A functional behavior assessment involves each of the following steps EXCEPT

Main Body

Abstract: This chapter defines functional assessment and describes why this approach is useful. It focuses on the methodology of functional assessment, including surveys, rating scales, observations, and experimental approaches to determine the function of behavior. The step-by-step process of functional assessment and ethical considerations will be described.

Focus Questions:

  • What is functional assessment?
  • What are the three main functional assessment approaches and how are they used?
  • What are the advantages and disadvantages of each approach?
  • What ethical considerations are necessary when implementing functional assessment?

What is Functional Assessment?

Functional assessment (FA) refers to a variety of approaches, including indirect, observational, and experimental/functional analysis procedures (Hanley, Iwata, & McCord, 2003; Hagopian, Rooker, Jessel, & DeLeon, 2013; Iwata, Dorsey, Slifer, Bauman, & Richman, 1994; Mueller, Nkosi, & Hine, 2011). FA has been found to be useful with a wide range of behaviors and populations, such as feeding disorders (Gale, Eikeseth, & Rudrud, 2011; LaRue et al., 2011), chronic hand mouthing (Roscoe, Iwata, & Zhou, 2013), off task behavior of children in the classroom (Meyer, 1999), social avoidance (Harper, Iwata, & Camp, 2013), aggression and self-injurious behaviors (Fritz, Iwata, Hammond, Bloom, 2013), elopement (Tarbox, Wallace, &Williams, 2003), hand flapping of children (Mueller, Sterling-Turner, & Scattone, 2001), hair twirling (Deaver, Miltenberger, & Stricker, 2001), and rumination (Lyons et al., 2007). The spring 2013 issue of the Journal of Applied Behavior Analysis is devoted to FA-related research reflecting the strong empirical foundation that has contributed to the development of this approach. Furthermore, FA is a relatively versatile approach that, following instruction, has been implemented by parents (Gale, Eikeseth, & Rudrud, 2011; Shayne & Miltenberger, 2013), students (Iwata et al., 2000), teachers (Wallace, Doney, Mintz-Resudek, & Tarbox, 2004), and staff (Moore & Fisher, 2007).

The main reason for conducting a FA is to identify the possible causes of an individual’s challenging behavior so that an effective treatment can be designed (Chander & Dahlquist, 2010). Identification of the variables maintaining the challenging behavior prior to designing treatment is necessary since certain treatments can be contra-indicated or ineffective, depending on the function of the behavior (Iwata, Pace, Cowdery, & Miltenberger, 1994; Newcomer & Lewis, 2004).

Other reasons for using a FA include that it:

  • Is required by federal law (IDEIA, 2004)
  • May provide convincing evidence for treatment team decision-making and provide accountability
  • May result in less use of a punishment procedure (Pelios, Morren, Tesch, & Axelrod,1999)
  • Is recommended by professional associations (National American School Psychologists)

A FA approach is used to gather data regarding why the individual’s challenging behavior is occurring. Challenging behaviors may serve a purpose or function for the individual and are often a function of environmental conditions (Hanley, 2012). After the reinforcers maintaining the individual’s challenging behavior are clearly identified, it should be possible to predict the circumstances under which the behavior is likely to happen and what is causing it to recur. The motivating conditions and antecedents for the individual’s challenging behavior may be altered to decrease that behavior. For example, if Mary cries and hits herself due to fatigue when her bedtime approaches, then an earlier bedtime can be arranged. Similarly, Darrell’s hitting and screaming for candy at the grocery store may be prevented by bringing some of his favorite snack on the shopping trip and keeping the trip short. Additionally, more appropriate behaviors that achieve the same result may be taught, called functional replacement behavior. For example, Nija’s crying when she wants her doll can be decreased by teaching her to make the sign for doll in situations where she cried to get it in the past. To decrease the likelihood that Caden runs out of the classroom when reading class begins (a difficult skill for Caden), his teacher provides additional one-on-one instruction to establish his reading skills.

A functional behavior assessment involves each of the following steps EXCEPT
Figure 1. The Functional Assessment Process.

FA Methodology

There are three main categories of functional assessment approaches—indirect (e.g., questionnaires, rating scales), observational, and experimental/functional analysis. Gathering information about the conditions surrounding the behavior, asking relevant individuals questions about the behavior are initial steps. If the results of indirect and observational assessment are unclear, testing the possible maintaining variables for the individual’s challenging behavior would next be performed. See Figure 1 of the FA process for an outline of this overall way to proceed when addressing the individual’s challenging behavior.

Indirect Functional Assessments

An indirect functional assessment is a procedure in which information about the challenging behavior is gathered from persons who are closest to the individual, such as parent(s), teachers, service providers, and aides. Rating scales, questionnaires, and interviews are used to gather information on potential factors that contribute to the individual’s challenging behavior (e.g., O’Neill et al., 1997). One example of an indirect assessment method is the Functional Analysis Screening Tool (FAST). The FAST is a 16-item questionnaire that can be administered to individuals who know the person with challenging behavior well to identify antecedents and consequences correlated with the behavior (Iwata, DeLeon, & Roscoe, 2013).

When using an open-ended FA interview, persons who are the closest to the individual with challenging behaviors are asked to describe in detail the circumstances occurring before and after the challenging behavior, the conditions under which it occurs most and least, its characteristics, and more (Hanley, 2012; O’Neill et al., 1997). Correlated variables noted from the information gathered during the interview can then be further examined with other types of FA. Additionally, an indirect functional assessment may be helpful with initially defining the challenging behavior since the relevant individuals are asked to describe exactly what the individual does when performing the challenging behavior.

There are limitations of using an indirect FA. Since the type of data gathered with indirect methods is not based on objective direct observation, it may be laced with differing perspectives and subjective viewpoints and be prone to memory errors. For example, interview data can provide much information, but can also be biased. A parent may relay during an interview that her child’s challenging behavior only “occurs when his dad is taking care of him.” In this example, the parent seems to identify the father as part of the problem. In a recent study, Iwata et al. (2013) found that reliability, or the agreement between raters, using the FAST was 71.5%. The validity of the FAST, or an outcome comparison of FAST to an experimental analysis of behavior, was found to be 63.8% across 69 cases. These results suggest that although indirect methods, such as the FAST, can be a quick means of obtaining preliminary information about the nature of the individual’s challenging behavior, additional corroborating evidence about the function of the behavior is necessary. This additional evidence may be obtained by the therapist or teacher conducting an observational FA.

Observational Functional Assessment

In an observational functional assessment, the professional directly and unobtrusively observes the individual’s challenging behavior in the natural environment, and records the circumstances surrounding the behavior (Lalli, Browder, Mace, & Brown, 1993). One method of collecting observational assessment information is to use a time chart, where a mark is made in the appropriate cell to indicate the time period and day in which a particular behavior was observed (Touchette, MacDonald, & Langer, 1985). From this information, certain activities, events or people correlated with the occurrence of the challenging behavior can be identified as possible causes of that behavior. For example, as seen in Table 6 below, if it is found that Sally consistently runs around and screams at 10 am, then the activity and conditions that usually occur at that time, say, during spelling, can be explored as somehow being associated with her behavior (e.g., difficult, noisy, boring, peer attention) and possibly contributing to it.

Table 6: Example of Time Chart Data Sheet
M T W Th F S S
9:00 X
10:00 X X X
11:00 X X
X = at least one instance of the behavior

Data is collected on the antecedents, behavior, and consequences (the ABCs of behavior) as they unfold in the situation where the challenging behavior most often occurs. This procedure of writing down in as much detail and objective a manner as possible is called ABC functional assessment. An ABC functional assessment often takes place in multiple settings or under different conditions (e.g., during math, language, or physical education instruction) so as to provide similar and contrasting information about the situations where the challenging behaviors are likely to occur. The degree of consistency in co-occurrence of certain antecedents and/or consequences with the challenging behavior across 30-60-min sessions held across 5 or more days is analyzed. These data may also serve as baseline information to compare the effects of later implementation of treatments to decrease the individual’s challenging behavior. Teachers, families, or staff may record the circumstances surrounding the individual’s challenging behavior. For instance, Annette may scream when adults around her are talking and when she does this, an adult typically asks her to be quiet. Examples of antecedents within the learning environment may include instructional content, teacher proximity, and peer interactions. Positive reinforcers for the challenging behavior may include certain language, gestures, removal of demands, physical touch, or eye contact by teachers or other students. See Table 7 for an example of an ABC recording data sheet.

Table 7: Example of ABC Recording Data Sheet
Client: Barbara Beam
Situation: Special education class. Picture naming task with teacher’s assistant (TA)
Observer: Therapist
People Present: 15 other students, teacher, TA
Time  Antecedent Behavior Consequence
1:30 pm TA hold up picture & “What’s this?” “hoose” “Good, Barbara, that’s it: horse.”
1:45 pm Picture of flower presented “What’s this?” “hoose” “No, it’s a flower”
Flower & “What’s this?” No response “Flower, say flower”
Flower & “What’s this?” Cry, flap hands “Quiet, Barbara”
Flower & “What’s this?” Grab card & rips it while screaming and flapping hands “Barbara, no!”

1:52 pm

Slowly stops crying, sitting quietly, finger flicking

A direct observational FA can provide an objective means of gathering information that may help to substantiate indirect assessment findings. The data generated from an ABC recording procedure can be subjected to a conditional probability analysis of the correlated observed antecedent and consequence events to determine which events are most likely to be associated with the challenging behavior (e.g., frequency of X antecedent co-occurring with behavior divided by the total number of times X occurred multiplied by 100). However, it should be recognized that observational methods are correlational and so causal conclusions are not possible. There may be other factors involved in contributing to the occurrence of the individual’s challenging behavior that are involved and have not been identified.

Functional Analysis (FAn)

Functional Analysis involves an experimental test of the different possible functions for the client’s problem behavior (e.g., attention positive reinforcement, tangible positive reinforcement, demand/negative reinforcement). FAn has been established as a clinically effective method of identifying the function of challenging behavior and treating it based on several decades of accumulated research (Beavers, Iwata, & Lerman, 2013). Using a standard FAn, attention, demand, tangible, and alone conditions are compared to a play/recreational control condition (e.g., Iwata, Dorsey, Slifer, Bauman, & Richman, 1982/1994).

The attention condition is conducted to determine if the individual’s problem behavior is due to attention positive reinforcement. Under conditions of social deprivation and in the presence of one or two adults, eye contact, physical contact, reprimands, and verbal interaction “No, don’t do that” or similar comments that typically are given by others in the individual’s natural environment are delivered immediately after the individual’s challenging behavior. Note that this condition may be tailored to the specific stimuli found to correlate with the occurrence of the individual’s challenging behavior based on indirect and observational FA.

The demand condition is conducted to determine if the individual’s problem behavior is due to escape/avoidance of task demands or activities (i.e., negative reinforcement). The therapist or teacher presents an activity or instruction to complete a task that the individual has in the past (based on interview or observational data) had difficulty in completing even when physically guided to do so. If the individual engages in the challenging behavior at any time, then the therapist immediately turns away from the client for 30 s.

The tangible condition is conducted to evaluate whether tangible positive reinforcement is maintaining the individual’s challenging behavior. Based on information gathered from other assessments (e.g., indirect, observational), preferred objects are placed out of reach (e.g., on a shelf). When the individual engages in the challenging behavior, that preferred item is delivered for 30 s.

In the alone condition, the client is in a room by him/herself with no toys or activities. Note that, as is the case in each of these conditions, all safety concerns should be addressed and appropriate precautions taken. The therapist observes the client’s behavior for the purpose of data collection from a one-way mirror or video camera. This condition involves a situation in which low levels of stimulation are present in order to test whether self-stimulation or automatic reinforcement is maintaining the client’s problem behavior. The client is placed in the therapy room alone, without any toys or materials that would provide a source of stimulation.

In the play condition, toys or activities are presented and the therapist interacts socially with the client. This condition serves as a comparison or control condition to rule out confounding variables such as the challenging behavior due to variables present in the attention, tangible, or demand conditions (e.g., the presence of the therapist, materials, social interaction). The therapist and client are in a room with a variety of toys or leisure activities present. The therapist provides social praise and brief physical contact contingent on the client’s appropriate behavior at least once every 30 s.

Evidence regarding the function of that behavior is provided when levels of the challenging behavior are higher in one condition compared to the other conditions. For instance, if the level of client’s behavior is consistently (e.g., across 5 sessions or more) greater in the demand condition than that in the other conditions, the function of the challenging behavior would be negative reinforcement. See Chapter 6 for additional information about FAn and a description of the conditions.

Research Design & Functional Analysis

A FAn compares the effects of various conditions using single participant experimental research designs. Commonly used research designs when conducting FAn include multielement and ABAB designs as defined below. The duration of presentation of each condition is typically at least 5 min with a brief (e.g., 5-min) break between conditions if several are presented on one day.

When implementing an ABAB Research Design, or a reversal-replication research design, the first step involves measuring the dependent variable (the individual’s challenging behavior) during the baseline phase (A), when no treatment is applied (Martin & Pear, 2011). Once stability of the behavior has been achieved, the treatment or the independent variable (B) is applied and its effect on behavior is observed. Lastly, these two phases are repeated or replicated. A convincing demonstration of the effect of the independent variable on the dependent variable is provided if the behavior changes only when treatment is present and not when it is absent. In other variations of this design different treatment conditions can be compared as opposed to including a baseline comparison.

In the graphed data presented in Figure 2 below, the use of an ABAB research design in a FAn to test the effects of easy versus difficult school work on the off-task behavior of a child in the classroom is illustrated. The levels of off-task behavior are greater when difficult school work is presented compared to when easy school work is presented. Intervention can be designed to provide the child with greater assistance or teach the child to ask for assistance when difficult school work is given.

A functional behavior assessment involves each of the following steps EXCEPT
Figure 2. An example of an ABAB research design to test the effects of easy versus difficult school work on the off-task behavior with one child.

With a multielement research design two or more conditions or treatments (i.e., independent variable) are alternated rapidly (e.g., treatments A and B are conducted in one day or during the same hour). This design is also known as alternating treatment or simultaneous treatment research design (Martin & Pear, 2011). The conditions are alternated across days (e.g., Day 1: attention, demands, alone, play; Day 2: demands, alone, play, attention, etc.) to reduce the confounding effects of order. Like an ABAB research design, the purpose of the multielement research design is to determine which of several conditions or treatments produce a change in the behavior of interest. The difference in levels of the challenging behavior between conditions is evaluated to determine which condition affects the behavior most. In the following graphical presentation of FAn seen in Figure 3, the frequency of aggressive behavior is highest in the attention condition compared to the other conditions providing experimental evidence that attention positive reinforcement is maintaining the individual’s aggressive behavior.

A functional behavior assessment involves each of the following steps EXCEPT
Figure 3. An example of a multielement research design to determine the effects of attention, demands, play, and tangible conditions on an individual’s frequency of aggressive behavior.

The following is an example of the steps involved in conducting an example of a functional analysis procedure using a multielement research design:

  • Define the problem behavior.
  • In a controlled setting, present 10 min where the attention condition is in effect and instances of the problem behavior are recorded.
  • 5 min break.
  • Present 10 min of the demand condition
  • 5 min break
  • Present 10 min play condition
  • 5 min break
  • Present 10 min of alone condition
  • On day 2, repeat above with randomized order of conditions.
  • Repeat for 3 more days or more depending on the stability of the data

Data Analysis

At least five data points are collected for each condition so that trends, levels of the problem behavior, and non-overlapping data points across conditions can be compared. Graphed data are examined to identify differential levels of the individual’s behavior across conditions. The data patterns are analyzed by examining stability, trends, overlapping data points, and magnitude of effect observed for the test conditions compared to the control (play/recreation) condition (Martin & Pear, 2011). If variability in the data pattern and/or overlapping data patterns are observed, then additional sessions may need to be conducted until stability and differentiation of the levels of behavior in each condition is reached to allow an interpretation of the results (see Bourret & Pietras, 2013 for more).

Advantages and Disadvantages of FAn

Like the other FA methods, there can be advantages and disadvantages to using a functional analysis approach. The major advantage of FAn is that it provides the most accurate information about the function of the individual’s behavior (Floyd, Phaneuf, & Wilcynski, 2005; Iwata et al., 2013). FAn is the only method that yields a “cause and effect” interpretation of the findings. Since this approach uses an experimental method that involves manipulating conditions (attention, alone, demand, or demand conditions) while controlling or holding constant other potentially confounding factors (play condition), the results from a FAn can be used to identify the specific factors maintaining the problem behavior. In a comparison of indirect, observational, and FAn methods to identify the function of the challenging behavior of seven children with autism, Tarbox et al. (2009) found that indirect and FAn methods produced more conclusive findings for all seven children than an observational method did. In contrast, Alter, Conroy, Mancil, and Haydon (2008) found one-to-one correspondence between FA observational methods and FAn and less correspondence with indirect FAn methods when identifying the function of challenging behavior with four young males. Additionally, in Taylor and Romanczyk’s (1994) study, the functions of students’ challenging behavior based on observations of teacher’s interaction with their students in the classroom predicted experimentally verified functions of those behaviors.

There are notable limitations to using a FAn. When the problem is multiply determined or low rates of occurrence of the challenging behavior exist, then interpretation of the results of a functional analysis may be difficult. Another disadvantage is that the function of the challenging behavior may not always be readily identified using the standard functional analysis conditions (i.e., attention, tangible, demand, control). In which case, tailoring the conditions used in a functional analysis to the individual’s circumstances may be necessary. Hapopian et al. (2013) describe how the maintaining variables for over 90% of 176 inpatient cases of individuals with intellectual disability and severe challenging behaviors were identified as a result of conducting a series of more individually-tailored or idiosyncratic FAn.

Researchers have attempted to address the difficulties with conducting FAn, such as the ethical issues when targeting harmful behaviors (Hanley, 2012). As one approach, procedures may be modified to reduce the threat of harm to the individual due to provocation of the challenging behavior during the assessment conditions. For instance, conditions may be a single trial (rather than 5-min sessions) and embedded in naturally-occurring ongoing activities in the individual’s environment (Bloom et al., 2011; Bloom, Lambert, Dayton, & Samaha, 2013). Other approaches entail measuring precursor behaviors instead of the actual challenging behavior (Fritz et al., 2013) or latency to engage in the challenging behavior (Neidert et al., 2013). A summary of the different types of FA and their advantages and disadvantages can be seen in the Table 8 below.

Table 8: A summary of the different types of FA and their advantages and disadvantages
Types of FA Description Advantages Disadvantages
Indirect Interviews, rating scales, surveys A lot of information, quick Bias


Not causal information

Not as accurate as FAn

Observational ABC observations; Time charts Possible causes identified; observing behavior may generate ideas about functions of behavior Correlational information

Not as accurate as FAn

May miss important variables

Low rate behaviors may be difficult to observe

Functional Analysis (FAn) Experimentally testing relevant conditions (play, demands, attention, tangible, alone) Clear cause of behavior may be identified Can be unethical to conduct if the behavior is severe and harm may occur

May not discover cause if multiple variables exist

Must be extended across days if low frequency behaviors

Multiple treatment interference or carry over effects with multielement designs

The data may be incorrectly interpreted

May neglect other relevant variables (physiological, idiosyncratic variables)

Family Contribution to Assessment of the Individual’s Challenging Behavior

Families play an essential role in providing necessary information for early detection and diagnosis, assessment, and are often involved in implementing interventions (Friend & Cook, 2007). Early detection followed by intervention provides the best chance of long-term beneficial outcomes for children with challenging behaviors (Shapiro & Batshaw, 2013). Understanding the family and their culture is necessary when assessing an individual’s challenging behavior. Cultural differences may involve any combination of age, race/ethnicity, social class, sex, language, religion, sexual orientation, ableness (special needs), regionality, and nationality. For instance, a family may come from cultural contexts with very different viewpoints about education and appropriate child behaviors and this may be involved with the occurrence of the individual’s challenging behaviors. The more different the cultural background of the family, the more likely that the individuals involved will face cultural conflicts resulting from those differences (Brown, 2010). This is especially true when sensitive topics or cultural incidents occur. Understanding the family and the cultural context of the family is critical to a comprehensive assessment and treatment. Professionals must ensure that families are part of the process and strive to build a positive, strong partnership with the family.

Ethical Considerations

A number of ethical issues should be considered before undertaking an FA. Ethical principles or procedures refer to rules that professions or organizations have specified to ensure survival of the culture (Skinner, 1953). Abiding by ethical considerations protects the client and others and can contribute to high quality care for the person. The overarching ethical considerations are: do no harm, right to privacy, and informed consent. Several federal laws mandate assessment, evaluation, and interventions with persons with disabilities, including Individuals with Disabilities Education Act, Americans with Disabilities Act, the Buckley Amendment of Families Equal Right to Privacy Act (FERPA) and other state and local policies. Professionals should be well-versed about these laws and policies and act accordingly. Other ethical factors specific to the FA process include: informed consent from the individual and family to perform FA and determine acceptability of treatment procedures, competence of the professional, adequate and appropriate behavior measures of baseline, treatment, and post-treatment to allow objective and fair evaluation of treatment effectiveness, the choice of a least restrictive alternative or intervention path, and the right to effective treatment based on research based intervention practices. Table 9 lists professional organizations in psychology and education that describe ethical guidelines, principles, and procedures.

Table 9: Ethical guidelines, principles, and procedures by organizations or associations


American Psychological Association

Behavior Analyst Certification Board (2010) Guidelines for Responsible Conduct for Behavior Analysts.


CEC 2001 Content Standards, Standard 3 Council for Exceptional Children. (2009). What every special educator must know: Ethics, standards, and guidelines (6th ed.).

According to Friend and Cook (2007), all assessment procedures must meet the following ethical guidelines:

  • Must be nondiscriminatory on a racial, cultural, and linguistic basis.
  • Instruments must be valid and reliable.
  • Administration is by trained professionals.
  • Testing format must take into account possible impact of the suspected disability.
  • Testing must be in the language with which child is most comfortable.
  • Include a variety of assessment tools and techniques.

Discussion Questions

  1. What are the basic tenets of an FA approach?
  2. What are the three ways in which FA can be conducted? What are their advantages and disadvantages? When would you use one or the other types of FA?
  3. Speculate about the possible difficulties involved in evaluating challenging behavior.
  4. How can competency in performing FAs be established with college students who are entering professions where they may work with individuals with challenging behavior?
  5. What are important ethical considerations when assessing and treating the challenging behaviors of individuals with developmental disabilities?

Exercise 1: Case Study Simulation

Jimmy is a fifth grade student who has been in and out of five foster homes over the course of his life. Jimmy does not have many friends, due in part to his frequent transitions to new schools and homes. Jimmy is currently placed with a loving older couple who want to stabilize his daily life. Jimmy is very quiet and shy, often described as sullen by previous teachers. He participates in noxious behaviors, such as vomiting and spitting, when asked to complete a task that he doesn’t like or want to do. Using the approaches described in this chapter, evaluate Jimmy’s problem behavior by answering the following questions:

  1. Propose a behavioral definition for Jimmy’s challenging behaviors. Ad lib as needed.
  2. How would you begin to investigate the reasons for this behavior?
  3. What indirect methods of FA could be used to evaluate this problem behavior?
  4. What questions would you ask of the adults who are most significant in Jimmy’s life?
  5. What might be a plausible maintaining variable for Jimmy’s challenging behavior?
  6. Plan how you would conduct a FAn to determine if your hypothesis for the function of Jimmy’s challenging behavior is correct. Draw a graph that depicts the results of a FAn that illustrates that function.
  7. Which type of FA method would provide you with the best evidence concerning the function of Jimmy’s challenging behavior?
  8. What ethical issues are involved with assessment and treatment of Jimmy’s behavior?

Exercise 2: Interpreting Functional Analysis

Search for a research article in the library’s databases that involves use of functional analysis and treatment effectiveness evaluation and complete the following:

  1. Write an APA-style reference
  2. Describe the client and general background
  3. Behaviorally define the target behavior
  4. Summarize the functional analysis conditions
  5. Describe the functional analysis graphed results
  6. Identify the maintaining variable for the client’s problem behavior
  7. Identify effective treatments and explain how knowledge of functional analysis led to that design.
  8. Summarize what ethical procedures were used in the study.

Which of the following statements is true about the causes of EBD?

Which of the following statements is true about the causes of​ EBD? There is no single​ cause, but biological and environmental risk factors contribute to it.

What is EBD?

EBD is an emotional disorder characterized by excesses, deficits or disturbances of behavior. The child's difficulty is emotionally based and cannot be adequately explained by intellectual, cultural, sensory general health factors, or other additional exclusionary factors. Eligibility and Placement.

What are two broad dimensions of behavior disorders?

Two broad dimensions of behavior disorders are externalizing and internalizing.

What percentage of students with learning disabilities also are identified as ADHD?

Many children with ADHD – approximately 20 to 30 percent – also have a specific learning disability. The principle characteristics of ADHD are inattention, hyperactivity, and impulsivity. There are three subtypes of ADHD recognized by professionals.