Developmental Disorders and Mental Health Disorders

1. Developmental disorders and mental health disorders

According to the United Nations Convention on the Rights of Persons with Disabilities (Act on the Ratification of the Convention on the Rights of Persons with Disabilities and the Optional Protocol to the Convention on the Rights of Persons with Disabilities, Official Gazette 6/2007), persons with disabilities are individuals who have long-term physical, mental, intellectual or sensory impairments which, in interaction with various barriers, may hinder their full and effective participation in society on an equal basis with others.

Developmental disorders (neurodevelopmental disorders) have a neurological basis and may interfere with the acquisition, retention, or application of specific skills or sets of information. They may include impairments in attention, memory, perception, language, problem-solving, or social interactions. Such disorders can be mild and easily managed with behavioural and modified educational approaches, or they can be more severe, requiring greater support for affected children (Sulkes, n.d.).

Mental health disorders are characterised by significant disruptions in an individual's mental activity, emotional regulation, and social adjustment behaviours. They are typically associated with distress or impairment in important areas of functioning (Singh, n.d.).

This lesson will present some characteristics of motor disorders and chronic diseases, specific learning difficulties, attention deficit hyperactivity disorder (ADHD), autism spectrum disorders, visual and hearing impairments, and mental health disorders.

2. Motor disorders

3. Chronic diseases

The basic characteristics of individuals with chronic diseases are:

1. The presence of a disease that is permanent, varies in severity, and requires long-term treatment.
2. Variability in health status throughout the year.
3. A disease affecting one system can negatively impact the functions of other systems.

Examples of chronic diseases include:

• Cardiovascular diseases
• Malignant diseases
• Metabolic system diseases (diabetes mellitus)
• Respiratory system diseases (chronic obstructive pulmonary disease, chronic bronchitis, asthma)
• Endocrinological system diseases (thyroid disease)
• Neurological diseases (epilepsy)
• Digestive system diseases (Crohn's disease)
• Rare diseases

4. Specific Learning Disabilities

5. Attention-Deficit/Hyperactivity Disorder (ADHD)

Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common neurodevelopmental disorders in childhood and adolescence (Jurin & Sekušak-Galešev, 2008). The DSM-5 introduced updated criteria, extending the age limit for the onset of symptoms to twelve years (Vitola et al., 2017). ADHD can also be diagnosed in adulthood, which may indicate that symptoms were present in childhood but were overlooked (Jurin & Sekušak-Galešev, 2008).

The DSM-5 (2013, as cited in Klarić, 2022) defines the criteria for diagnosing ADHD:

Inattention: Six or more of the following symptoms must have persisted for at least six months to a degree that is inconsistent with the developmental level and directly impacts social and academic or occupational activities:

• fails to give close attention to details, overlooks them, or makes careless mistakes in work tasks or other activities
• has difficulty sustaining attention during tasks (e.g., maintaining focus during lectures, conversations, or lengthy reading)
• often does not seem to listen when spoken to directly (appears as if the mind is elsewhere, even without obvious distractions)
• often does not follow through on instructions and fails to finish tasks (starts a task but quickly loses focus and is easily sidetracked)
• has difficulty organising tasks and activities (e.g., difficulty managing sequential tasks, keeping materials and belongings in order, messy or disorganised work, poor time management, failure to meet deadlines)
• often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort (e.g., preparing long documents or reports)
• frequently loses things necessary for tasks or activities (e.g., wallets, keys, glasses, mobile phones)
• is easily distracted by extraneous stimuli (in adults, this may include unrelated thoughts) or forgetful in daily activities (e.g., performing household chores, paying bills, returning calls).

Hyperactivity and Impulsivity: Six or more of the following symptoms must have persisted for at least six months to a degree that is inconsistent with the developmental level and directly impacts social and academic or occupational activities:

• often fidgets with or taps hands or feet, often leaves their seat in situations where remaining seated is expected 
• experiences feelings of restlessness
• unable to engage in leisure activities quietly, is often 'on the go'
• feeling uncomfortable being still for extended periods
• talks excessively
• blurts out an answer before a question has been completed (e.g., completes other people's sentences)
• has difficulty waiting for their turn
• interrupts or intrudes on others, butts into conversations or activities, or may start using other people's things without permission.

6. Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) reflects neurological diversity among human differences. It is a variable neurological condition that affects brain structure and the way the brain perceives and processes stimuli, differing from the majority of people, with consequences in social, emotional, and occupational contexts.

According to the DSM-5 (2013), two key criteria are identified:

1. deficits in social communication and
2. social interaction restricted, repetitive patterns of behaviour, interests, and activities

The DSM-5 consolidates the terms autism, pervasive developmental disorder, Asperger’s syndrome, and childhood disintegrative disorder under the single term Autism Spectrum Disorder. This change has made the boundaries of the disorder less clearly defined. As it is a spectrum, there are two ends of a continuum – high-functioning and low-functioning autism (Aguila Munoz, 2020).

7. Visual Impairments

Visual impairment refers to any vision condition that makes it difficult to perform daily activities that rely on visual perception. Visual perception is the ability to interpret the surrounding environment based on visual information. It is defined by visual acuity and the visual field. Visual acuity is the eye's ability to discern fine details and clearly see two separate points. The visual field is the area visible while looking straight ahead without moving the head or eyes. Based on severity, visual impairments are classified as low vision or blindness.

• Low vision (sometimes associated with amblyopia) includes visual acuity ranging from 10 % to 40 % of normal vision in the better eye with corrective lenses (glasses or contact lenses). It also includes visual acuity greater than 40 % if the condition is progressive, or less than 10 % if the person is able to use that vision effectively.
• Blindness refers to visual acuity of less than 5 % of normal vision in the better eye with corrective lenses. It also includes cases where central vision is less than 25 % of normal acuity, accompanied by a visual field reduced to less than 20 degrees.

A visual impairment does not necessarily result in deviations in emotional or social development; however, real barriers do exist. Limitations in visual observation and tracking lead to limitations in visual learning. A lack of visual information can cause delays in cognitive development. Individuals with low vision read standard print (inkprint) that is enlarged according to their needs. Blind individuals read Braille, and their success depends on intellectual development, fingertip sensitivity, motor dexterity, teaching methods, and practice. Motor development is affected not so much by the visual impairment itself, but by the inability to practise and visually imitate the movements and actions of others. Communication and socialisation are also made more difficult (URIHO, Visual Impairments).

Colour blindness is a condition that affects a person's ability to distinguish certain colours. People with this disorder most often have difficulty distinguishing specific shades. The condition is hereditary and affects men (about 8 %) significantly more often than women (about 0.5 %). Each eye has three types of photoreceptors (cones) that activate in various combinations to enable colour perception: receptors for red, green, and blue. In colour blindness, one or more of these receptors do not function correctly, leading to problems distinguishing certain colours.

There are different types of colour blindness depending on which photoreceptor is affected:

• Deuteranopia: The most common form; individuals have difficulty recognising green and often confuse it with red.
• Protanopia: Individuals have difficulty recognising red and often confuse it with green.
• Tritanopia: The rarest form; individuals have difficulty recognising blue and may confuse it with yellow.
• Monochromacy: An extremely rare condition in which a person cannot recognise any colours and sees the world exclusively in shades of grey.

8. Hearing Impairment

Hearing impairment refers to the inability or reduced capacity to receive, conduct, or register auditory stimuli. The function of any specific anatomical part of the auditory system may be compromised due to damage, underdevelopment, or disease.

Hearing is classified into three categories:

• Normal hearing – the hearing threshold for normal sound ranges from 0 to 25 dB.
• Hard of hearing – this category begins above 25 dB and includes mild, moderate, and severe hearing loss up to 90 dB.
• Deafness – any threshold above 90 dB is classified as deafness.

The term 'deafness' is a technical term usually associated with a specific residual level of hearing, where the impairment cannot be overcome solely by using a hearing aid. True (clinical) deafness, which implies no residual hearing in any form, is very rare (URIHO, Hearing Impairments).

9. Mental Health Disorders

Mental health disorders are relatively prevalent. They often begin in young adulthood, follow a chronic course, reduce quality of life and contribute significantly to healthcare resource consumption. Due to their significance and scale, mental disorders in Croatia, as well as globally, represent one of the priority public health challenges (Brkić Miloš, 2025).

10. Depression

Depression is a mental health disorder in which feelings of sadness and apathy become dominant and pervasive, affecting nearly all areas of life by reducing the ability to perform various activities and enjoy life. Symptoms of depression affect mood, emotions, patterns of thought, behavior, and physical functioning.

Typical symptoms of depression include:

• depressed mood

• loss of interest and pleasure in previously enjoyable activities (anhedonia)

• decreased vital energy

• fatigue

• physical symptoms: chest pressure, abdominal discomfort, restlessness, insomnia, digestive and appetite problems

• sleep disturbances: difficulty falling asleep, frequent or early awakening

• poor concentration and forgetfulness

• frequent pessimistic thoughts

• thoughts about the meaning of life and suicide (suicidal ideation)

• reduced self-confidence

• feelings of guilt and worthlessness.

The prevalence of depression in the population ranges from 5 % to 10 %, while the estimated lifetime risk of developing the disorder is 20 % to 30 %. Women are twice as likely to suffer from depression as men.

Depression occurs as a result of an interaction between:

• biological vulnerability (genetic predisposition)

• psychological vulnerability (difficulties coping with stressors, low self-esteem, tendency toward idealization)

• social factors (stressful life events such as job loss and financial difficulties).

Treatment involves a combination of medication and psychotherapy (HZJZ, 2011a).

11. Anxiety

12. References

Aguila Munoz, S. (2020). A Student with Asperger’s Syndrome.

Brkić Miloš, I. (Ed.) (2025).Mental Disorders in the Republic of Croatia. Croatian Institute of Public Health (HZJZ).

Horvatić, S. (Ed.) (2010). Instructions for the Adaptation of Examination Technology for State Matura Exams. National Center for External Evaluation of Education (NCVVO).

HZJZ (2011a). Depression. Ministry of Health and Social Welfare of the Republic of Croatia, Croatian Institute of Public Health: Department for Epidemiology of Chronic Mass Diseases.

HZJZ (2011b). Anxiety. Ministry of Health and Social Welfare of the Republic of Croatia, Croatian Institute of Public Health: Department for Epidemiology of Chronic Mass Diseases.

Jokić-Begić, N., Jureša, V., Živčić Bećirević, I., Čuržik, D., Drusany, D., Musil, V. (2015). Guidelines for Dealing with Students with Mental Health Issues and Chronic Diseases within the Academic Environment. University of Zagreb.

Jurin, M. & Sekušak-Galešev, S. (2008). Attention Deficit Hyperactivity Disorder (ADHD) – A Multimodal Approach. Paediatria Croatica, 52(3), 195-201.

Klarić, I. (2022). Attention Deficit Hyperactivity Disorder (ADHD) and Romantic Relationships. Graduate Thesis (Mentor: Cvitković, D.). University of Zagreb, Faculty of Education and Rehabilitation Sciences.

Logoped.hr. (n.d.). Specific Learning Difficulties (Dyslexia, Dysgraphia, and Dyscalculia).

Pinjatela, R., Ivošević, M., Stjepanović, I., Ivanković, A. (2015). Motor Disorders and Chronic Diseases. Course Material. University of Zagreb, Faculty of Education and Rehabilitation Sciences.

Rubin, M. (n.d.). Overview of Peripheral Nervous System Disorders. HeMED.

Singh, N. (n.d.). Basic Guide to Mental Health.

University of Zagreb (n.d.). Guidelines for Equalizing Study Opportunities for Persons with Dyslexia.

Sulkes, S.B. (n.d.). Definition of Developmental Disorders.

URIHO (n.d.). Hearing Impairments. In Curriculum for Professional Development: "Training on Methods and Techniques for Teaching Persons with Disabilities in Informal Adult Education".

URIHO (n.d.). Visual Impairments. In Curriculum for Professional Development: "Training on Methods and Techniques for Teaching Persons with Disabilities in Informal Adult Education".

Vitola, E. S., et al. (2017). Exploring DSM-5 ADHD criteria beyond young adulthood: phenomenology, psychometric properties and prevalence in a large three-decade birth cohort. Psychological Medicine, 47(4), 744–754. https://doi.org/10.1017/S0033291716002853 

Act on the Ratification of the Convention on the Rights of Persons with Disabilities and the Optional Protocol to the Convention on the Rights of Persons with Disabilities. Official Gazette 6/2007.