Subthreshold ADHD Research Articles

Heightened suicidal risk in ADHD and subthreshold ADHD: Understanding the role of psychiatric comorbidities

ObjectivesRecently, adult ADHD diagnoses have increased, complicating treatment when comorbid with other disorders. Subthreshold ADHD(sADHD) also poses challenges, especially with comorbidities and suicidality. This study explores psychiatric comorbidities' role in ADHD and sADHD suicidality. MethodsWe analyzed microdata from the National Mental Health Survey of Korea 2021 to examine the association of ADHD on comorbidities and suicide-related behaviors. ResultsOf the 5511 participants, 194(3.52 %) were diagnosed with ADHD, and 775(14.1 %) had sADHD. In 12-month prevalence, suicidal ideation and plans were more prevalent in both ADHD and sADHD patients than in controls, with higher odds ratios(ADHD vs. control OR 12.87; suicidal ideation, 54.06; suicidal plan, sADHD vs control OR 8.26; suicidal ideation, 17.63; suicidal plans). Lifetime suicidal ideation and plans were notably associated with alcohol use disorder(OR 6.15 in ideation, 3.83; plan) and nicotine use disorder in participants with ADHD(OR 5.36 in ideation, 5.31; plan), whereas sADHD associations were found with alcohol use disorder(OR 1.80 in ideation) and depressive disorder(OR 1.90 in ideation) compared to the controls. Additionally, differences in suicidal behavior between sADHD and ADHD were identified for alcohol use disorder(OR 3.42 in ideation, 4.15; plan) and nicotine use disorder(OR 4.02 in ideation, 4.98 in plan). ConclusionThese results indicated a heightened risk of psychiatric comorbidities and suicidal ideation or plans in the ADHD and sADHD groups. These results suggest the need for a more diverse focus on comprehensive mental health assessments and proactive support for patients with ADHD, regardless of symptom severity.

Family Functioning in Children With ADHD and Subthreshold ADHD: A 3-Year Longitudinal Study

Objective: To compare family functioning over time for elementary school children with Attention-Deficit/Hyperactivity Disorder (ADHD; N = 179) and subthreshold ADHD (ST-ADHD; N = 86), to children without ADHD (Control; N = 212). Method: ADHD was assessed using the Conners 3 ADHD Index and Diagnostic Interview Schedule for Children IV. At baseline, 18-month follow-up and 36-month follow-up, parents completed measures assessing a range of family functioning domains. Results: At baseline, the ADHD group reported higher psychological distress, less parenting self-efficacy, less parenting consistency, and more stressful life events; and both groups reported poorer family quality of life (QoL) and greater parenting anger. Trajectories were largely similar to controls (i.e., stable over time), but unlike controls, ADHD and ST-ADHD groups showed lessening parent-partner support and parenting warmth, respectively; and both groups showed worsening aspects of family QoL. Conclusion: Families of children with ADHD and ST-ADHD report persistently poor or worsening family functioning; highlighting a need for tailored psycho-social supports.

Should children with sub-threshold ADHD predominantly inattentive subtype (ADHD-I) symptoms be treated with Sensory ıntegration therapy? A case-control study.

Objective: Sensory integration therapy is one of the promising preventive therapy options for behavioral and developmental disorders. Hypothesizing a degree of parallelism, this study provides an insight into the effectiveness of the sensory integration therapy potencies for school-aged children with subthreshold ADHD predominantly inattentive subtype. Method: The study was a single-arm clinical trial and 20 patients aged 7–10 years with subthreshold ADHD predominantly inattentive subtype, were included. The sensory integration intervention was prepared in accordance with sensory modulation principles and intervention strategies and lasted 12 weeks with two sessions per week. The effectiveness was assessed using the Conner’s teacher/parent scales, the Clinical Global Impression scale, the Canadian Sensory integration Performance Measure and the Sensory Profile. Results: The rate of patients with typical or better performance in auditory processing domain of the Sensory Profile was found significantly increased after sensory integration therapy; 9 patients (45%) before and 15 patients after (75%) (p=0.031). The rates of participants with typical or better performance in inattention–distractibility factor score of the Sensory Profile were found significantly increased after sensory integration therapy; 6 before (30%) and 16 after (80%) (p=0.006). Conclusion: Sensory integration therapy focuses on supporting persons with varied disability terms to engage in daily life activities that they find significant and purposeful. Difficulties experienced by individuals with subthreshold attention-deficit hyperactivity disorder are addressed in this study and aspects of daily life are explored while swiping through different sensory modalities. Impaired auditory processing improvable through sensory integration therapy was observed in these children.

Efficacy of Omega-3 and Korean Red Ginseng in Children with Subthreshold ADHD: A Double-Blind, Randomized, Placebo-Controlled Trial

Objective: The purpose of the present study was to investigate the efficacy of combined omega-3 and Korean red ginseng supplementation on ADHD symptoms and cognitive function in children with subthreshold ADHD. Method: 120 children from 6 to 12 years with subthreshold ADHD were enrolled in this 12-week, double-blind, randomized, placebocontrolled study. The primary outcome was measured by Attention-Deficit Hyperactivity Disorder Rating Scale (ADHD-RS). Children Behavior Check List (CBCL), and neuropsychological tests assessing attention, memory, and executive function were included as secondary primary outcome measures. Results: Significant effects on the scores of ADHDRS, as well as several subscales of CBCL including ADHD and attention problem subscales were revealed. Conclusion: The combination of omega-3 and Korean red ginseng may have beneficial effects in children with subthreshold ADHD. Increased clinical awareness of ADHD symptoms even at a subthreshold level is needed.

Early Predictors of De Novo and Subthreshold Late-Onset ADHD in a Child and Adolescent Cohort

Objective: The study aimed to identify early childhood risk factors for de novo and subthreshold late-onset ADHD. Method: ADHD symptoms were assessed in 9,875 participants from the Twins Early Development Study (TEDS) using the Conners’ Parent Rating Scale at ages 8, 12, 14, and 16 years, along with other childhood characteristics and adolescent outcomes. Multinomial logistic regressions were implemented to identify early childhood predictors of late-onset ADHD and childhood-onset persistent ADHD, with non-ADHD controls as the reference category. Results: Male sex, increased childhood conduct problems, and low socioeconomic status predicted de novo late-onset ADHD. Additional risk factors predicted subthreshold late-onset ADHD and childhood-onset persistent ADHD. Late-onset ADHD symptoms were also accompanied by increased co-occurring behavioral and emotional problems. Conclusion: Findings of different childhood predictors between subthreshold and de novo late-onset ADHD suggest further investigation into time-varying environmental and biological factors driving psychopathological changes is warranted to fully characterize late-onset ADHD.

Six-year follow-up study of combined type ADHD from childhood to young adulthood: Predictors of functional impairment and comorbid symptoms

BackgroundADHD in childhood is associated with development of negative psychosocial and behavioural outcomes in adults. Yet, relatively little is known about which childhood and adulthood factors are predictive of these outcomes and could be targets for effective interventions. To date follow-up studies have largely used clinical samples from the United States with children ascertained at baseline using broad criteria for ADHD including all clinical subtypes or the use of DSM III criteria. AimsTo identify child and adult predictors of comorbid and psychosocial comorbid outcomes in ADHD in a UK sample of children with DSM-IV combined type ADHD. MethodOne hundred and eighteen adolescents and young adults diagnosed with DSM-IV combined type ADHD in childhood were followed for an average of 6years. Comorbid mental health problems, drug and alcohol use and police contact were compared for those with persistent ADHD, sub-threshold ADHD and population norms taken from the Adult Psychiatric Morbidity Study 2007. Predictors included ADHD symptomology and gender. ResultsPersistent ADHD was associated with greater levels of anger, fatigue, sleep problems and anxiety compared to sub-threshold ADHD. Comorbid mental health problems were predicted by current symptoms of hyperactivity-impulsivity, but not by childhood ADHD severity. Both persistent and sub-threshold ADHD was associated with higher levels of drug use and police contact compared to population norms. ConclusionsYoung adults with a childhood diagnosis of ADHD showed increased rates of comorbid mental health problems, which were predicted by current levels of ADHD symptoms. This suggests the importance of the continuing treatment of ADHD throughout the transitional years and into adulthood. Drug use and police contact were more common in ADHD but were not predicted by ADHD severity in this sample.

Co-occurrence of attention-deficit hyperactivity disorder symptoms with other psychopathology in young adults: parenting style as a moderator

The extent to which parenting styles can influence secondary psychiatric symptoms among young adults with ADHD symptoms is unknown. This issue was investigated in a sample of 2284 incoming college students (male, 50.6%), who completed standardized questionnaires about adult ADHD symptoms, other DSM-IV symptoms, and their parents’ parenting styles before their ages of 16. Among them, 2.8% and 22.8% were classified as having ADHD symptoms and sub-threshold ADHD symptoms, respectively. Logistic regression was used to compare the comorbid rates of psychiatric symptoms among the ADHD, sub-threshold ADHD and non-ADHD groups while multiple linear regressions were used to examine the moderating role of gender and parenting styles over the associations between ADHD and other psychiatric symptoms. Both ADHD groups were significantly more likely than other incoming students to have other DSM-IV symptoms. Parental care was negatively associated and parental overprotection/control positively associated with these psychiatric symptoms. Furthermore, significant interactions were found of parenting style with both threshold and sub-threshold ADHD in predicting wide-ranging comorbid symptoms. Specifically, the associations of ADHD with some externalizing symptoms were inversely related to level of paternal care, while associations of ADHD and sub-threshold ADHD with wide-ranging comorbid symptoms were positively related to level of maternal and paternal overprotection/control. These results suggest that parenting styles may modify the effects of ADHD on the risk of a wide range of temporally secondary DSM-IV symptoms among incoming college students, although other causal dynamics might be at work that need to be investigated in longitudinal studies.

The latent classes of subclinical ADHD symptoms: Convergences of multiple informant reports

The purpose of the present study was to conduct latent class analysis on the Hyperactivity scale of the Strengths and Difficulties Questionnaire in order to identify distinct subgroups of subclinical ADHD in a multi-informant framework. We hypothesized a similar structure between teachers and parents, and differences in symptom severity across latent classes. Data was collected from a non-referred sample of children aged 8-13 years. We performed latent class analyses on parent (n = 383) and teacher (n = 391) ratings of the Hyperactivity scale items from both versions of the questionnaire. Those children who had ratings from both informants (n = 272) were included in the cross-informant analyses, in which the similar or equivalent classes across raters were determined. A three-class solution for parent report and a five-class solution for teacher report emerged in the subsample of boys. For girls, a three-class structure for parents and a four-class structure for teachers were optimal. Besides non-symptomatic groups, mild and severe combined classes, mild inattentive-impulsive classes, and among boys, a mild hyperactive-impulsive class was obtained. The cross-informant analyses demonstrated that quite similar subgroups were detached regardless of informant; however, the teacher classes were somewhat more elaborated. The results are in line with the previous latent class analytic studies, and support the combination of dimensional and categorical approaches. The importance of milder symptoms and sub-threshold ADHD categories are emphasized for the fields of neuropsychology, neuroscience, and education, as well as for diagnosis and personalized treatment.

Subthreshold conditions as precursors for full syndrome disorders: a 15‐year longitudinal study of multiple diagnostic classes

There has been increasing interest in the distinction between subthreshold and full syndrome disorders and specifically whether subthreshold conditions escalate or predict the onset of full syndrome disorders over time. Most of these studies, however, examined whether a single subthreshold condition escalates into the full syndrome form of that disorder. Equally important, though, is whether subthreshold conditions are likely to develop other full syndrome disorders and whether these associations are maintained after adjusting for comorbidity. A 15-year longitudinal study of subthreshold psychiatric conditions was conducted with 1,505 community-drawn young adults. We examined whether 1) subthreshold major depression, bipolar, anxiety disorders, alcohol use, substance use, conduct disorder and/or ADHD were precursors for the corresponding (homotypic) full syndrome disorder; 2) subthreshold conditions were precursors for other (heterotypic) full syndrome disorders; and 3) these homotypic and heterotypic precursors persisted after adjusting for comorbidity. Subthreshold major depression, anxiety, alcohol use, substance use, and conduct all escalated into their corresponding full syndrome and nearly all homotypic developments were maintained after adjusting for comorbid subthreshold and full syndrome conditions. Many heterotypic associations were also observed and most remained after controlling for comorbidity, particularly among externalizing disorders (e.g., alcohol, substance, conduct/antisocial personality disorder). Many subthreshold conditions have predictive validity as they may represent precursors for full syndrome disorders. Alternatively, dimensional conceptualizations of psychopathology which include these more minor conditions may yield greater validity. Subthreshold conditions may represent good targets for preventive interventions.

The use of health care services and psychotropic medication in a community sample of 9-year-old schoolchildren with ADHD

To examine the prevalence of the use of health care services and psychotropic medication within a community sample (N = 283) of 9-year-old school children and, more specifically, to evaluate the use of prescribed stimulants. Data from the second follow-up phase of the "Study of Attention Deficit Maastricht" (SAM) were analysed. Assessments at age 9 included a structured psychiatric interview with parents, behaviour and family situation questionnaire, IQ estimate and global assessment scale. Use of health care services and medication was obtained by the DICA-R and from the Youth Health Care records. About 190 children of the selected sample had at least one child psychiatric diagnosis, 26 (14%) of them were clinically referred and 12 (6%) received stimulants. Of the children with ADHD (N = 45), 10/45 (22%) received stimulants. Conversely, 2 out of 12 children who were treated with stimulants did not meet full DSM-IV diagnostic criteria, but were subthreshold ADHD cases. The treatment status was highly dependent on being clinically referred. The major finding of our survey is a lack of referral to child mental health services, and associated underdiagnosis and undertreatment, particularly in children with ADHD. There is a critical need to translate and implement the diagnostic and treatment guidelines to clinical practice.

Cognitive strengths and deficits in schoolchildren with ADHD

Few studies provide detailed analyses of the various aspects of the entire cognitive profile of children with ADHD. Cognitive test data were analysed for 10- to 11-year-old children with (1) ADHD, (2) subthreshold ADHD and (3) milder attention and/or learning problems, and compared with normative data. Thirty-two had ADHD and 10 met the criteria for subthreshold ADHD, prevalence rates of 5.4% and 1.6%, respectively. On a group level, children with ADHD/subthreshold ADHD, and those with milder attention and/or learning problems had almost identical cognitive profiles for the 13 subtests comprising the WISC III, with particularly low results on the arithmetic, coding, information and digit span subtests (ACID profile). When analyzed individually, a complete or incomplete ACID profile (three of four subtests) was equally common in children with ADHD/subthreshold ADHD and in children with milder problems, found in about 1/5. The relative strengths of both groups were in areas demanding logical thinking, reasoning and common sense. The specific ACID profile is as common in children with ADHD as in those with minor attention and/or learning problems. The cognitive weaknesses reflected in the ACID profile might play a role as an underlying factor in various developmental disorders.

Substance Use among ADHD Adults: Implications of Late Onset and Subthreshold Diagnoses

Diagnosing ADHD in adults is difficult when the diagnostician cannot establish an onset prior to the DSM-IV criterion of age seven or if the number of symptoms does not achieve the DSM threshold for diagnosis. These diagnostic issues are an even larger concern for clinicians faced with adults with substance use disorders (SUD). The present study compared four groups of adults: full ADHD subjects who met all DSM-IV criteria for childhood onset ADHD, late onset ADHD subjects who met all criteria except the age at onset criterion, subthreshold ADHD subjects who did not meet full symptom criteria, and non-ADHD subjects who did not meet any of the above criteria. Diagnoses were by the Structured Clinical Interview for DSM-IV, and the Drug Use Severity Index (DUSI) was used for self-report of substance use. Cigarette and marijuana use was significantly greater in all ADHD groups relative to non-ADHD controls. Although usage rates of other drugs failed to reach significance, the ADHD groups were more likely to have used each drug (except alcohol) compared with the non-ADHD group. The late onset and full ADHD groups were more likely to have endorsed ever having a problem due to use of cigarettes, alcohol, or marijuana and reported more trouble resisting use of drugs or alcohol. The full ADHD group was more likely than the other groups to have reported "getting high" as their reason for using their preferred drug. Adults with ADHD have elevated rates of substance use and related impairment. Data about late onset ADHD provides further support for the idea that the DSM-IV age at onset criterion is too stringent. In contrast, subthreshold ADHD seems to be a milder form of the disorder, or perhaps a heterogeneous group of true ADHD cases and false positives.

The prevalence and co-morbidity of subthreshold psychiatric conditions.

In previous studies of subthreshold conditions, co-morbidity has been largely ignored. The purpose was to examine rates of co-morbidity among subthreshold disorders and between subthreshold and full-syndrome disorders for the major non-psychotic classes of disorders from DSM-IV. Participants came from the Oregon Adolescent Depression Project (mean age=16.6 years; females=52.1%). On the basis of a diagnostic interview (K-SADS), participants were assigned to eight subthreshold disorders (MDD, bipolar, eating, anxiety, alcohol use, substance use, conduct, ADHD). Of the 1704 adolescents in the analyses, 52.5% had at least one subthreshood disorder. Of those, 40.0% had also experienced a co-morbid subthreshold condition, and 29.9% of those had a second co-morbid subthreshold condition. Of those with a subthreshold, 36.4% also had a full syndrome. The subthreshold forms of externalizing disorders were co-morbid with each other. As expected, subthreshold anxiety was co-morbid with subthreshold MDD but subthreshold anxiety was also co-morbid with subthreshold alcohol, conduct, and ADHD. The pattern of co-morbidities was nearly identical for males and females. The hypotheses that externalizing disorders would be co-morbid with other externalizing disorders and that internalizing disorders would be co-morbid with other internalizing disorders was partially supported. Co-morbidities between subthreshold disorders and between subthreshold disorders and full syndrome should impact future research and clinical practice. The assessment of subthreshold disorders needs to include the assessment of other subthreshold and full-syndrome conditions.

Reassessment of ADHD in a historical cohort of children treated with stimulants in the period 1969-1989.

The operational diagnostic criteria for ADHD or HKD were not at hand in Denmark before 1994, when WHO's International Classification of Diseases -10 (ICD-10) was introduced. The criteria for ADHD/HKD were well known at our clinic, but when treating children with stimulants the criteria used clinically prior to 1994 were less specific than today. The aims of this paper are to examine the prevalence of ADHD in a historical cohort of children treated with stimulants during the period 1969-1989 and to reassess a wide range of comorbid disorders and sociodemographic characteristics in order to compare aspects of the given treatment with the modern recommendations. At our clinic 208 children (183 boys) were given stimulants during the period 1969-1989. Case records on these probands were reassessed retrospectively for DSM-IV criteria regarding ADHD and comorbid disorders as well as for characteristics of stimulant treatment. Sixty-five percent met full criteria for an ADHD diagnosis. Including Subthreshold ADHD as many as 81 % of the cohort were re-diagnosed with ADHD. Prevalence rates of conduct problems and anxiety disorder were similar to previous prospective ADHD studies. The use of stimulants during the period 1969-1989 were in accord with modern guidelines. This cohort is comparable to other clinically based ADHD cohorts as regards inattentive, hyperactive/impulsive symptoms, comorbidity, impairment, gender differences, intelligence and socio-economic status (SES).