ADHD: Combined Type
1. Meets both inattentive and hyperactive/impulsive criteria.
Additional Criteria listed in the DSM-5:
1. Some hyperactive/impulsive or inattentive symptoms that
cause impairment must have been present before ages 7-12.
2. The behaviors/symptoms have been evident for at least 6
3. Symptoms cause some impairment in two or more settings.
4. There must be clear evidence of clinical significance in
social, academic or occupational functioning.
5. Symptoms must be maladaptive and inconsistent with
individual developmental levels.
6. Symptoms are not better accounted for by another
There are many professionals who can diagnose and treat ADHD
such as pediatricians, psychiatrists, clinical psychologists and
neurologists, as well as other qualified medical and mental
health professionals. A comprehensive evaluation will usually
take place before any official diagnosis of ADHD is made. 1, 2, 3, 4
This evaluation consists of obtaining information from a variety
of sources, settings and methods to ensure the child’s diagnosis
is accurate and complete. The histories, dialogue and tests commonly utilized in the evaluation include the following:
1. Comprehensive medical and social history.
2. Interview and questionnaires with parents.
3. Behavior rating scales from school counselors, friends of
the family, child-care providers, relatives, or people close
to the child.
4. Review of school records.
5. Observations where the child spends most of their time.
6. Physical exam, sleep patterns, bedwetting (lack of control),
anxiety, depression, blood work, EEG, CT scans.
7. Performance tests to observe child’s attention span and
their ability to focus on tasks, as well as evaluate the child’s
ability to organize and pay attention to visual stimuli on
paper-pencil tasks. These are not standard tests and not
totally necessary for making the diagnosis but helpful with
8. Academic and intelligence tests help to rule out learning
disabilities. ADHD is separate from intelligence. Just
because a child has a high IQ does not mean they cannot
ADHD is a lifelong disorder which is not preventable. 1, 2, 3, 5 The
exact etiology is still unknown, but there are many research
sound theories professionals operate under. The following research based theories addressed in this course are:
2. Dopamine action
3. Abnormal brain development
The genetic theory of etiology has years of scientific backing
and evidence is quickly mounting to identify ADHD as a disorder in brain development or function with genetic origins.
Family studies have shown there is a 50% chance one parent
has ADHD when one of their offspring is diagnosed with
ADHD. 1, 3 Children with a parent or sibling with ADHD are
2-8 times more likely to develop the disorder. 6 Twin studies
have shown if one twin has symptoms of ADHD, there is a 50-
92% chance the other twin will have those same symptoms as
well (92% if the twins are identical). 1, 3
There are ongoing molecular genetic research studies, also
called “whole genome studies,” to look at entire family histories. Researchers have positively identified two genes associated with ADHD, the D4RD and DAT1.1, 3 D4RD is related
to the personality dimension known as novelty seeking. Children with ADHD are more likely to have this particular gene
which makes them display more novelty seeking behaviors in
their personality. The DAT1 gene helps to regulate dopamine
activity in the brain by influencing how quickly dopamine is
removed from the synapse. 7
Scientists are investigating at least twenty additional genes
that may make a person more vulnerable to ADHD or may
contribute to the disorder in some way. 6, 8, 9, 10, 11
Dopamine levels are believed to play a part in ADHD. Spinal
fluid samples of children with ADHD have shown decreased
levels of dopamine in some studies, but other studies using
urine samples have disagreed. 1, 2 Dopamine pathways in the
brain play a major role in human emotion, development and
overall function. Dopamine is a neurotransmitter found in the
basal ganglion of the brain. 12 It is postulated that people with
ADHD may have disturbances with their dopamine signaling
systems or a deficiency in dopamine itself. 1, 2, 3, 5, 6, 8, 9 One of dopamine’s most important functions is cognitive alertness and
vigilant concentration. 12, 13 People with ADHD have problems
in both these areas as described by the diagnostic criteria in
the DSM- 5. This is also why medications like stimulants and
non-stimulants have shown effectiveness in the management
of ADHD symptoms in many individuals. Those medications
have an effect on dopamine, as well as other neurotransmitters
and hormones in the brain, just as they do in the treatment of
other disorders including Parkinson’s and Alzheimer’s.
Abnormal brain development
Another proposed etiology of ADHD is abnormal brain development and maturation; specifically the frontal-orbital region. 14, 15
This region of the brain is responsible for inhibiting behavior,
sustaining attention, employing self-control, and planning for the
future. 6, 8 Magnetic resonance imaging (MRI) studies on children
with ADHD have found weaker brain activation in the frontal
region when responding to tasks that require inhibition. 6, 8, 14