Pathways of Comorbidity of Attention Deficit Hyperactivity Disorder & Oppositional Defiant Disorder in the Adolescent Population

Sismanidou Theodora

Doctoral Candidate, Department of Education and Social Work Sciences, University of Patras, Social Worker at 1^st KEDASY A΄Athens theodora_sismanidou@hotmail.com

Farmakopoulou Ignatia

Assistant Professor, Department of Educational Sciences and Social Work, University of Patras ifarmakop@upatras.gr

Abstract Attention-deficit and hyperactivity disorder (ADHD) is a common neurodevelopmental condition with a global prevalence of 3.4% (Polanczyk et al., 2015). The number of symptoms is extensive, where some of these symptoms are serious and the person's functionality shows a significant impairment (Maniadaki & Kakouros, 2016). This paper focuses on a PhD thesis that aims to investigate the social and family factors that influence the occurrence of comorbidity of ADHD and Oppositional Defiant Disorder (ODD) in the adolescent population. Quantitative methodology is used in this study, through a selective sampling approach. Purposive selection of participants is carried out in General Gymnasiums and High Schools in the Prefecture of Attica. The necessary actions have been taken to acquaint the necessary ethics permits from the competent bodies. The latter are The Research Ethics Committee of University of Patras, the Regional Directorate of Secondary Education of the Prefecture of Attica and the Ministry of Education, Religion and Sports. The ultimate goal of the research is to design a manual for Parents and Mental Health Specialists regarding Psychoeducation and Counseling of Parents of Adolescents diagnosed with ADHD, in cases where the above-mentioned factors are found to contribute to the comorbidity of ADHD and ODD in the adolescent population.

Key words: Attention Deficit Hyperactivity Disorder, Oppositional Defiant Disorder, Comorbidity

1.  Introduction

The first scientific report on ADHD was made by the doctor Grichton in 1798. More specifically, he noticed that people with this disorder show an inability to maintain their attention, which comes from an abnormal sensitivity of the nerves. The conceptual approach of ADHD was reformed with the release of the DSM-V, where the following three types of this disorder were formulated: a) the inattentive type, b) the hyperactive or impulsive type, and c) the combined type. In particular, children in whom the inattentive type predominates are often described as daydreamers and exhibit anxiety or depression and are more likely to be withdrawn, although they show fewer conduct and behavior problems compared to the other two ADHD types. The majority of children with the hyperactive or impulsive type meet the diagnostic criteria for the combined type. Additionally, regarding the irritability of these children or adolescents, a key characteristic of this disorder is the outbursts of anger - which are extreme and easily triggered - but their duration is short (lasts a few hours at most) (Stringaris & Taylor, 2021).

The ADHD significantly affects psychosocial functioning and development (Young, et al, 2021). This disorder is associated with many deficits in the neuropsychological domain, with some individuals showing neuropsychological deficits although one should take neuropsychological heterogeneity into account. With regard to neurodevelopmental deficits, there is a strong association of the disorder with executive function, which includes cognitive flexibility, working memory, and inhibition (Thorel et al., 2017). The most basic symptoms of the disorder involve the inability to regulate neural symptoms and affect the neurotransmitters norepinephrine and dopamine in the frontal lobes.

Some functional imaging studies find that subcortical abnormalities reflect the onset of ADHD and persist throughout life regardless of symptom change, whereas the variable clinical course of adolescent ADHD is determined by cortical plasticity. Integrating the understanding of neural processes with genomic risk could elucidate the mechanisms underlying the complex course of adolescent ADHD (Sudre et al, 2020).

Higher levels of executive function difficulties are associated with reduced attention. In studies conducted, parents report high levels of hyperactivity and difficulty with emotional regulation. Deficits in emotional and executive regulation are associated with ADHD symptoms (Landis, et al., 2021).

One of the largest imaging studies carried out on ADHD on subcortical structures, in addition to observing a smaller volume in the basal ganglia (amygdala, caudate nucleus, hippocampus, shell) that he mentions, also adds the nucleus accumbens, identifying a more general variation in transcranial volume, which is smaller compared to that of a person without ADHD. It also validates the theory of delayed brain maturation in people with ADHD, as the volume of the above brain structures (except for the thalamus and ventral pallidum) grows during the person's adulthood (Hoogman et al. 2017).

A large percentage (50%-70%) of adolescents diagnosed with ADHD during childhood still meet the criteria for the disorder. In fact, even in the event that the symptoms of hyperactivity-impulsivity show remission to some extent, the symptoms of inattention as well as the accompanying secondary obstacles arising from ADHD persist, intensify and become even more complicated (Zigouris, 2018).

Sleep disorders have been observed in adolescents with ADHD. This is of significant importance due to the fact that sleep instability has been found to be a risk factor for early delinquency (Jackson & Vaughn, 2017). Furthermore, exposure to violent scenes in the media influences adolescents with ADHD and activates impulsive behavior through imitation of antisocial behaviors. There is also a correlation with video game viewing and the appearance of inattention in adolescents with ADHD (Rydel & Brocki, 2020).

The most common recorded comorbidity of ADHD is with ODD, where the rates reach 35-60% (Curtis et al., 2015). The comorbidity of ADHD & ODD is greater in children and adolescents and especially in those who present the combined type of ADHD (Maniadaki & Kakouros, 2016; Sadek, 2014). The difference in the prevalence of this comorbidity between the two sexes is not clear. Some studies show that the percentages are higher in boys than in girls, while other studies have not identified any gender differences (Karadiamandi, 2021).

Both ADHD and ODD fall under behavioral problems, where they appear to include a wide range of cognitive, interpersonal, social and emotional difficulties. Characteristic elements of ADHD are aggression, reactivity and disobedience. These problems intensify when there is a lack of parental support (Skaloubakas, IEP, xx). Persistence of ADHD and ODD behavioral symptoms into adolescence has been associated with an increased risk of delinquent behavior, substance abuse, anxiety, and depression (Maniadaki & Kakouros, 2016).

The ODD affects 3.3% of all children and adolescents with a prevalence as high as 12.6% (Ter-Stepanian, etal., 2017). The following conceptual approach is characteristically mentioned in the DSM-V: “children with ODD exhibit argumentative, disobedient and unruly behavior without though serious violation of the rights of other people. These children are stubborn, negative and defiant”. On average, 3%-4% of teenagers suffer from some behavioral disorder (conduct disorder, ADHD or ODD (Sultan et al, 2021).

Extreme forms of control (authoritarian or overprotective parenting, physical punishment, psychological control or the lack of control ie indifference) and supervision are associated with a strong presentation of behavioral problems. The authoritarian style of the parent is related to the inability to regulate behavior, low social skills, depression, adjustment difficulties, impulsivity, reduced self-esteem and self-confidence, internalized and externalized behavior problems - with aggression in boys and hyperactivity in girls - even in interactions with peers (Bagan et al., 2019; Chung et al., 2019; Marcone et al., 2018).

In addition, adolescent ADHD is associated with poor academic outcome, and such individuals often experience increased peer rejection, foster alliances foster alliances and attract dysfunctional peer populations. Not only there is a genetic vulnerability to substance use and smoking, but also peer rejection often increases the reinforcing value of involvement with other adolescents who are participating in smoking and negative behaviors. Due to both the developmental and progressive nature of the increasing problems associated with adolescence, there are often deficits in social skills and impaired social relationships. The fact that this is also linked to an inability to process social information and difficulties in problem solving creates in itself an additional challenge (Pudenz, Bames & Howard, 2020).

1. Family Factors Affecting the Occurrence of ADHD & ODD Comorbidity in the Adolescent Population

The ADHD occurs at a higher rate among first-degree relatives In order for the researchers to arrive at the specific findings, genetic research had to be done on families, adopted children and twins (Theodoropoulou, Kouma & Lakmeta, 2021). The parents of children and adolescents with comorbid ADHD and ODD show low self-efficacy regarding their parental role and manifest feelings of frustration, anxiety, confusion, exhaustion and helplessness (Malkoff et al., 2020).

The research of Wiener et al, (2016) examined parenting stress in parents of adolescents with ADHD. The sample included 138 adolescents (84 with ADHD: 52 boys and 32 girls, as well as 54 adolescents without ADHD: 24 boys and 30 girls) aged 13 to 18 years and their parents. Mothers and fathers of adolescent participants completed the Stress Index for Parenting Adolescents. The extent to which clinical levels of adolescent ODD symptoms or externalizing behavior in general were associated with parenting stress depended on who was the rater of these behaviors. Furthermore, beyond adolescent ADHD classification, mothers' self-reported ADHD symptoms were associated with higher parenting stress, and fathers' self-reported ADHD symptoms were associated with lower stress. The results suggest directions to consider for addressing parenting stress when designing interventions for families of adolescents with ADHD.

The long-term research of Kourkoutas & Caldin, (2017) which focused on the effect of the family on the development of hyperactivity and antisocial behaviors, highlighted that relationships within the family should be considered as dynamic and complex reactions of the family and not as individual static interactions, in attempt to adapt to the environment. Adolescents who show comorbidity of ADHD and ODD face difficulties in both their family and social relationships, usually show a low level of self-esteem, and as it was mentioned forehead have a tendency towards delinquency and disobedience and sometimes show some symptoms of depression, in several cases resort to substance abuse (alcohol and drug use) and generally possess a disobedience and transgression towards rules and principles. The relationships that teenagers develop with their parents play an important role in the dynamics and balance or imbalance of the family (Konstandinou, 2020).

1.2 Social Factors Affecting the Occurrence of ADHD-ODD Comorbidity in the Adolescent Population

A study conducted in Germany, involving 474 school-aged children and adolescents, aimed to focus on understanding how individual symptoms of ADHD and ODD are differentially related to functional impairment in the following domains: members' home life of the family, the relationships of the participants with their Professors, the relationships with their classmates, their academic performance and the general psychological pressure they felt. The findings of this research contribute to the importance of analyzing the associations between the aforementioned individual symptoms and the adolescent's functional impairment (Thone et al, 2023).

The socio-economic level of the parents, the way of educating their children, seeking support from Mental Health Specialists and the daily care of a child and teenager with a disorder, are factors that contribute to the increase of parental stress. Parents of children and adolescents with ADHD and especially when there is a comorbidity of ADHD and ODD, report more negative feelings towards their children, adopt less effective strategies for managing behavior problems and have lower emotional empathy (Korpa, 2017).

2. Purpose of the Doctoral Thesis

In the above bibliographic and research review regarding the examination of the factors that possibly influence the occurrence of ADHD comorbidity with ODD, it is important to mention that in Greece there is scarce research in this specific field. For this reason, the current original research is conducted in our country and focuses on the examination of:

1. socio-demographic factors such as the gender, the age of the parents, the psychiatric history of the parents, the place of residence and the size of the residence and the educational level and type of work of the parents, their informal care network and of

• family factors such as their marital status and therefore if they live in a nuclear, single-parent or extended family, the quality of the teenagers' relationship with their parents, but also of the sibling relationship.

The purpose of the research is to investigate the aforementioned factors in the possible occurrence of comorbidity of ADHD & ODD in the adolescent population, as well as to outline the profile of adolescents who only exhibit ADHD but also those who have comorbidity of ADHD & ODD and their parents. Therefore, sketching the profile of adolescents with ADHD and their parents, as well as investigating the quality of the relationship that prevails between parents and adolescents and its effect on the appearance or non-appearance of ODD, are some of the goals of this innovative and current research.

2.1. Research Questions

Some research questions on which the doctoral study is based are the following:  

a) What are the similarities and differences in the clinical picture of adolescents with ADHD and ODD comorbidity, in relation to their gender?

 b) The good quality relationship between parent(s) and adolescent with ADHD    contributes to avoidance occurrence of comorbidity with ODD and correspondingly the conflicting parent/child relationships and adolescent with ADHD contribute to the occurrence of comorbidity with ODD?

c) Does the psychopathology of the parents affect the occurrence of ADHD co-morbidity with ODD?

d) The socio-economic background of the parents affects the occurrence of comorbidity with ODD to adolescents with ADHD?

2.2. Research Questionnaires

As regards the tools applied both to teenagers, parents and teachers, the widespread system SAEBA-Achenbach (2018) is used, as it is an integrated system of quantitative research, i.e. a series of tools that focus on the evaluation of the abilities, the adaptive functionality of children and adolescents and behavioral problems, as well as the collection of data from multiple sources of information (parents/guardians, adolescents and teachers) and is therefore consistent with the purposes of this research.

More specifically,

a) the questionnaire (YSR) (25 pcs) is used for the students, 12-18 age,

b) the questionnaire (CBCL) (25 pcs) for the parents of teenagers and

c) the questionnaire (TRF) (25 pcs) for the teachers

2.3. Participants of the Study

The research study, conducted in the Prefecture of Attica, utilizes quantitative methodology and specifically the approach of selective sampling. A total of 120 teenage students (12-18 years old) are purposefully selected, of which:

1. 120 students aged 12-18, who attend: 

In General Gymnasiums:

-30 students only with ADHD and correspondingly another 30 with comorbidity of ADHD & ODD. So, a total of 60 Gymnasium students.

 Accordingly, in General High Schools:

          -30 students only with ADHD and correspondingly another 30 with comorbidity

           of ADHD & ODD. So, a total of 60 High School students.

• 120-240 Parents of the 120 participating students (ideally both parents).
• 60 Teachers of General High School classes attended by the aforementioned

 categories of participating students.

• 60 General Lyceum Teachers of classes attended by the aforementioned

 categories of participating students.

• Universal Sample of School Social Workers who have worked with the

 participating students.

• Global Sample of School Psychologists they know/have worked with

      participating students.

All participating teenagers have an Evaluation Report from the Centers for Interdisciplinary Evaluation, Counseling and Support (KE.D.A.S.Y.) or Psychiatric Clinics for Children and Adolescents or Medical Education Centers. The Assessment Report includes demographic information (name of child/adolescent, relationship to assessor, occupation of parent), abilities of the child/adolescent (sports and favorite activities, number of friends, relationship with siblings, academic performance), open questions about any illnesses or disabilities), emotional and social problems as well as behavioral problems. In the present study, students who do not show any of the aforementioned two disorders are not included.

In the research, the Ackenbach Scale (2018) is used for both teenagers, parents, and the educational staff of the School Units. The ultimate goal of the doctoral thesis is the preparation of a Manual for parents, mental health specialists and the scientific community in general, regarding the Psychoeducation and Counseling of Parents of adolescents diagnosed with ADHD, in the event that the above-mentioned factors influence the occurrence or non-occurrence of comorbidity ADHD and OOD in the adolescent population.

At the current phase, the researcher has followed all the needed processes for the acquisition of all necessary permits from the relevant organizations. The approval of the Ministry of Education, Religion and Sports, the Regional Directorate of Secondary Education of the Prefecture of Attica and as Ethics issues are concerned, the Research Ethics Committee Application Form of University of Patras has been completed and has been obtained. Therefore, the research is being carried out as well as the completion of the theoretical part of the doctoral thesis.

BIBLIOGRAPHY

• Achenbach, T.M. & Rescorla, L.A. (2018). Handbook for the SAEBA school-age questionnaires and profiles (2nd ed.) (Ed. Alexandra Roussou). Athens: ATHENS.
• Bagán, G., Tur-Porcar, A. M., & Llorca, A. (2019). Learning and parenting in Spanish environments: Prosocial behavior, aggression, and self-concept. Sustainability (Switzerland), 11(19). https://doi.org/10.3390/su11195193
• Chung, S., Zhou, Q., Anicama, C., Rivera, C., & Uchikoshi, Y. (2019). Language Proficiency, Parenting Styles, and Socioemotional Adjustment of Young Dual Language Learners. Journal of Cross-Cultural Psychology, 50 (7), 896–914. Στο: https://doi.org/10.1177/0022022119867394
• Curtis, D. F., Elkins, S. R., Areizaga, M., Miller, S., Brestan- Knight, E., & Thornberry, T. (2015). Oppositional Defiant Disorder. In Kapalka, G. M., Disruptive Disorders and Behaviors: A Concise Guide to Psychological, Pharmacological and Integrative Treatments (pp. 99-119) New York: Routledge.
• Hoogman M, Bralten J, Hibar DP, Mennes M, Zwiers MP, Schweren LSJ, van Hulzen KJE, Medland SE, Shumskaya E, Jahanshad N, Zeeuw P, Szekely E, Sudre G, Wolfers T, Onnink AMH, Dammers JT, Mostert JC, Vives-Gilabert Y, Kohls G, Oberwelland E, Seitz J, Schulte-Rüther M, Ambrosino S, Doyle AE, Høvik MF, Dramsdahl M, Tamm L, van Erp TGM, Dale A, Schork A, Conzelmann A, Zierhut K, Baur R, McCarthy H, Yoncheva YN, Cubillo A, Chantiluke K, Mehta MA, Paloyelis Y, Hohmann S, Baumeister S, Bramati I, Mattos P, Tovar-Moll F, Douglas P, Banaschewski T, Brandeis D, Kuntsi J, Asherson P, Rubia K, Kelly C, Martino AD, Milham MP, Castellanos FX, Frodl T, Zentis M, Lesch KP, Reif A, Pauli P, Jernigan TL, Haavik J, Plessen KJ, Lundervold AJ, Hugdahl K, Seidman LJ, Biederman J, Rommelse N, Heslenfeld DJ, Hartman CA, Hoekstra PJ, Oosterlaan J, Polier GV, Konrad K, Vilarroya O, Ramos-Quiroga JA, Soliva JC, Durston S, Buitelaar JK, Faraone SV, Shaw P, Thompson PM, Franke B. Subcortical brain volume differences in participants with attention deficit hyperactivity disorder in children and adults: a cross-sectional mega-analysis. Lancet Psychiatry. 2017 Apr;4(4):310-319. doi: 10.1016/S2215-0366(17)30049-4.
• Jackson, D. B., & Vaughn, M. G. (2017). Sleep and preteen delinquency: Is the association robust to ADHD symptomatology and ADHD diagnosis? Journal of Psychopathology and Behavioral Assessment, 39(4), 585–595. https://doi.org/10.1007/s10862-017-9610-1
• Karadiamanti, A. (2021). Music therapy for children with mental illnesses. University of Western Macedonia - School of Social and Humanistic Studies - Pedagogical Department of Kindergarten (Dissertation) Thessaloniki, Greece.
• Konstantinou A. (2020). ADHD: Causes and symptoms. Panhellenic Conference of Education Sciences, 8, 620-630. https://doi.org/10.12681/edusc.2707
• Korpa, T. N. (2017). Maternal stress and daily cortisol variation in children with Attention Deficit Hyperactivity Disorder (PhD thesis).
• Kourkoutas, H., (2017). Children with Emotional and Behavioural Disorders: Clinical and Psychoeducational Interventions in the School and Family. Clinical, Educational and Behavioural Therapy, School and Family Athens: Topos.
• Landis T.D., Garcia A.M., Hart K.C., Graziano P.A. (2021). Differentiating Symptoms of ADHD in Preschoolers: The Role of Emotion Regulation and Executive Function. J. Atten. Disord. 25(9):1260–1271
• Malkoff, A. C., Grace, M., Kapke, T. L., & Gerdes, A. C. (2020). Family functioning in Latinx families of children with ADHD: the role of parental gender and acculturation. Journal of child and family studies, 29(4), 1108-1122. doi:10.1007/s10826-019-01673-5
• Maniadaki, K. & Kakuros, E. (2016). The management of ADHD. From theory to practice. Athens.
• Marcone, R., Borrone, A., & Caputo, A. (2018). Peer Interaction and social competence in childhood and early adolescence: the effects of parental behaviour, Journal of Family Studies, DOI: 10.1080/13229400.2018.1526702
• Polanczyk, G. V., G. A. Salum, L. S. Sugaya, A. Caye, and L. A. Rohde. 2015. “Annual Research Review: A Meta-analysis of the Worldwide Prevalence of Mental Disorders in Children and Adolescents.” Journal of Child Psychology and Psychiatry, and Allied Disciplines 56(3): 345–365. doi:https://doi.org/10.1111/jcpp.12381.
• Pudenz, D., Bames, A., Howard, S (2020) Social Functioning in Adolescents with  Adhd-I and Adhd-C, Brenau University ProQuest Dissertations Publishing,στο:https://www.proquest.com/openview/daf7ab70f6641db7b15f6b0a3265fa29/1?pq-origsite=gscholar&cbl=44156  
• Rydell AM, Brocki KC. ADHD symptoms and callous-unemotional traits as predictors of violent media use in adolescence. Scand J Psychol. 2021 Feb;62(1):25-33. doi: 10.1111/sjop.12693. Epub 2020 Dec 3. PMID: 33270925.
• Skaloubakas H. A guide to an individualized educational program (IEP) for students with Attention Deficit Hyperactivity Disorder (ADHD). Ministry of Education, Research & Religious Affairs. Institute for Educational Policy. Available at

• Stringaris, A. & Taylor, E. (2021). Irritability in children and adolescents, (eds.) Koumoula, A., Kotsis, K. & Dougali, A. Athens: Topos.
• Sudre G., Frederick, J., Sharp W., Takahashi, A., I., Mangalmurti, A., Shoudhury, S., Shaw P., (2020), Mapping associations between polygenic risks for childhood neuropsychiatric disorders, symptoms of attention deficit hyperactivity disorder, cognition and the brain, Molecular Psychiatry, Oct; 25 (10): 2482-2492
• Sultan, R. S., Liu, S. M., Hacker, K. A., & Olfson, M. (2021). Adolescents with Attention- Deficit/Hyperactivity Disorder: Adverse Behaviors and Comorbidity. Journal of Adolescent Health, 284-291. doi:10.1016/j.jadohealth.2020.09.036
• Ter-Stepanian, M., Grizenko, N., Cornish, K., Talwar, V., Mbekou, V., Schmitz, N., &Joober, R. (2017). Attention and Executive Function in Children Diagnosed with Attention Deficit Hyperactivity Disorder and Comorbid Disorders. Journal of the Canadian Academy of Child and Adolescent Psychiatry, 26 (1), 21-30.
• Theodoropoulos S., Kouma, Z., Lakmeta, H. (2021). Attention Deficit Hyperactivity Disorder in Student & Pupil Population. Nursing Approach. Patras. Available at http://repository.library.teiwest.gr/xmlui/bitstream/handle/123456789/9717
• Thompson PM, Andreassen OA, Arias-Vasquez A, Bearden CE, Boedhoe PS, Brouwer RM, Buckner RL, Buitelaar JK, Bulayeva KB, Cannon DM, Cohen RA, Conrod PJ, Dale AM, Deary IJ, Dennis EL, de Reus MA, Desrivieres S, Dima D, Donohoe G, Fisher SE, Fouche JP, Francks C, Frangou S, Franke B, Ganjgahi H, Garavan H, Glahn DC, Grabe HJ, Guadalupe T, Gutman BA, Hashimoto R, Hibar DP, Holland D, Hoogman M, Hulshoff Pol HE, Hosten N, Jahanshad N, Kelly S, Kochunov P, Kremen WS, Lee PH, Mackey S, Martin NG, Mazoyer B, McDonald C, Medland SE, Morey RA, Nichols TE, Paus T, Pausova Z, Schmaal L, Schumann G, Shen L, Sisodiya SM, Smit DJA, Smoller JW, Stein DJ, Stein JL, Toro R, Turner JA, van den Heuvel MP, van den Heuvel OL, van Erp TGM, van Rooij D, Veltman DJ, Walter H, Wang Y, Wardlaw JM, Whelan CD, Wright MJ, Ye J; ENIGMA Consortium. ENIGMA and the individual: Predicting factors that affect the brain in 35 countries worldwide. Neuroimage. 2017 Jan 15;145(Pt B):389-408. doi: 10.1016/j.neuroimage.2015.11.057. Epub 2015 Dec 4. PMID: 26658930; PMCID: PMC4893347.
• Thöne, A., K., Dose, C.,  Junghänel, M.,  Hautmann, C.,  Jendreizik, L., T., Treier, A., K., Vetter, P., Wirth, E., Banaschewski, T.,  Becker, K.,   Brandeis, D., Dürrwächter, U., Geissler, J., Hebebrand, J.,  Hohmann, S.,Holtmann, M., Huss, M., Jans, T., Kaiser, A., Ketter, J., Legenbauer, T., Millenet, S., Poustka, L., Renner, T., Romanos, M., Sandersleben, H., U., Schneider, P., S., Wenning, J., Ziegler, M. ,Görtz-Dorten A. & Döpfner, M. (2023). Identifying Symptoms of ADHD and Disruptive Behavior Disorders Most Strongly Associated with Functional Impairment in Children: A Symptom-Level Approach. 45, pp 277-293 στο: https://link.springer.com/article/10.1007/s10862-023-10025-z
• Thorell, L., B.,  Sjöwall, D., Diamatopoulou, S., Rydell, A., M. &  Bohlin G. Emotional functioning, ADHD symptoms, and peer problems: A longitudinal investigation of children age 6–9.5 years Infant and Child Development, 2017. Wiley Online Library
• Wiener, J., Biondic, D., Grimbos, T. et al. Parenting Stress of Parents of Adolescents with Attention-Deficit Hyperactivity Disorder. J Abnorm Child Psychol 44, 561–574 (2016). https://doi.org/10.1007/s10802-     015-0050-7
• Young S, Asherson P, Lloyd T, Absoud M, Arif M, Colley WA, Cortese S, Cubbin S, Doyle N, Morua SD, Ferreira-Lay P, Gudjonsson G, Ivens V, Jarvis C, Lewis A, Mason P, Newlove-Delgado T, Pitts M, Read H, van Rensburg K, Zoritch B, Skirrow C. Failure of Healthcare Provision for Attention-Deficit/Hyperactivity Disorder in the United Kingdom: A Consensus Statement. Front Psychiatry. 2021 Mar 19;12:649399. doi: 10.3389/fpsyt.2021.649399. PMID: 33815178; PMCID: PMC8017218. Αθήνα.

Zygouris, N. Course Notes "Introduction to Neuropsychology",