter-related. Also, most prior research has been undertaken in adult samples; adolescence is a time of rapid cognitive development, for example, in the prefrontal cortex (Blakemore, 2012). It is also a time of particular vulnerability to developing depression which can have long-lasting consequences. Finally, where cognitive biases have been examined in adolescents, studies have often recruited community samples rather than clinical samples.
Faith Orchard and Shirley Reynolds from the University of Reading, set out to explore whether the combination of cognitive biases an individual is experiencing is a better predictor of how severe their depression is than any one particular cognitive bias. To address some of the shortcomings of prior research, they recruited adolescents, including a clinical sample.
This study recruited two samples of teenagers (age 12-18). They recruited 212 teens from the community via schools, and also 84 teenagers from Child and Adolescent Mental Health Services (CAMHS).
The participants completed a number of questionnaires:
- The Mood and Feelings Questionnaire was used to assess depression symptoms.
- Interpretation bias was assessed using the Ambiguous Scenarios Test for Depression in Adolescents, which presents a series of 20 scenarios, and asks the respondent to describe what they think will happen, and to rate how pleasant this predicted outcome would be.
- Self-evaluation bias was assessed through a 30-item self-description questionnaire which lists positive (e.g. kind), negative (e.g. stupid) and neutral adjectives, each of which the respondent is asked to rate for how well it describes them.
- The participants completed an immediate recall task to assess their recall memory bias.
- The clinical sample also completed a diagnostic interview.
- The analysis found that cognitive biases were inter-related.
- The more cognitive biases an individual had, the greater the severity of their depression symptoms.
- This is interesting, as the authors were able to show that it is the combination of cognitive biases which have an additive effect, and overall, the combined cognitive biases predicted 60% of the variance in depression severity.
- Variation in depression severity was explained mostly by negative self-evaluation, as well as by interpretation bias.
- In the clinical sample, these two biases correctly predicted 71% of those who met the criteria for a diagnosis of depression, which is at least as good as the depression questionnaire used (which correctly predicted 70% of those with a diagnosis of depression).
The authors conclude that:
In adolescents, depression symptoms and diagnosis are significantly associated with specific cognitive biases (and not others).
The results reported here suggest for the first time, that for adolescents, negative evaluation of the self is strongly associated with depression severity and with a diagnosis of depression.
If cognitive biases can be assessed reliably and easily, they may offer an alternative method to identify individuals at risk of depression.
Strengths and limitations
Recruiting from both the community and a clinical setting ensured that the sample captured a wide range of individuals with and without depression, and at varying levels of severity.
However, the cross-sectional design precludes conclusions about causality, so we can’t tell from this research whether these cognitive biases are merely a consequence of depression rather than being a cause of depression.
There was some missing data, which may have introduced bias. Whilst the clinical sample completed a gold standard diagnostic interview as well as the depression questionnaire, comparable diagnostic information was not available for the community sample who did not complete the diagnostic interview.
Self-report measures are, of course, liable to social desirability biases and are inherently subjective in nature.
A further limitation is that the self-description adjectives were a list given to respondents, and it would be useful for future research to use qualitative methods to enable spontaneous reporting.
Implications for practice
From these findings, it seems to be important to consider the combination of cognitive biases that an individual with low mood is experiencing. Of particular importance in adolescence, which is the time of emergence of the self-concept, are self-evaluative biases. The authors have since published further details about the specific kinds of self-evaluation biases which differed between the community and clinical samples; ‘worthless’ and ‘useless’ seemed particularly prominent in the latter, but interestingly, self-evaluations of prosocial behaviour (e.g. ‘kind’) did not differ between the samples (Orchard, Pass & Reynolds, 2018). Negative self-evaluation may also provide fruitful clues to a need to further assess for the presence of low mood and depression.
Working clinically with adolescents, these findings would cue me to be more conscious of negative self-evaluative biases and to help clients to recognise the patterns of when these occur. We could work on them beginning to respond to these in a different way, whilst encouraging the development of a more positive self-concept.
Conflicts of interest
Orchard F, Reynolds S. (2018) The combined influence of cognitions in adolescent depression: Biases of interpretation, self-evaluation, and memory. Br J Clin Psychol. 2018 Nov;57(4):420-435. doi: 10.1111/bjc.12184. Epub 2018 May 25.
Blakemore SJ. (2012) Imaging brain development: The adolescent brain. NeuroImage, 61, 397– 406. https://doi.org/10.1016/j.neuroimage.2011.11.080
Orchard F, Pass L, Reynolds S. (2018) ‘I Am Worthless and Kind’; the specificity of positive and negative self-evaluation in adolescent depression. British Journal of Clinical Psychology, doi:10.1111/bjc.12215 [PubMed abstract]