Concurrent anxiety symptoms in attention-deficit/hyperactivity disorder symptoms related to adolescent delinquency, aggression and commitment of violent acts
Jens Biteus & Michaela Tuiskunen Örebro University
Supervisor: Selma Salihović Psychology III
Abstract
The current study aimed to examine subgroups with different levels of attention deficit/hyperactivity disorder-symptoms and anxiety symptoms and how these differed regarding involvement in delinquent behavior, aggression and commitment of violent acts. We hypothesized that four subgroups would be identified, and the subgroup with high levels of both ADHD and anxiety symptoms would report equal levels on total delinquency as adolescents with ADHD only and that it would be mostly common among adolescent boys with ADHD to have concurrent anxiety symptoms. We also hypothesized that symptoms of hyperactivity/impulsivity would be more related to the predicted outcomes than symptoms of inattention. The study was conducted through self-reports of 1072 adolescent boys and girls from a community-based sample in Sweden. The results of the k-mean cluster analysis revealed four different subgroups with different levels of ADHD and anxiety symptoms, labeled ADHD-anxiety, ADHD-only, anxiety-only and non-symptom. Further, one-way Analysis of Variance (ANOVA) revealed that the ADHD-only subgroup reported
significantly higher on total delinquency and aggression than the other subgroups. ADHD-anxiety subgroup reported significantly higher on minor property offenses and commitment of violent acts. 2x4 Factorial ANOVA revealed that anxiety were more common among
adolescent boys. Thus, inattention was found to be more strongly related to the predicted outcomes than symptoms of hyperactivity/impulsivity. These findings suggest that adolescents with concurrent ADHD and anxiety might need different intervention and treatment approaches.
Keywords: ADHD, anxiety, concurrent, adolescent, delinquency, aggression, commitment of violent acts
Concurrent anxiety symptoms in attention-deficit/hyperactivity disorder symptoms related to adolescent delinquency, aggression and commitment of violent acts
People with problematic and norm breaking behavior have by others, through the years, been sorted into different categories. We all remember ”those” kids in school that were considered disturbing and that seemed to be all over the place except where they should. These kids were often perceived as hyperactive, restless, energetic, easily distracted and impatient. Since that time, the debate and research on attention-deficit/hyperactivity disorder (ADHD) have received extensive focus. Despite all research, we do not know much about potential subgroups of ADHD. Hence, in today’s society, the general picture about ADHD characteristics still remains and the different subgroups are not given considerable attention.
DSM-5 (Fifth Edition of American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, 2013) includes ADHD as a neurodevelopmental disorder.
Neurodevelopmental disorders are characterized by deficits that start in the developmental period, often in early years, and that cause impairment in the individual’s personal, social, academic and/or occupational functioning (American Psychiatric Association, 2013). Specifically, attention-deficit/hyperactivity disorder is defined by impaired levels of inattention, hyperactivity and impulsivity. Firstly, inattention is expressed through an
individual being easily distracted, having difficulty sustaining focus, lacking persistence and being disorganized. Second, hyperactivity expresses itself as enhanced motor activities, excessive fidgeting, tapping, or talkativeness. These are individuals who are not able to sit still, have problems with making noise by tapping their fingers or drumming on the table and often do not stop even when spoken to or starts the same behavior only seconds or minutes after. These individuals can also be excessively talkative, meaning that they talk too much and seem to ignore or do not appear to hear when another person tell them not to. Finally,
behaviors can include not thinking before acting or talking, interrupting or engaging in conversations they are not attended to, or having problems waiting for their turn. Further, the symptoms are inconsistent and/or excessive in relation to the individual’s age and
developmental level (American Psychiatric Association, 2013; Thernlund, 2013). The developmental course of ADHD from childhood into early adolescence shows a pattern of stability and consistency (Barkley, 2006; Thernlund, 2013). According to Almer and Sneum (2012), the prevalence of ADHD in Swedish school children is 2-5 %. Also, research suggests that up to 80% of children clinically diagnosed with ADHD have a persistent diagnosis that follows them into adolescence (Barkley, 2006). Lahey, Pelham, Loney, Lee and Willcutt (2005) suggest that although the ADHD diagnosis is persistent, youth move around between different subtypes of ADHD over time. The three subtypes identified in the DSM-5 are ADHD-combined inattentive-hyperactive-impulsive, ADHD inattentive and ADHD
hyperactive-impulsive (American Psychiatric Association, 2013).In adolescence, evidence further suggests that symptoms of motor hyperactivity are less overt, while symptoms such as restlessness, inattention, impulsivity and poor planning persists (American Psychiatric
Association, 2013, Barkley, 2008). Hence, past research agree on the stability and consistency of the developmental course of ADHD.
It has been theorized that adolescents with ADHD are more prone to develop
antisocial behavior. ADHD symptoms are related to externalizing behaviors, such as conduct problems, disruptiveness, hyperactivity and aggressiveness (Hinshaw, 1987). Specifically, adolescents with such externalizing behaviors have been shown to engage in more norm breaking and antisocial behavior than others their age (American Psychiatric Association, 2013; Barkley, 2006; Biederman, et al., 2006; Biederman, Newcorn & Sprich, 1991;
Farrington, 1997; Kuja-Halkola, Lichtenstein, D’Onofrio, & Larsson, 2015; Lee & Hinshaw, 2004; Liu, 2004, Molina et al., 2007; Sibley et al., 2011) In a study by Mannuzza, Klein and
Moulton III (2008) it was found that childhood ADHD, with and without comorbid conduct disorder, increased the chance of developing adolescent antisocial behavior. Therefore, the development of antisocial behavior in adolescents with ADHD does not solely depend on comorbid conduct disorder in childhood. Overall, Moffitt and Scott (2008) have identified familial transmissions of ADHD and other parental psychopathology, such as learning difficulties and school problems, interaction problems, neurocognitive impairments and increased psychiatric comorbidity as risk factors for antisocial behavior in adolescence among children with ADHD.
ADHD is also a risk factor for poor academic performance and rejection by peers. For example, children with attention-deficit/hyperactivity disorder tend to have lower academic and school performance than children without ADHD (Barkley, 2006; Fischer, Barkley, Edelbrock & Smallish, 1990), which in turn have been found to be associated with early onset of antisocial behavior (Einat & Einat, 2008). Moreover, a clinical study found that children with ADHD expressed more aggressive behaviors, were more frequently rejected by peers, had impaired social skills and tended to think highly of themselves in social and behavioral terms, which were found to predict aggressiveness and antisocial behavior in adolescence (Murray-Close et al., 2010). Further, substance abuse has also been found to be associated with ADHD (Molina et al., 2007). Lastly, Öhlmèr (1998) suggests that adolescents with ADHD suffer from alienation because they are perceived by others as disruptive. As a reaction to this, the adolescent feel lonely and abandoned and seek company by others who share the same experiences. This may result in that the adolescent seek out norm breaking and delinquent behaviors. In conclusion, there are several possible factors that play a role in the development of antisocial behavior in adolescents with ADHD.
Engagement in antisocial behavior among adolescents with ADHD is, as noted, relatively common. Some adolescents may engage in more normative antisocial behaviors
such as having stolen a bicycle, shoplifting or smoking, whilst others engage in more serious offenses such as having stolen a car, assault or vandalism. A study examining factors in childhood that may affect antisocial behavior in adulthood found four different trajectory groups (Odgers et al., 2008). The prevalence of ADHD was found to be highest in the
subgroup labeled childhood-onset/life-course-persistent (38%), followed by childhood-limited (12%), adolescent-onset (6%) and the low-trajectory group (3%). These findings suggest that the prevalence of ADHD is associated with a severe and stable pattern of antisocial and delinquent behavior.
Anxiety has been recognized to be comorbid with attention-deficit/hyperactivity disorder. A clinical study showed that around 25% of children with ADHD have a comorbid anxiety disorder (Jensen, Martin & Cantwell, 1997). Anxiety disorders are characterized by consistent and impairing levels of anxiety, worry, and/or avoidance (American Psychiatric Association, 2013). There are several possible explanations for the comorbidity between ADHD and anxiety; some of them concern heritability, temperament, and family influences (Jarrett & Ollendick, 2008). Research suggests that adolescents with ADHD who also experience anxiety are in the risk zone of a number of negative outcomes. For example, children with comorbid ADHD and anxiety perform poor on tasks involving attention compared to children with ADHD only (Brown, 2000; Pliszka, Carlson & Swanson, 1999). These children have longer reaction time, do not appear to display hyperactivity and seem inattentive. A clinical study suggests that these children have problems planning for the future, attain goal-directed tasks, are less determined and seem to have problems with their working memory including being forgetful and have a hard time holding information for processing (Barkley, 1997). According to Schatz and Rostain (2006), the combination of ADHD and anxiety is typically detected later in life rather than earlier in life like ADHD symptoms alone do. The proposed explanation is that symptoms such as impulsivity is easier
to detect than anxiety since it is mainly expressed through internalizing emotions. Further, ADHD with comorbid anxiety symptoms have been reported to be associated with lower social skills (Becker, Langberg, Evans, Girio-Herrera & Vaughn, 2014), higher psychosocial impairment (Cuffe et al., 2015) and suicidal attempt (Balazs, Miklosi, Kereszteny, Dallos & Gadoros, 2014). These findings suggest that children and adolescents with concurrent symptoms of ADHD and anxiety are an unique group that is associated with differential negative outcomes than ADHD-only children and adolescents.
Gender and ADHD subtypes (e.g., ADHD-combined, ADHD-hyperactive/impulsive and ADHD-inattentive) have been found to be associated with different outcomes. Beckman (2004) implicates that there is a two to three times higher prevalence among boys than girls to receive a clinical diagnosis of ADHD. Thus, the criteria for the disorder are very bound to the “boyish” norm, which complicates diagnostic criteria for girls. Socialstyrelsen (2010) states that symptoms of hyperactivity is found more rarely in girls than in boys, and that girls tend to be more introvert and have lower self-esteem than boys. Girls with ADHD are therefore proposed to show patterns of lower activity in regards to hyperactivity in childhood. Another difference is that girls show a higher rate of somatization (e.g. symptoms such as fatigue, stomach ache and panic attacks), which is also the main reason for seeking help. Boys on the other hand show higher rates of developing delinquent behaviors and substance abuse
(Socialstyrelsen, 2010). In terms of the propensity of developing ADHD, research suggests that boys are more likely to develop comorbid ADHD with anxiety (Bauermeister et al., 2007). They also found that boys are more likely to develop the more severe type of ADHD in which is called combined type, that is, expressed through hyperactive, impulsive and
inattentive characteristics. The combined type is in other words the fully developed type of ADHD with both attention and hyperactivity problems. Further, girls are more likely to develop anxiety in the predominantly inattentive subtype which explains why some youths
struggle with attention more than hyperactivity (Bauermeister et al., 2007). Research also suggests that girls with this subtype have a greater likelihood for having comorbid anxiety disorder than boys with the same inattentive type of ADHD. This suggests that gender is not the only factor that predicts behavioral issues in ADHD and that the subtypes of the disorder, is of high value in research and intervention in psychosocial well-being in adolescents with ADHD (Bauermeister et al., 2007; Bremberg & Dalman, 2015; Gross-Tsur et al., 2006; Levy, Hay, Bennett & McStephen, 2005; Norén et al., 2016; Rucklidge, 2010).
The relationship between antisocial behavior in adolescents with concurrent ADHD and anxiety show inconsistent results. Research shows that ADHD is independently
associated with anxiety and conduct problems. How adolescents with ADHD and comorbid anxiety display different forms of conduct problems however, are rather unexplored and the narrow research in the field shows varied results. On the one hand, Kerr, Tremblay, Pagani and Vitaro (1997) suggest that anxiety in the presence of ADHD in boys may lead to
inhibition, which was found to be a protective factor against developing delinquent behavior. Bilgiç et al., (2013) suggests that anxiety symptoms are a possible consequence of present conduct disorder in ADHD youths, not the other way around. Further, adolescents with comorbid ADHD and anxiety have been found to not display aggressive behaviors (Becker, Luebbe, Stoppelbein, Greening & Fite, 2012; Connor, Chartier, Preen & Kaplan, 2010). On the other hand, findings also suggest that ADHD with comorbid anxiety are consistently associated with higher prevalence rates of conduct problems (Humphreys, Aguirre & Lee, 2012). It has also been found that children with comorbid ADHD and anxiety have a harder time controlling their emotions and behaviors (Sorensen, Plessen, Nicholas & Lundervold, 2011). Kerr, Tremblay, Pagani & Vitaro (1997) found that concurrent anxiety and ADHD in boys may lead to social withdrawal which was found to be a risk factor in the development of delinquent behavior. Also, in a study by Falk, Lee and Chorpita (2015) it was found that
adolescents with comorbid ADHD and anxiety were less aggressive but equally engaged in delinquent behaviors in comparison to adolescents with ADHD only. The findings in the study also revealed that anxious adolescents reported less delinquent behaviors in comparison to adolescents with ADHD only and comorbid ADHD and anxiety. Thus, the authors
addresses that one limitation with the study is that the sample consisted of a wide range of participants with ages varying from 5-17 years. The results showed that age were significantly associated with conduct problems, and the authors then suggest future research to look more in detail at different developmental stages. In terms of treatment, a study reviewing existing studies on the influence of comorbid ADHD on treatment of youth with anxiety symptoms found that youth with ADHD or symptoms of ADHD had worse treatment outcomes in comparison to those without comorbid ADHD (Halldorsdottir & Ollendick, 2014). In conclusion of this result, we can assume that adolescents with comorbid ADHD and anxiety and anxious adolescents without ADHD are in need of different treatment-approaches. How adolescents with concurrent symptoms of ADHD and anxiety respond to treatment aimed at reducing antisocial behavior has not been explored. Therefore, gaining a deeper
understanding of the subgroup with concurrent ADHD and anxiety is needed.
The purpose of this study is to identify if it exists subgroups of adolescents with different levels of ADHD-symptoms and anxiety, and examine whether these subgroups differ from each other in expected ways. Our research question therefore is if there are subgroups of adolescents with high and low levels of ADHD and anxiety. We hypothesize that there will be a unique subgroup that show high levels of both ADHD and anxiety symptoms. In line with the results from Falk, Lee and Chorpita (2015) study, we hypothesize that the subgroup with high levels of ADHD and anxiety symptoms will report equal levels of delinquency and lower levels of aggression in comparison to the adolescents with ADHD only. Further, we
it is a behavior related to aggression. Considering gender differences, earlier research suggests that boys score higher in delinquency and aggressive behavior than girls. Further, research suggest that ADHD is a risk factor for developing delinquent behavior, in contrast to anxiety which is suggested to be a protective factor (Polier, Vloet & Herpertz-Dahlmann, 2012; Kerr, Tremblay, Pagani & Vitaro, 1997). We therefore hypothesize that boys will show higher levels of ADHD and anxiety symptoms compared to girls. Lastly, since research suggests that the different subtypes of ADHD predict different behavioral problems (Bremberg & Dalman, 2015) we further want to explore differences in external variables and how these are
associated with attention and hyperactivity/impulsivity problems. Since past research suggest that symptoms of hyperactivity is found more frequently in boys than in girls, and that boys are more prone to develop delinquent behavior and substance use (Socialstyrelsen, 2010), we hypothesize that symptoms of hyperactivity/impulsivity are going to be more strongly
associated to the external variables compared to symptoms of inattention. Method
Participants
The obtained sample consisted of 1072 adolescent boys (52.6 %) and girls (47.4 %) and their parents from a cross-sectional community-based study in a Swedish city. The sample consisted of 360 students from grade 7 (33.6 %), 354 students from grade 8 (33 %) and 358 students from grade 9 (33.4 %), with a mean age of 14.28 and standards deviation of .94. Ninety point five percent of the students had a Swedish origin and 8.7 % had a non-Swedish origin in the current sample.
Procedure
The present study is conducted through secondary data from a cross-sectional study described in Salihovic, Kerr and Stattin (2014). Participants were informed by a research assistant about the purpose of the study and that the participation was entirely voluntary.
Afterwards, questionnaires were given out, and teachers and administrators left the room while the adolescents filled out the questionnaires. Questionnaires and a postage-paid return envelope were also sent to each parent of the adolescents. To decline the adolescents’ participation, the postage-paid return was to be sent back to the researcher. The study, measures and procedures were approved by Örebro University’s Ethics Review Board. Measures
Attention Deficit/Hyperactivity Disorder Symptoms (ADHD). The measure for ADHD was based on the criterion of DSM-IV. More specifically, a parent-reported scale of ADHD symptoms created by Swanson, Nolan and Pelham (2001) was used (e.g., SNAP-IV). The measure contained two separate subscales: hyperactivity, impulsivity and attention
problems. Range of response ranged from 1 (Does not apply at all) to 4 (Applies exactly). The first subscale Hyperactivity/impulsivity was measured with eight statements such as:
“Difficulties of sitting still,” “Often seems to be on the go” and “Often talks excessively much”. Attention problems were measured through nine statements such as: “Often has difficulties to follow instructions and therefore often fails to complete tasks” and “Often doesn’t seem to listen when directly spoken to”. The inter-item reliability of the
hyperactivity/impulsivity measure was .87 and for the attention problem measure .91. Anxiety. The anxiety measure was used in Salihovic, Kerr and Stattin (2014) previously. The adolescents’ anxious behavior were collected through six parent-reported statements. The range of the statements were 1 (Does not apply at all) to 4 (Applies exactly). The items were “Often worries about things without a reason,” “Often thinks about everything that can go wrong or bad before he/she does things,” “Is often more nervous than others in his/her age,” “Often has problem falling asleep because of his/her thoughts about difficult things,” “Often worries about things that could happen in the future” and “Worries a lot unnecessarily”. The inter- item reliability was .82.
Delinquency. The delinquent behavior measure was developed by Haynie (2001) as cited in Salihovic, Kerr & Stattin (2014). The content of the measures was 22 items of self-report measures and has been validated in earlier studies. The items were conducted in a way that they will intercept delinquent behaviors during the past years, with statements that asks for: “Caught by police for something you have done” and “Have you taking part in stealing something from a car”. Items were rated on a 5-point scale ranging from 1 (No, it has never happened) to 5 (More than 10 times). This scale can be divided into subscales for violence, serious offenses, minor offenses, and substance use. The inter-item reliability for the delinquency scale was .93 and for each subscales separately .80, .87, .91, and .81.
Aggression. The scale measuring aggression was used in by Salihovic, Kerr and Stattin (2014) and was a self-reported measure consisting of 21 statements including both reactive and proactive aggression. The responses ranged from 1 (Does not apply at all) to 4 (Applies exactly). Examples of statements are: “If I am really mad at someone, I scream at him/her” and “I can’t tolerate being provoked – I’ll start fighting”. The inter-item reliability of the measure was .83.
Commitment of violent acts. The scale was developed by Andershed, Stattin and Kerr (2001) to measure threats and violence on the street. The current study we use the name Commitment of violent acts because it is a more understandable conception of the scale. The response format ranged from 1 (No, it has not happened this spring semester) to 4 (Yes, it has happened 4 or more times). Questions included; “Have you taken part in attacking others at night without them having threatened or attacked you or your friends’ first?” and “Have you taken part in kicking anyone who was lying down or kicking someone in the head?” The inter-item reliability was .71.
In our study, a hierarchical cluster analysis with a range from two to ten-class solutions was used to identify subgroups with different combinations of ADHD and anxiety symptoms. When estimated, a nonhierarchical (e.g., k-mean) cluster analysis was used to look more in detail at the identified clusters. Clustering techniques are used to explore data in way to create clusters (e.g., groups) of objects or individuals that resembles each other and that departs in another way from the other clusters (Everitt, Landau, Leese & Stahl, 2011). In this study, adolescents with similar levels of ADHD and anxiety were identified and classified to belong to the same group.
Further, to examine if there were significant mean differences on the dependent variables between the subgroups, we used one-way ANOVA (Analysis of Variance) with Bonferroni’s post hoc comparison. Further, 2x4 Factorial ANOVA was used to examine if there were any significant mean differences of gender on the dependent variables. Statistical Package for the Social Sciences (SPSS) version 23 was used to run the analyses.
Results
To answer our research question whether there is a significant association between attention-deficit/hyperactivity disorder (ADHD) symptoms and anxiety symptoms on delinquency, aggression and commitment of violent acts, we ran two-tailed bivariate
correlations between the clustering variables and dependent variables (see Table 1). Pearson correlation suggested small to moderate associations between ADHD symptoms and overall delinquency, r(673) = .23, p < .001, aggression, r(658) = .19, p < .001, and commitment of violent acts, r(628) = .19, p < .05. Further, anxiety itself was found to only be significantly associated with minor property offenses, r(675) = .08, p < .05. The correlation between ADHD and anxiety was found to be positive r(742) = .49, p < .001.
Table 1.
To answer the question; Are there significant subgroups with similar levels of ADHD and anxiety symptoms? We first ran a hierarchical cluster analysis to see how many
meaningful groups there was within our sample. The results revealed four subgroups with different levels of ADHD and anxiety symptoms. To look into these subgroups more
carefully, we ran a k-mean cluster analysis with Euclidean distance. Eighty students (7.5 %) were classified to belong to a subgroup we labeled as “ADHD-anxiety” which had both high levels of ADHD and anxiety symptoms, which confirm our hypothesis that a unique subgroup with high levels of these symptoms would be identified. Further, a subgroup with low levels of ADHD and anxiety symptoms was found, labeled “non-symptom” (n = 270). Also, one group with high levels of ADHD symptoms and low levels of anxiety was found, labeled “ADHD-only” (n = 193), and one group with anxiety symptoms only labeled “anxiety-only”
Variables M SD 1. 2. 3. 4. 5. 6. 7. 8. 9. 1. ADHD 1.85 .53 - .49** .23*** .16*** .23*** .05 .13*** .19*** .19** 2. Anxiety 1.82 .58 - .02 .08* -.01 -.01 .02 -.01 .06 3. Delinquency 1.16 .34 - .79*** .91*** .43*** .71*** .42*** .60** 4. Severe property offences 1.06 .27 - .57*** .46*** .60*** .23*** .47** 5. Minor property offences 1.33 .57 - .33*** .50*** .45*** .45** 6. Substance use 1.07 .41 - .36*** .21*** .22** 7. Violence 1.05 .24 - .24*** .60** 8. Aggression 1.97 .45 - .23** 9. Commitment of violent acts 1.08 .33 - Note. * < .05; ** p < .01; *** p < .001. (N = 1072).
(n = 199). Overall, four subgroups of interest were identified based on levels of ADHD and anxiety symptoms.
To examine whether these subgroups are meaningful, we compared them on several external variables. We predicted that adolescents with ADHD and anxiety would score
equally on overall delinquency and score lower on aggression and commitment of violent acts compared to adolescents with ADHD only. The results from the one-way ANOVA showed that there was a significant difference in the involvement in delinquent behaviors, F (3,670) 5.56, p < .001, levels of aggression, F (3,655) = 6.79, p < .001, and commitment of violent acts, F(3, 625) = 3.20, p < .05, across the four subgroups. Specifically, adolescents with high levels of ADHD symptoms reported higher levels of delinquency (M = 1.24, SD = .38) than did the ADHD-anxiety subgroup (M = 1.21, SD = .57), the non-symptom subgroup (M = 1.12, SD = .29) and the anxiety-only subgroup (M = 1.11, SD = .27). Also, the ADHD-only subgroup showed higher levels of aggression (M = 2.08, SD = .49) than did the ADHD-anxiety subgroup (M = 2.04, SD = .53), non-symptom subgroup (M = 1.92, SD = .43 and anxiety-only subgroup (M = 1.89, SD = .38). Further, the ADHD-anxiety subgroup scored highest on the subscale commitment of violent acts (M =1.18, SD = .56), followed by ADHD-only (M = 1.09, SD = .32), non-symptom (M = 1.06, SD = .26) and anxiety-ADHD-only (M = 1.04, SD = .21). On the one hand, our hypothesis that the ADHD-anxiety subgroup would report lower levels of aggression in comparison to the ADHD-only subgroup was supported. On the other hand, our hypotheses were not supported regarding involvement in delinquent behavior and commitment of violent acts.
Further, when examining the specific forms of delinquent behaviors, we found significant differences across the four subgroups regarding severe property offenses, F(3, 672) = 3.42, p < .05, and minor property offenses, F(3, 672) = 7.20, p < .001. Specifically, adolescents with concurrent ADHD-anxiety symptoms showed higher scores of minor
property offenses (M = 1.38, SD = .53) than did those with ADHD-only (M = 1.09, SD = .29), anxiety-only (M = 1.03, SD = .23) and non-symptoms (M = 1.03, SD = .18) Thus, no
significant differences were found regarding the subscales violence and substance use across the four subgroups.
To examine if there were any gender differences across the four subgroups on delinquency, we ran a 2x4 factorial ANOVA. The results showed that there were significant main effects of subgroups, F(3, 666) = 3.95, p < .05, and gender, F(1, 666) = 20.62, p < .001, on delinquency. On the other hand, there was no significant interaction effect of subgroups and gender on delinquency, F(3, 666) = .09, p = 96. Specifically, boys reported slightly higher
Table 2.
Standardized mean level between the subgroups ADHD-Anxiety (n=80) Non-Symptom (n=270) ADHD-only (n=193) Anxiety (n=199) F M M M M Variables Delinquency 1.21 1.13 1.24 1.12 5.56***
Severe property offences 1.13 1.03 1.24 1.12 3.42*
Minor property offences 1.38 1.03 1.09 1.03 7.20***
Substance use 1.06 1.08 1.08 1.04 .66
Violence 1.10 1.05 1.07 1.04 .97
Aggression 2.04 1.92 2.08 1.89 6.79***
Commitment violent acts 1.18 1.06 1.10 1.04 3.20*
ratings of delinquent behaviors (M = 1.24, SD = .02) than did girls (M = 1.10, SD = .02), meaning that our hypothesis was supported.
We also ran a 2x4 factorial ANOVA of gender and subgroups on aggression. The result revealed a significant main effect of subgroups, F(3, 651) = 5.66, p < .001. Thus, the results revealed a nonsignificant main effect of gender, F(1, 651) = 1.32, p = .25 and a nonsignificant interaction effect of subgroups and gender, F (3, 651) = .10, p = .53. Our hypothesis that boys would score higher in aggression was therefore not supported.
Lastly, we performed a 2x4 factorial ANOVA of gender and subgroups on
commitment of violent acts. The results showed that there was a significant main effect of gender, F(1, 621) = 17.89, p < .001, and subgroup, F(3, 621) = 2.75, p < .05. Thus, there was no significant interaction effect of gender and subgroup found on commitment of violent acts, F(3, 621) = 1.00, p < .05. Specifically, boys reported higher levels of committing violence (M = 1.15, SD = .02), than did girls (M = 1.03, SD = .02).
By looking at the correlations between symptoms of inattention and
hyperactivity/impulsivity and the external variables we found that symptoms of inattention had slightly stronger correlations with the external variables than did symptoms of
hyperactivity/impulsivity. More specifically, all external variables was positively associated with symptoms of inattention, and all external variables except substance use was positively associated with hyperactivity/impulsivity (see Table 3). We hypothesize that
hyperactivity/impulsivity would be more strongly related to delinquency, aggression and commitment of violent acts. These findings do not go in line with our expected outcome.
Table 3.
Descriptive statistics and bivariate correlations
Discussion
The present study was conducted to expand the knowledge on adolescents with concurrent ADHD and anxiety symptoms. More specifically, we used a normative sample of adolescents to examine if there exists subgroup with different levels of ADHD and anxiety symptoms and if these subgroups differed in their involvement in delinquency, aggression and commitment of violent acts. Four subgroups were identified, and as we expected, the results revealed a unique subgroup with high levels of both ADHD and anxiety symptoms.
Furthermore, the findings revealed that the subgroups differed regarding their involvement in acts such as theft, vandalism, shoplifting, being caught by the police and burglary. They also differed in their levels of aggressive behaviors and commitment of violent acts (e.g. attacking, kicking or threatening someone). The results suggested no differences across the subgroups
Impulsive (n=740) (n=742) Variables M SD Delinquency 1.16 .34 .18*** .23*** Severe property offences 1.06 .27 .14*** .15*** Minor property offences 1.33 .57 .18*** .24*** Substance use 1.07 .41 .03 .07*** Violence 1.05 .24 .10*** .14*** Aggression 1.97 .45 .17*** .19*** Commitment of violent acts 1.08 .33 .14*** .21*** Note. *** p <.001
on substance use and violent delinquency (e.g. threatened or forced someone to give you something or carried a weapon). Overall, the results suggest that the adolescents differ from each other in small but meaningful ways.
The main reason for conducting this study was to explore whether adolescents with concurrent ADHD and anxiety symptoms differed from adolescents with only ADHD
symptoms in their involvement in delinquent behavior, aggression and commitment of violent acts. Surprisingly, the adolescents with high levels of both ADHD and anxiety symptoms were revealed to be less involved in total delinquency (e.g. minor property offenses, severe property offenses, violence and substance use) and less aggressive than adolescents with ADHD. This finding was surprising since past research has suggested that adolescents with comorbid ADHD and anxiety are equally engaged in delinquent behaviors as adolescents with only ADHD (Falk, Lee & Chorpita, 2015). Thus, the adolescents with concurrent ADHD and anxiety symptoms reported being more involved in minor property offenses including
behaviors such as shoplifting and stolen a bike, and commitment of violent acts such as having threaten someone or carried a weapon. These measures (e.g. minor property offenses and commitment violent acts) reflect two different forms of delinquent behaviors which mean that adolescents with concurrent ADHD and anxiety symptoms show higher prevalence of some delinquent behaviors. However, our hypothesis that the anxiety and ADHD-only subgroups would be equally engaged in delinquent behaviors is not supported by our findings.
Past research agree on the comorbidity between ADHD and anxiety (Jarrett & Ollendick, 2008; Jensen, Martin & Cantwell, 1997). However, the association to antisocial behavior and aggression are rather unexplored and the existing research lack consistency (Becker et al., 2012; Bilgiç et al., 2013; Connor et al., 2010; Falk, Lee & Chorpita, 2015; Humphreys, Aguirre & Lee, 2012; Kerr, Tremblay, Pagani & Vitaro, 1997). Firstly, past
research suggest that anxiety may be a protective factor against delinquent behavior, which suggest that the more anxiety in an adolescent, the less involved in delinquent behavior (Kerr, Tremblay, Pagani & Vitaro, 1997). The findings in our study suggest that adolescents with ADHD, and adolescent with concurrent ADHD and anxiety, both report higher levels of delinquency, minor property offences, aggression and commitment of violent acts, in
comparison to the other subgroups. These findings suggest that anxiety when accompanied by ADHD-symptoms in an adolescent is not a protective factor. In conclusion, the results in the present study show that the ADHD-anxiety, ADHD-only and anxiety-only subgroups differ in meaningful way and that these subgroups should be treated different in health care and
interventions. Further, earlier studies suggest that the prevalence of ADHD is two to three times more common among boys than girls (Beckman, 2004). It is also suggested that anxiety is more common among adolescent boys than girls in the combined type of ADHD
(Bauermeister et al., 2007). Also, since past research suggest that adolescents with concurrent ADHD and anxiety are equally engaged in delinquent behaviors and less aggressive than adolescents with ADHD only (Falk, Lee & Chorpita, 2015), we hypothesized that boys would be more delinquent and aggressive than girls. These speculations are partly supported since boys showed higher levels of delinquent behavior in the present study. On the other hand, there were no differences found between boys and girls on aggression, which is an interesting finding that future research examining this subgroup should look into. Falk, Lee and Chorpita (2015) suggest that the subgroups that reported the highest prevalence of delinquent behavior are adolescents with ADHD only and comorbid ADHD and anxiety. By ranking the
subgroups from the lowest to highest regarding reported involvement in delinquent behavior, the following is: ADHD-only and ADHD-anxiety, non-symptom and anxiety-only. These findings are partly supported by the findings in our study and since past research have used clinical measures; our findings are valuable in the aspect that we have used measures that
capture symptoms that is not necessarily clinical. The uniqueness in our findings are that our study support previous research on clinical measures which shows that there are adolescents with non-clinical symptoms that show similar problematic behaviors comparable to clinically diagnosed adolescents. Regarding aggression however, past research have found that
aggression is not associated to adolescents with concurrent ADHD and anxiety (Becker et al., 2012; Connor et al., 2012), which do not go in line with the results from our study. Other studies (Falk, Lee & Chorpita, 2015) suggest that youth with concurrent ADHD and anxiety are less aggressive than youth with ADHD only and youth without any symptoms, in which partly support our findings. More specifically, the ADHD-anxiety subgroup in the present study showed lower levels of aggression than ADHD-only subgroup, but higher levels of aggression than anxiety-only and non-symptom subgroups. Hence, our findings provide new information about this unique subgroup that previous research has not concluded.
Possible theoretical explanations to why adolescents with ADHD only and concurrent ADHD and anxiety report higher ratings of total delinquency, aggression and commitment of violent acts than adolescents with only anxiety symptoms and adolescents without any
symptoms of ADHD and anxiety, is that the adolescent with ADHD or concurrent ADHD and anxiety symptoms may feel as an outcast and alienated or stigmatized by others. Öhlmèr (1998) suggests that peers may reject adolescents with ADHD because they are perceived as disruptive or as a “threat”. The rejection may lead the adolescent feeling alienated and he/she may therefore seek company in equally minded youth. The gathering of these adolescents sharing a feeling of not belonging and not being good at something, may in turn lead them to engage in norm breaking and delinquent behaviors. Similarly, Lebowitz (2016) suggests that adolescents with ADHD tend to be more alienated because of stigmatization. Others can view the behaviors or symptoms of ADHD as annoying (e.g., bad character and poor discipline). These types of behaviors do not go in line with how the conventional society works and this
lead to problems for adolescents with ADHD. Adolescents that are getting stigmatized tend to distance themselves from others because of the shame in being diagnosed with a disorder. These types of stigmatization and alienation are causing severe stress to the adolescent that shows symptoms of ADHD and this may lead to the development of anxiety. This may explain why adolescents with ADHD only and concurrent ADHD and anxiety symptoms are similar to each other in different variables in our study.
Unexpected findings in the current study are that adolescents with concurrent ADHD and anxiety reported higher levels of violence and commitment of violent acts than
adolescents with ADHD symptoms only. Although speculating that adolescents with concurrent ADHD and anxiety would be equally involved in delinquent behaviors, we expected them to be less aggressive. In contrary, they reported being less aggressive than adolescents with ADHD only. Thus, the results suggest that adolescents with concurrent symptoms of ADHD and anxiety show more aggressive forms of delinquent behaviors (e.g. violent crimes and commitment of violent acts). Also, by looking at the correlations of symptoms of attention and hyperactivity/impulsivity problems on the external variables we found that inattention was more strongly related to total delinquency, aggression and
commitment of violent acts. These findings do not go in line with what we expected and may also be considered in future research for the development of interventions and treatment regarding adolescents with ADHD with antisocial behavior.
Limitations with the present study is the cross sectional design which means that no implications about causation and future prediction can be made. Further, since the data are collected in a community-based sample with self- and parent-reported measures, we can only talk about symptoms of ADHD and anxiety. The results can therefore not be generalized and used in clinical settings. Thus, since we have used a normative sample, the results are
limitation with the design, also mentioned in Salihovic, Kerr & Stattin (2014), is that the youth were asked to fill in the questionnaire during school hours on a regular day. The youths mostly engaged in antisocial behavior may not have been present during the day of the data collection because of truancy, and valuable participants may therefore have been failed to assess. Lastly, since the anxiety measure is a parent-reported measure and feelings of anxiety are internalized feelings, the results may not reflect the adolescents’ feelings of anxiety fairly. Thus, in future research, validation with self-report measures are needed.
Strengths with this study are that it was conducted in a normative community-based sample. The sample further consisted of 1072 adolescents and their parents, including both boys and girls in ages 12-17. The gist of this sample is that it is a representative sample of adolescents. The conclusions made in this study may therefore be applied and generalized to normal populations of adolescents and in Swedish context. Another strength with this study is that previous research on adolescents with concurrent ADHD and anxiety are rather
unexplored, meaning that our study adds valuable information about the subgroup which can be used in future research, and in intervention and treatment. Further, no study examining this unique subgroup on outcomes like aggression and antisocial behavior has been done in a Swedish context before. Therefore, strengths with the present study is that our findings support that this group do exist.
Future research examining alternative interventions and treatment for adolescents with comorbid ADHD and anxiety is needed. That comorbid group of youth may worsen the treatment outcome (Halldorsdottir & Ollendick, 2014). Psychotherapy has been found to be a successful treatment for adolescents with ADHD since the ability to self-reflect develops during adolescence (Thernlund, 2013). On the other hand, other research suggests that the core symptoms (e.g. inattention and/or hyperactivity/impulsivity) related to ADHD may interfere with cognitive-behavioral treatment (CBT) since most CBT require the child to pay
attention and to stay involved and engaged (Pelham & Fabiano, 2008). Hence, past research do not agree on the effectiveness of CBT on youth with ADHD. Further, treating youth with comorbid symptoms of ADHD and anxiety have been suggested to depend greatly on habituation. The habituation is suggested to require uninterrupted contact with the identified “anxiety-source” to successfully reduce anxiety symptoms. Again, the core symptoms of ADHD are suggested to interfere with the habituation, which in turn make the CBT
ineffective (Davis & Ollendick, 2005). Based on these findings we can assume that anxious adolescents with and without comorbid ADHD may be in need of different
treatment-approaches. Regarding delinquency, aggression and commitment of violent acts however, no study to this date have examined treatment outcomes for adolescents with concurrent
symptoms of ADHD and anxiety. Since the current study suggests that these adolescents differ in their involvement and levels of delinquent behaviors, aggression and commitment of violent acts, future research should focus on treatment for this subgroup. Also, research conducted using a longitudinal study design would be essential in the development of
prevention and treatment since it gives information about direction and causation on external variables.
At the expansive level, our results revealed a unique subgroup with high levels of ADHD and anxiety symptoms. This means that some adolescents with attention, hyperactivity and impulsivity deficits are also accompanied with feelings of anxiety. These findings suggest that ADHD is not a homogenous disorder, and that unique subgroups of the disorder exist. In the current study, we revealed that adolescents with concurrent symptoms of both ADHD and anxiety differed from the adolescents with only ADHD in small, but meaningful ways. Hence, concurrent symptoms in adolescents with ADHD should be considered in intervention and treatment that is based on individual differences in the disorder.
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