Valid inference from the investigation of mental health relies – among others – on the assumption of no measurement error. However, it is well known that data from self-reported measures are likely to be biased by some process that is driven by the respondent’s personality and/or circumstances. We capitalised on data available in two nationally representative birth cohorts, the National Child Development Study (1958 birth cohort) and the 1970 British Cohort Study to formally test the longitudinal measurement equivalence of the nine-item version of the Malaise Inventory, a measure of psychological distress. The inclusion of identical assessments of mental health in adulthood in both cohorts allowed us to evaluate their measurement properties and investigate whether the passage of time has differentially affected the interpretation of mental health assessments. To do so, we employed methods within the generalised latent variable measurement modelling framework and related extensions for formally testing measurement invariance. We found that the passage of two decades and more in both cohorts have not influenced how participants respond to the short version of the Malaise Inventory. The observed scalar invariance of the short version of the Malaise Inventory implies that potential sources of bias such as age effects, survey design, period effects, or cohort specific effects did not influence the way participants in the two cohorts respond to the symptoms described in the Malaise Inventory. Our results offer some reassurance for the extent to which self-reported mental health survey questions are affected by systematic sources of error.
Life course trajectories of affective symptoms (depression and anxiety) are heterogenous. However, few studies have investigated the role of early life risk factors in the development of these trajectories. The present study aimed to: (1) derive latent trajectories of affective symptoms over a period of more than 50 years (ages 13–69), and (2) examine early life risk factors for associations with specific life course trajectories of affective symptoms.
Participants are from the MRC National Survey of Health and Development (NSHD) (n = 5,362). Affective symptoms were measured prospectively at ages 13, 15, 36, 43, 53, 60–64 and 69. A latent variable modelling framework was implemented to model longitudinal profiles of affective symptoms. Twenty-four prospectively measured early life predictors were tested for associations with different symptom profiles using multinomial logistic regression.
Four life course profiles of affective symptoms were identified: (1) absence of symptoms (66.6% of the sample); (2) adolescent symptoms with good adult outcome (15.2%); (3) adult symptoms only (with no symptoms in adolescence and late life) (12.9%); (4) symptoms in adolescence and mid adulthood (5.2%). Of the 24 early life predictors observed, only four were associated with life course trajectories, with small effect sizes observed.
People differ in their life course trajectories of anxiety and depression symptoms and that these differences are not largely influenced by early life factors tested in this study.