Retrospective self-reported recall of childhood symptoms of ADHD is often the only approach available to define childhood symptoms of ADHD in adults. The aim of this study was to evaluate the recall accuracy and factors associated with its reliability in a large population-based sample of adults. This study is of clinical relevance as retrospective recall may determine the positive or negative diagnosis of ADHD in an individual.
Data from individuals from the 1993 Pelotas Birth Cohort who were followed-up from childhood to adulthood* were used in this study. In 2015, at the age of 22, individuals were traced† and underwent a comprehensive psychiatric evaluation, including an assessment for ADHD. The validity of retrospective recall on the presence of childhood ADHD symptoms was analysed by including available data on the presence of ADHD symptoms at the age of 11. A clinical assessment was conducted and included participant information regarding gender, birth weight, exposure to tobacco during pregnancy and skin colour; questionnaires on schooling years and child abuse were also included. A mental-health evaluation at the age of 11 was assessed with the self- and parent-report Brazilian Portuguese version of the Strengths and Difficulties Questionnaire (SDQ).‡ Data from the hyperactive behaviour subset of the SDQ was used to confirm the presence of several ADHD symptoms in childhood.§ When participants were 22 years old, they underwent face-to-face interviews to obtain information on health, schooling and behaviour; this psychiatric assessment was based upon the Brazilian version of the Mini-International Neuropsychiatric Interview (M.I.N.I.)|| and included psychiatric disorders highly associated with ADHD. The Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5TM) was used to assess for ADHD in adults.
Of the individuals who were traced from the Pelatos Birth Cohort, 3810 were assessed at the age of 22 regarding mental-health outcomes, ADHD diagnosis and ADHD symptoms in childhood. Of these, 518 (14.4%) had a current presentation of ADHD regardless of childhood symptoms, 162 of which positively endorsed the presence of several childhood symptoms of ADHD by retrospective self-reported recall (ADHD prevalence of 4.5%). However, based on the information that was collected on ADHD symptoms at 11 years of age, rather than retrospective self-reported recall, 201 participants were considered to have ADHD (prevalence of 5.6%).
Demographics and psychiatric comorbidities
Participants with current ADHD at 22 years of age were more frequently women (311/518 [60.0%], p < 0.001), were exposed to more tobacco during pregnancy (p = 0.022) and suffered more frequently from child abuse (p < 0.001) compared with those without ADHD. Participants with current ADHD also had a higher prevalence of psychiatric comorbidities including major depressive disorder, bipolar disorder, social phobia, generalised anxiety disorder, post-traumatic stress disorder and antisocial personality disorder in comparison with those without ADHD (p < 0.001 for all).
Accuracy of retrospective recall of childhood ADHD symptoms
As mentioned above, 162/518 participants positively endorsed the presence of childhood ADHD symptoms; however, only 66 (40.7%) were true-positive cases. For the remaining 356 participants that negatively endorsed the presence of childhood ADHD symptoms, only 221 (62.1%) were true-negative cases. Thus, the recall accuracy of participants with current ADHD for the presence of ADHD symptoms in childhood was 55.4 (95% confidence interval [CI] 51.0–59.7), with a sensitivity of 32.8 (95% CI 26.4–39.8), a specificity of 69.7 (95% CI 64.3–74.7), and a positive and negative predictive value of 40.7 (95% CI 34.7–47.1) and 62.1 (95% CI 59.2–64.9), respectively. To prevent biases, an analysis considering only ADHD cases with severe impairment was also performed. Although only 145 participants were identified as having severe impairment, the accuracy did not differ and remained at 55.9%, with a sensitivity of 40.4%, a specificity of 65.9% and a positive and negative predictive value of 43.4% and 63.0%, respectively.
Factors associated with retrospective recall inaccuracy
The multivariate model of the regression analyses found that social phobia (1.383 [95% CI 1.077–1.775, p = 0.011) was positively associated with false-positive endorsement of childhood ADHD symptoms, and current inattention symptoms (0.944 [95% CI 0.898–0.992], p = 0.024) were negatively associated. The false-negative endorsement of symptoms of ADHD in childhood were positively associated with male gender (1.462 [95% CI 1.126–1.899, p = 0.004]) and non-White individuals (1.311 [95% CI 1.007–1.705, p = 0.044]) but was negatively associated with higher schooling levels (0.472 [95% CI 0.252–0.884, p = 0.019]).
This study has some limitations that need to be considered when interpreting the results. The 1993 Pelotas Birth Cohort study had a 26.4% attrition rate in the 2015 wave (Gonçalves et al. 2018); however, the retention rates obtained could be considered representative of the original sample and were relatively balanced for men and women. For participants with ADHD, there was a predominance of females and the diagnostic process for diagnosing ADHD in this study could have increased both the false-negative and false-positive rates as it differed from the ‘gold standard’. Moreover, this study only accounted for two cross-sectional evaluations at the age of 11 and 22, and the number of participants in this study may not represent the whole population of ADHD in the cohort as many participants may have gone into ADHD remission during adolescence. Finally, these findings should be interpreted with caution since epidemiological evaluations are less comprehensive than clinical studies and could be prone to false results.
In conclusion, the authors state that self-reported recall on the presence of childhood symptoms collected from adults with current symptoms of ADHD could be an invalid method to provide a diagnosis of ADHD. Moreover, as there are no clinical characteristics that are strongly associated with improving the validity of self-reported recall, the authors suggest that clinicians should focus on characterising ADHD based on current symptoms rather than trying to define cases based on potentially inaccurate recall.
*The 1993 Pelotas Birth Cohort included 5249 participants representing 99.1% of all live-born children from maternity hospitals in the urban area of Pelotas, Brazil, during 1993. From 1993 to 2015, several waves of evaluation were conducted which were initiated at the perinatal period and repeated at the ages of 11, 15, 18 and 22
†From the 4003 individuals who were traced (retention rate of 76.3%), 193 were deceased. From the remaining 3810 individuals, 3781 underwent a comprehensive psychiatric evaluation and an assessment for ADHD. However, 180 individuals did not have information on ADHD at the age of 11; therefore, the final sample comprised 3601 individuals
‡The SDQ is a 25-item questionnaire which is divided into five subscales assessing emotional symptoms, conduct problems, hyperactive behaviour, peer relationships and prosocial behaviour. Each subscale has five statements with three possible answers (‘not true’, ‘somewhat true’ or ‘certainly true’ and is scored from 0 to 2) and results in a score that ranges from 0 to 10
§The hyperactive behaviour subset has five affirmatives regarding restlessness, fidgeting, poor concentration, impulsivity and finishing tasks. Individuals with a score ≥7 by either self- or parent-report were considered to have ‘several ADHD symptoms’ in childhood
||The M.I.N.I specific modules were applied for major depressive disorder, bipolar disorder, social anxiety disorder, generalised anxiety disorder, post-traumatic disorder and antisocial personality disorder
Breda V, Rohde LA, Menezes AMB, et al. Revisiting ADHD age-of-onset in adults: to what extent should we rely on the recall of childhood symptoms? Psychol Med 2019; Epub ahead of print.
Gonçalves H, Wehrmeister FC, Assunção MCF, et al. Cohort profile update: the 1993 Pelotas (Brazil) Birth Cohort follow-up at 22 years. Int J Epidemiol 2018; 47: 1389-1390e.