A Review of Canadian Diagnosed ADHD Prevalence and Incidence Estimates Published in the Past Decade.

(1) Background: ADHD is recognized as one of the most common neurodevelopmental disorders. The worldwide prevalence of ADHD is estimated at 5.3%; however, estimates vary as a function of a number of factors, including diagnostic methods, age, sex and geographical location. A review of studies is needed to clarify the epidemiology of ADHD in Canada. (2) Methods: A search strategy was created in PubMed and adapted for MEDLINE and PsycINFO. Papers were included if they examined diagnosed ADHD prevalence and/or incidence rates in any region of Canada, age group and gender. A snowball technique was used to identify additional papers from reference lists, and experts in the field were consulted. (3) Results: Ten papers included in this review reported on prevalence, and one reported on incidence. One study provided an overall prevalence estimate across provinces for adults of 2.9%, and one study provided an overall estimate across five provinces for children and youth of 8.6%. Across age groups (1 to 24 years), incidence estimates ranged from 0.4% to 1.2%, depending on province. Estimates varied by age, gender, province, region and time. (4) Conclusions: The overall Canadian ADHD prevalence estimate is similar to worldwide estimates for adults. Most studies reported on prevalence rather than incidence. Differences in estimates across provinces may reflect the varying number of practitioners available to diagnose and prescribe medication for ADHD across provinces. To achieve a more comprehensive understanding of the epidemiology of ADHD in Canada, a study is needed that includes all provinces and territories, and that considers estimates in relation to age, gender, ethnicity, geographical region, socioeconomic status and access to mental healthcare coverage. Incidence rates need further examination to be determined.

Cytomegalovirus Immunity, Inflammation and Cognitive Abilities in the Elderly.

Reducing the socioeconomic toll from age-related physical and mental morbidities requires better understanding of factors affecting healthy aging. While many environmental, lifestyle, and genetic factors affect healthy aging, this study addressed the influence of cytomegalovirus (CMV) infection and immunity on age-related inflammation and cognitive abilities. Healthy adults 70-90 years old were recruited into a prospective study investigating relationships between anti-CMV immunity, markers of inflammation, baseline measures of cognitive ability, and changes in cognitive ability over 18 months. Humoral and cellular responses against CMV, levels of inflammatory markers, and cognitive abilities were measured at study entry, with measurement of cognitive abilities repeated 18 months later. CMV-seropositive and -seronegative sub-groups were compared, and relationships between anti-CMV immunity, markers of inflammation, and cognitive ability were assessed. Twenty-eight of 39 participants were CMV-seropositive, and two had CMV-specific CD8+ T cell responses indicative of CMV immune memory inflation. No significant differences for markers of inflammation or measures of cognitive ability were observed between groups, and cognitive scores changed little over 18 months. Significant correlations between markers of inflammation and cognitive scores with interconnection between anti-CMV antibody levels, fractalkine, cognitive ability, and depression scores suggest areas of focus for future studies.

Probabilities of ADD/ADHD and Related Substance Use Among Canadian Adults.

Objective: The aim of this study was to estimate the prevalence and probabilities of comorbidities between self-reported ADD/ADHD and smoking, alcohol binge drinking, and substance use disorders (SUDs) from a national Canadian sample. Method: Data were taken from the Public Use Microdata File of the 2012 Canadian Community Health Survey-Mental Health (N = 17 311). The prevalence of (a) smoking, (b) alcohol binge drinking, and (c) SUDs was estimated among those with an ADD/ADHD diagnosis versus those without an ADD/ADHD diagnosis. Results: After controlling for potential socioeconomic and mental health covariates, self-reported ADD/ADHD acted as a significant predictor for group membership in the heaviest smoking, heaviest drinking, and heaviest drug usage categories. Conclusion: Individuals self-reporting a diagnosis of ADD/ADHD were found to have a significantly higher likelihood of engaging in smoking and alcohol binge drinking, and were more likely to meet criteria for SUDs than individuals not reporting an ADD/ADHD diagnosis.

The Influence of Socioeconomic Status on Psychological Distress in Canadian Adults With ADD/ADHD.

OBJECTIVE: The primary purpose of this study was to examine the relationship between socioeconomic status (SES) and psychological distress in individuals self-reporting a diagnosis of attention deficit disorder (ADD)/ADHD. METHOD: This correlational study encompasses cross-sectional data from 488 male and female adults (20-64 years) who reported that they have been diagnosed with ADD/ADHD. Psychological distress was measured with the Kessler Psychological Distress Scale (K10). RESULTS: Adults with ADD/ADHD and high incomes have significantly lower K10 scores than Canadians with ADD/ADHD and low incomes. Income, but not education, was significant in predicting psychological distress among the sample. Canadian adults with ADD/ADHD have an increased risk for developing psychological distress and comorbid psychiatric disorders. CONCLUSION: The findings suggest that negative outcomes associated with ADD/ADHD are not necessarily pervasive. High income may serve as a protective factor for psychological distress among adults with ADD/ADHD.

Prevalence and Correlates of Self-Reported ADD/ADHD in a Large National Sample of Canadian Adults.

OBJECTIVE: The objective of this study was to examine the prevalence and correlates of self-reported attention deficit disorder (ADD)/ADHD in Canadian adults. METHOD: Prevalence of self-reported ADD/ADHD was examined in a large national sample of Canadians ( n = 16,957). Demographic variables, lifetime, and current psychiatric comorbidities were then compared in a group of adults with self-reported ADD/ADHD ( n = 488) and an age- and gender-matched control group ( n = 488). RESULTS: The prevalence of self-reported ADD/ADHD was 2.9%. Significantly higher lifetime and current prevalence rates of major depressive disorder, bipolar I and II disorders, generalized anxiety disorder, and substance use disorders were observed in the ADD/ADHD group compared with the control group. Within the ADD/ADHD group, lifetime and 12-month prevalence rates of major depressive disorder and generalized anxiety disorder were significantly higher in women, whereas lifetime and current rates of some substance use disorders were significantly higher in men. CONCLUSION: In a national sample of Canadian adults, self-reported ADD/ADHD was associated with significant psychiatric comorbidity. Gender differences were also noted.

Cumulative estrogen exposure and prospective memory in older women.

This study looked at cumulative lifetime estrogen exposure, as estimated with a mathematical index (Index of Cumulative Estrogen Exposure (ICEE)) that included variables (length of time on estrogen therapy, age at menarche and menopause, postmenopausal body mass index, time since menopause, nulliparity and duration of breastfeeding) known to influence estrogen levels across the life span, and performance on prospective and retrospective memory measures in a group of 50 postmenopausal women (mean age=69.3years) who, if they were current or former users of estrogen therapy, had started therapy within 5years of menopause. The ICEE was found to be a significant predictor of performance on the Prospective Memory task (F(1)=4.21, p=.046, η(p)(2)=.084). No significant relationship was noted between the ICEE and performance on measures of retrospective memory. The results suggest that the level of cumulative lifetime exposure to estrogen a woman has influences her prospective memory performance later in life and that the influence of reproductive and biological markers of endogenous estrogen exposure are relevant factors to consider when studying the effect of estrogen therapy on cognitive functioning in postmenopausal women. In addition, the finding that performance on a measure of prospective memory, but not performance on measures of retrospective memory, was associated with the ICEE adds further support to the theory that the frontal cortex may be especially sensitive to estrogen.