حالت، ویژگی و اضطراب و تفاوت های توجه انتخابی در زیرگروه ADHD (اختلال نقص توجه بیش فعالی)

ABSTRACT State, trait anxiety and selective attention differences in Attention Deficit Hyperactivity Disorder (ADHD) subtypes

Attention Deficit Hyperactivity Disorder (ADHD) is classified in the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, APA, 2000) into three different subtypes: a subtype with predominance of attention deficit disorder (ADHD-I), the subtype with predominance of hyperactivity-impulsivity (ADHD-HI), and the combined subtype with both attention deficit and hyperactivity-impulsivity (ADHD-C). These classification guidelines have been the subject of recurring debate concerning diagnosis of the disorder (González-Castro et al., 2013, Lemiere et al., 2010). Moreover, with the publication of the new DSM-5 classification manual (American Psychiatry Association, APA, 2013), ADHD is now categorized as neurodevelopmental disorder. While there were no significant changes in terms of the main symptoms of the disorder, with respect to classification there are now four types of presentations (instead of subtypes) of ADHD: predominantly hyperactive/impulsive; predominantly inattentive; inattentive restrictive; and combined presentation. However, regardless of the names used for classification, much research has investigated if ADHD subtypes or types of presentation differ in their development (Lahey & Willcutt, 2010), or in their epidemiology (Willcutt, 2012) and also whether different comorbidities generally associated with the disorders are dependent upon the subtype (Sciberras et al., 2014).

Some researchers note the importance of identifying comorbidity in ADHD cases, as it is an essential determining factor in the course of the disorder (Bloemsma et al., 2013, Elia et al., 2009, Humphreys et al., 2012, Rodríguez et al., 2014). Comorbidity has been reported to be associated with different disorders, such as learning difficulties, depression, oppositional defiant disorder, behavior disorders, as well as anxiety and mood disorders (González-Castro et al., 2014, Skirbekk et al., 2011). Regarding anxiety, comorbidity with ADHD is estimated at 20-25% (Bloemsma et al., 2013). The diverse estimates of the studies may be due to the extensive overlap of symptoms in these syndromes (ADHD and anxiety), so it may be difficult to determine whether a child has developed hyperactivity and inattention because of anxiety, or whether low self-esteem derived from ADHD has caused the anxious behavior. Anxious children usually display a permanent state of worry or apprehension that is difficult to control (Bloemsma et al., 2013). This can be confused with some typical symptoms of ADHD, such as restlessness, fatigue, difficulty concentrating, irritability, muscle tension, and sleep disturbance.

The relationship between ADHD and anxiety is important because, while 5% to 15% of children may suffer from an anxiety disorder, between 15% and 35% of children with ADHD display significant anxiety (Pliszka, Carlson, & Swanson, 1999). According to these authors, ADHD with comorbid anxiety may be a distinguishing feature of the subtypes, as children with ADHD and comorbid anxiety are phenotypically different from children with a pure disorder (either ADHD, or anxiety). More recently, within the Multimodal Treatment Study (MTA) for Children with ADHD, Bloemsma et al. (2013)showed that, in the group of children with ADHD and anxiety symptoms, inattention seem to prevail over impulsivity symptoms.

Children with ADHD and anxiety showed better response inhibition than pure ADHD children (Manassis, Tannock, & Barbosa, 2000). In this sense, Power, Costigan, Eiraldi and Leff (2004) also found significant differences between ADHD-C, ADHD-I, and control groups in the Behavior Assessment System for Children – Parents’ Rating Scale (BASC-PRS). Specifically, parents reported higher levels of anxiety in children with ADHD-I compared with the control group. Group differences were also found in The Revised Children’s Manifest Anxiety Scale (RCMAS), with children in the ADHD-C group showing significantly higher levels of anxiety than controls. However, Elia et al. (2009) and Mayes, Calhoun, Chase, Mink, and Stagg (2009) observed that comorbidity of ADHD with anxiety did not vary according to subtype.

The discrepancy found among different studies could, however, be related to the type of anxiety examined. In this sense, Spielberger, Gorsuch, Lushene, Vagg, and Jacobs (1983) differentiated between trait anxiety and state anxiety. Trait anxiety refers to a general level of stress that characterizes certain individuals that are often easily stressed and anxious, while state anxiety is characterized as a state of heightened emotions that appears in response to danger or fear of a particular situation. The presence of one or another type of anxiety may lead to different performance on attentional tasks (Ursache & Raver, 2013). This study showed that an increase in trait anxiety in children between 9 and 12 years was associated with lower performance in executive tasks, while an increase in state anxiety was associated with better performance. In this same direction, Sadeh and Bredemeier (2011)demonstrated that an increase in trait anxiety imposed a major distraction on selective attention tasks, an aspect of attentional control that involves the selection of the relevant stimulus stream, the suppression of the irrelevant streams, and the maintenance of attention on the relevant information (Lackner, Santesso, Dywan, Wade, & Segalowitz, 2013).

Taking into account the results of previous research, this study was aimed at verifying whether different profiles (attention and anxiety) emerge as function of ADHD subtypes. Specifically, it sought to determine whether ADHD different expressions relate to differences in selective attention and concentration (assessed using D-2 Attention task: Brickenkamp, 2001) and in the two main manifestations of anxiety (State and trait anxiety: Spielberger et al., 1983). Additionally, on the basis of the results provided by Sadeh and Bredemeier (2011) and Ursache and Raver (2013), it was also analyzed the degree to which anxiety affects ADHD students’ performance in a selective attention task.