It remains uncertain whether long-term use of benzodiazepines is associated with age-related cognitive decline, and if cognitive ability in early life is the driver of any association. This study examines the association of cognitive ability in young adulthood with later use of benzodiazepines and explores whether the use of benzodiazepines during adult life is associated with cognitive decline in late midlife.

The study samples include cognitive tests on the Børge Priens Prøve (BPP) from the conscription board examination (age 19 years) from 335 513 men born 1949–1961 and data from re-examinations of 5183 men 44 years later. Cognitive decline was defined as the difference between scores at the conscription board and the re-examination. Information on purchases of benzodiazepines was obtained from the Danish National Prescription Registry, 1995–2022. Associations were analysed using Cox proportional hazards and linear regression.

In total, 120 911 (36%) men purchased benzodiazepines during a follow-up of 20 years. Lower cognitive scores in young adulthood were associated with a higher risk of initiating benzodiazepines (hazard ratio [95% CI] = 0.71[0.68–0.75]). Men with the highest cumulative use of benzodiazepines had larger cognitive decline (β-coefficient [95% CI] = −1.66 [−2.09 to −1.23] BPP scores) compared with never users. Current benzodiazepine users showed a larger cognitive decline than never users (β-coefficient [95% CI] = −2.42[−3.18 to −1.66] BPP scores) and this partially explained the above association. These estimates for cognitive decline were relatively small and may lack clinical relevance.

Low cognitive ability increases the risk of benzodiazepine use in adulthood and cognitive decline is more pronounced in those with the highest benzodiazepine use compared with never-use, but the difference lacks clinical significance.

Schizophrenia (SZ) and autism spectrum disorders (ASD) are characterized by difficulties in theory of mind (ToM). We examined group differences in performance on a ToM-related test and associations with an estimated IQ.

Participants [N = 1227, SZ (n = 563), ASD (n = 159), and controls (n = 505), 32.2% female] completed the Reading the Mind in the Eyes Test (RMET) and assessments of cognitive ability. Associations between IQ and group on RMET were investigated with regression analyses.

SZ (d = 0.73, p < 0.001) and ASD (d = 0.37, p < 0.001) performed significantly worse on the RMET than controls. SZ performed significantly worse than ASD (d = 0.32, p = 0.002). Adding IQ to the model, SZ (d = 0.60, p < 0.001) and ASD (d = 0.44, p < 0.001) continued to perform significantly worse than controls, but no longer differed from each other (d = 0.13, p = 0.30). Small significant negative correlations between symptom severity and RMET performance were found in SZ (PANSS positive: r = −0.10, negative: r = −0.11, both p < 0.05). A small non-significant negative correlation was found for Autism Diagnostic Observation Schedule scores and RMET in ASD (r = −0.08, p = 0.34).

SZ and ASD are characterized by impairments in RMET. IQ contributed significantly to RMET performance and accounted for group differences in RMET between SZ and ASD. This suggests that non-social cognitive ability needs to be included in comparative studies of the two disorders.

Bereaved youth are at greater risk for adverse mental health outcomes, yet less is known about how social context shapes health for bereaved children. Ecosocial theory is employed to conceptualize bereavement in the context of sociodemographic factors.

This longitudinal study used data from the Avon Longitudinal Study of Parents and Children. Of the 15,454 pregnancies enrolled, 5050 youth were still enrolled at age 16.5 and completed self-report questionnaires on life events and emotional/behavioral symptoms.

Sociodemographic precursors associated with parent, sibling, or close friend bereavement included maternal smoking, parental education levels, and financial difficulties. The significant yet small main effect of higher cognitive ability, assessed at age 8, on reduced emotional/behavioral symptoms at age 16.5 (β = −0.01, SE = 0.00, p < 0.001) did not interact with bereavement. Bereavement of a parent, sibling, or close friend was associated with a 0.19 point higher emotional/behavioral symptom log score compared to non-bereaved youth (95% CI: 0.10–0.28), across emotional, conduct, and hyperactivity subscales.

Descriptive findings suggest sociodemographic precursors are associated with bereavement. While there was an association between the bereavement of a parent, sibling, or close friend and elevated emotional/behavioral symptoms, cognitive ability did not moderate that effect.

Depression and chronic inflammatory medical conditions have been linked to impaired cognitive ability. However despite frequent comorbidity, their combined association with cognitive ability has rarely been examined.

This study examined associations between self-reported depression and chronic inflammatory diseases and their interaction with cognitive performance in 456,748 participants of the UK Biobank, adjusting for sociodemographic and lifestyle factors. Numbers with available data ranged from 94,899 to 453,208 depending on the cognitive test.

Self-reported depression was associated with poorer performance compared to controls in several cognitive tests (fully adjusted models, reaction time: B = 6.08, 95% CI = 5.09, 7.07; pairs matching: incidence rate ratio = 1.02, 95% CI = 1.02, 1.03; Trail Making Test B: B = 1.37, 95% CI = 0.88, 1.87; Digit Symbol Substitution Test (DSST): B = −0.35, 95% CI = −0.44, −0.27). Self-reported chronic inflammatory conditions were associated with slower reaction time (B = 3.79, 95% CI = 2.81, 4.78) and lower DSST scores (B = −0.21, 95% CI = −0.30, −0.13). No interaction effects were observed.

In this large, population-based study we provide evidence of lower cognitive performance in both depression and a comprehensive category of chronic inflammatory conditions. Results are consistent with additive effects of both types of disorder on cognitive ability. Clinicians should be aware of such effects, particularly as cognitive impairment is linked to poorer disease outcomes and quality of life.

Cognitive ability and problem behaviour (externalising and internalising problems) are variable and inter-related in children. However, it is not known if they mutually influence one another, if difficulties in one cause difficulties in the other, or if they are related only because they share causes.

Random-intercept cross-lagged models adjusted for confounding were fitted to explore this in 17,318 (51% male) children of the UK’s Millennium Cohort Study at ages 3, 5, 7, 11 and 14 years. Externalising and internalising problems were assessed using the parent-reported Strengths and Difficulties Questionnaire. Cognitive ability was measured using standardised scores of age-appropriate validated cognitive ability assessments. Where multiple cognitive assessments were available a single score was derived using principal components analysis.

There was much evidence for cross-domain longitudinal effects in childhood, especially for cognitive ability (on both internalising and externalising problems and in both males and females) and externalising problems (on internalising problems in both genders and cognitive ability in males). Bidirectional effects were childhood-limited, gender-specific and less consistent. The consistent bidirectional associations were, in males, between externalising problems and cognitive ability, and, in females, between externalising and internalising problems (although the effects of internalising problems were weak). In adolescence, only externalising problems had cross-domain effects such that, in both genders, they were associated with lower cognitive ability in subsequent measurements and increased levels of internalising problems.

In either childhood or adolescence, reducing behavioural problems could have both emotional and cognitive benefits. In childhood, improving cognitive skills could reduce both emotional and behavioural problems.

Social disadvantage consistently predicts both self-reported distress and clinically diagnosed disorders such as depression. Yet, many individuals who are exposed to disadvantage do not report high levels of distress. This study extends our recent work showing that high cognitive ability may protect against the negative health consequences of exposure to disadvantaged backgrounds. We test whether this ‘buffer effect’ exists across clinically relevant indices of mental health in a population-representative sample.

In total, 27 985 participants were drawn from the UK Household Longitudinal Study (Understanding Society). Clinical diagnoses of depression and clinically relevant measures of psychological distress [i.e. Short Form-12 (SF-12) Mental Component, General Health Questionnaire (GHQ)] and trait neuroticism were assessed. Cognitive ability was derived from performance on word recall, verbal fluency and numerical ability tasks. Early-life disadvantage was gauged using family background measures assessing parental education and occupation at age 14.

Background disadvantage predicted increased levels of reported psychological distress and neuroticism. These associations were moderated by cognitive ability. Across all available mental health measures, the negative association between early-life disadvantage and poor adult mental health was strongest at low (−1 s.d.) cognitive ability and was no longer evident at high (+1 s.d.) levels of cognitive ability.

The results provide support for a cognitive buffering hypothesis linking high cognitive ability to a decrease in the magnitude of the social gradient in mental health. Those disadvantaged by both low socioeconomic status and low cognitive ability may benefit from targeted prevention and treatment programmes aiming to reduce socioeconomic disparities in mental health.

Being breastfed in infancy has been shown to benefit neurodevelopment. However, whether the benefits persist to old age remains unclear.

We examined the associations between breastfeeding and its duration on cognitive ability in young adulthood and old age, and on aging-related cognitive change over five decades. In total, 931 men from the Helsinki Birth Cohort Study born in 1934–1944 in Finland took the Finnish Defence Forces Basic Intellectual Ability Test (total and verbal, arithmetic and visuospatial subtest scores) twice, at ages 20.2 and 67.9 years, and had data on breastfeeding (yes v. no) and its duration (‘never breastfed’, ‘up to 3’, ‘3 to 6’ and ‘6 or more months’). Linear and mixed model regressions tested the associations.

At 20.2 years, breastfed men had higher cognitive ability total and visuospatial subtest scores [mean differences (MDs) ranged between 3.0–3.9, p values < 0.013], and its longer duration predicted higher cognitive ability total and arithmetic and visuospatial subtest scores (MDs ranged between 3.0 and 4.8, p values < 0.039). At 67.9 years, breastfed men had higher total cognitive ability and all subtest scores (MDs ranged between 2.6 and 3.4, p values < 0.044) and its longer duration predicted all cognitive ability scores (MDs ranged between 3.1 and 4.7, p values < 0.050). Verbal subtest scores decreased over five decades in men who were never breastfed or were breastfed for 3 months or less, and increased in those breastfed for longer than 3 months.

Neurodevelopmental advantages of breastfeeding and its longer duration persist into old age, and longer duration of breastfeeding may benefit aging-related change, particularly in verbal reasoning ability.