Why is cognitive ability associated with psychological distress and wellbeing? Exploring psychological, biological, and social mechanisms

Why is cognitive ability associated with psychological distress and wellbeing? Exploring psychological, biological, and social mechanisms. Markus Jokela. Personality and Individual Differences, Volume 192, July 2022, 111592. https://doi.org/10.1016/j.paid.2022.111592

Highlights

• Multiple mechanisms may explain why cognitive ability is related to better mental health.

• Socioeconomic status, engagement in pleasant daily activities, and adaptive coping styles were most important.

• Biomarkers and social relationships did not account for the associations of cognitive ability.

Abstract: This study examined whether associations between cognitive ability and mental health (depression, anxiety, and psychological wellbeing) could be accounted for by different categories of risk factors: socioeconomic status, engagement in pleasant activities, coping/appraisal, social relationships, biological risk factors (inflammation, cortisol, heart-rate variability), and reaction time. Participants were from the Midlife in the United States study (n = 1744; mean age = 54, range 25 to 84). Adjusting for social relationships, biological risk factors, or reaction time had almost no influence on the association between cognitive ability and mental health. Adjusting for engagement in pleasant activities attenuated the associations with depression and anxiety by one-fourth; adjusting for coping/appraisal by one-third; and adjusting for socioeconomic status by one-fifth. These attenuations were larger for the associations with positive affect and life satisfaction. These findings suggest that the association between cognitive ability and mental health may be partly explained by cognitive-behavioral mechanisms and the protective influence of socioeconomic status.

Keywords: IntelligenceDepressionAnxietyMechanismWellbeingMIDUS

4. Discussion

Cognitive ability Among the variables included in this analysis, cognitive-behavioral factors and socioeconomic status were the most plausible mechanisms explaining why cognitive ability is related to lower levels of depression and anxiety, and with higher positive affect and life satisfaction. Biological factors, social relationships, and reaction time did not help to explain the associations.

The magnitude of the associations with symptoms of depression and anxiety ranged between standardized β = −0.12 to β = −0.19. These are not large associations with the conventional metrics of psychology. However, these standardized coefficients of cognitive ability were larger than the standardized coefficients of education, household income, CRP, and IL-6, and they were about the same as for the number of friends (see Supplementary Table 4). These are well-established sociodemographic and biological risk factors for depression and anxiety, so cognitive ability can be considered at least on par with other common risk factors for poor mental health. Given that mental health is determined by multiple biological, psychological, and social factors, one would not expect any single variable to overshadow all the other risk factors.

Some limitations need to be noted. First, all the psychosocial factors were self-reported, so their correlations with mental health outcomes might have been inflated by common informant bias. Second, the study design was observational, so the results can only suggest domains of overlap with the risk factors but not demonstrate causal pathways. The study design was longitudinal in that the mental health outcomes were assessed ~2 years after cognitive assessment and the psychosocial risk factors, so reverse causation or concurrent assessment may not have been as problematic as they would have been in a cross-sectional study design; the analysis did not, however, include adjustments for baseline mental health. In addition, the time lag was different for the covariates assessed in the main survey (few months before assessment of cognitive ability) than for covariates assessed in the biomarker survey (about two years after assessment of cognitive ability), which might have influenced their relative contributions. Third, the different categories of risk factors (e.g., social relationships vs. biological risk factors) were assessed with different types and numbers of indicators, which needs to be kept in mind when interpreting their relative contributions. Fourth, the current study focused on specific covariate categories but did not include a measure of “general fitness factor” that has been suggested to represent an individual's genetic quality, which might help to explain the physical health associations of intelligence (Arden et al., 2009). Finally, this study considered only linear associations of cognitive ability; there have been suggestions that very high cognitive ability might also be related to poorer health, manic symptoms in particular (Gale et al., 2013), but the overall evidence for curvilinear associations is very limited (Brown et al., 2021).

Cognitive-behavioral approach is one of the most influential frameworks in understanding mental health problems (Beck & Haigh, 2014). It emphasizes the interplay between thoughts, behaviors, and emotions, and focuses on modifying people's thoughts and behavioral patterns. For example, the method of behavioral activation is based on finding ways to engage in activities that the person enjoys, thereby providing positive reinforcement (Mazzucchelli et al., 2010). This is directly related to the Pleasant Events Schedule used in the present study, which showed that individuals with higher cognitive ability engaged in more pleasant activities, including laughing, sleeping well, being with other people, having discussions, and working out. They also derived less pleasure from some activities, such as shopping, praying or meditating, and taking a relaxing bath. The associations with pleasant social activities are in contrast to some earlier findings suggesting that individuals with higher intelligence would not enjoy the company of others as much as those with lower intelligence (Li & Kanazawa, 2016). The current results suggest that higher cognitive ability is related to more active engagement with a broad range of pleasant activities, though not all activities (Fig. 1). Pleasant activities associated with cognitive ability could account for one-fifth of its associations with symptoms of depression and anxiety.

Problem-focused coping tackles difficult circumstances by looking for ways to actively solve and modify those circumstances. Emotion-focused coping, by contrast, turns the person's attention to the emotional reactions triggered by the difficult circumstances, which is often not adaptive. Cognitive-behavioral perspective emphasizes the flexibility of appraisals, that is, the possibility of interpreting a given situation from multiple perspectives, which gives more flexibility for the individual to respond. Higher cognitive ability was related to more adaptive coping styles (i.e., higher problem-focused and lower emotion-focused style), which helped to account for one-third of its associations with symptoms of depression and anxiety. This could be due to the better problem-solving skills associated with cognitive ability. However, cognitive ability was not related to the other four self-reported scales that assessed how individuals adjust their behavior when encountering obstacles, and how well they are able to modify and control their thoughts and emotions.

Social relationships are important predictors of many mental health problems, with lack of friends and interpersonal conflicts being a major source of distress (Wang et al., 2018). Except for receiving more support from friends, cognitive ability was unrelated to received support and strain from others, and the number of friends. Social relationships were therefore not relevant for the association between cognitive ability and mental health. Of the biological factors included in this study, cognitive ability was related to lower inflammation, but the biological factors were also not important for the association between cognitive ability and mental health. Similarly, some theories of intelligence suggest that the lower-level information processing might be the crucial factor underlying cognitive abilities, and reaction time has been suggested as one mechanism that might explain why higher cognitive ability predicts longevity (Deary & Der, 2005). However, reaction time did not help to explain why cognitive ability was related to better mental health.

Socioeconomic status may promote better mental health by presenting more resources and helping to buffer against life stressors. As previously reported by other studies (Ali et al., 2013; Cheng & Furnham, 2014), adjusting for socioeconomic status attenuated the association of cognitive ability with symptoms of depression and anxiety, but it accounted only for one-fifth of the association, which suggests that socioeconomic status may not be the main, or even major, factor in explaining the mental health associations of cognitive ability.

In addition to symptoms of depression and anxiety, cognitive ability was also related to higher psychological wellbeing, as measured by positive affect and life satisfaction. These associations were related mostly to the same covariates as depression and anxiety, but these covariates were more influential in explaining the associations with psychological wellbeing: coping styles, pleasant activities, and socioeconomic status each accounted for ~50% of the associations of cognitive ability. When adjusted for all the covariates together, cognitive ability was no longer independently associated with positive affect or life satisfaction. This implies that the covariates identified in this study were more important mechanisms for psychological wellbeing than for depression and anxiety.