Those living with a diagnosis of attention-deficit hyperactivity disorder (ADHD) face, every day of their lives, significant obstacles in achieving their most important personal goals.

And not only because of the impact of alterations in executive functions, such as attention and/or behavioural inhibition, but also because of the “social frictions” in which their particular clinical expression is involved. From a very young age they can be considered agitated or even violent, which conditions the way they live this period of time.

The literature on ADHD suggests that, beyond the limitations that this neurodevelopmental disorder imposes, the emotional consequences related to difficulties in achieving school goals or meeting all the demands of a job also contribute.

In this article we will address some of the comorbidities of ADHD . All of them are important, since they are linked to a worsening of the symptomatology and/or its prognosis and evolution. Without further ado, let us move on to this important issue.

Attention Deficit Hyperactivity Disorder

ADHD is a neurodevelopmental disorder that is associated with three different symptoms , namely: impulsivity (problems inhibiting impulses or delaying incentives), inattention (difficulty in maintaining “focus” for the necessary time on a task being performed) and motor hyperactivity (feeling of urgency and inability to remain in a state of stillness in contexts where it should be done). There are different profiles of ADHD, since each person who suffers from it refers to very different symptoms (emphasis on inattention or hyperactivity, or even a mixture of both).

It is estimated that between 3% and 10% of the child population presents symptoms compatible with this diagnosis according to the DSM-5 manual, with an expression that very often begins before the age of five and exceptionally debuts after the age of seven. The resonances on cognition, especially in executive function (planning or inhibitory control), imply notorious consequences on several areas of daily functioning. Therefore, many of those have been used to explain the comorbidities that the literature has detected for this same group of patients.

Comorbidity is understood as the presence of two or more clinical entities (including ADHD) simultaneously in a single individual (child or adult), in such a way that a synergic relationship is drawn between them. The result cannot be calculated through a simple sum of the diagnoses, but rather an interaction between them is produced from which a unique manifestation is derived for each of the people who might present it. And this is because these comorbid disorders are mixed with personality and character dimensions, resulting in a deep psychopathological idiosyncrasy.

In patients with ADHD, comorbidity is the rule, not the exception, and therefore the presence of all disorders must be taken into account, which will be detailed from the very beginning of the therapeutic relationship (initial interview with parents and infant, definition of assessment strategies, etc.). It is also known that comorbidity can overshadow the prognosis and accentuate the obstacles that the family will have to deal with as time goes by, given that up to 50% of cases extend beyond adolescence.

Comorbidities of Attention Deficit Hyperactivity Disorder

We proceed to detail the six disorders that most frequently occur along with ADHD. Although at first there was a very special emphasis on externalizing disorders (disruptive behaviors), now we are beginning to consider the importance of internalizing disorders (major depression, for example) for the balanced development of the person with this clinical picture.

1. Major depression

Depression is a disorder characterized by deep sadness and great difficulty in experiencing pleasure . In the case of children, as well as adolescents, it is sometimes expressed as irritability (and is confused with behavioural disorders). The scientific community is increasingly aware of the possibility that such a mood problem may occur in those who have been diagnosed with ADHD, very often as an emotional result of existing limitations in adapting to school or in forging relationships with their peers.

In any case, it is estimated that between 6% and 9% of children and adolescents with ADHD have a comorbid diagnosis of depression , which increases their subjective level of stress and exacerbates the basic cognitive problems. These are conditions that debut much earlier than what is observed in the general population, and which require the design of more intense and longer-term interventions. The high concurrence of both of them meant the definitive incentive for the research community to set out to define the common aspects that could explain and predict it.

After multiple studies on this subject, it was concluded that the common axis was emotional dysregulation; understood as the presence of excessive affective reactions in contrast to the triggering event, the great lability of internal states and the excessive emphasis on past negative experiences or ominous expectations for the future. Among all the characteristics associated with such a relevant shared factor, intolerance to frustration rises as the one with the greatest explanatory and predictive power .

It has been described that up to 72% of children with ADHD present this trait, which is expressed as a relevant difficulty to delay the reward or tolerate the existence of obstacles that prevent its immediate and unconditional achievement. This circumstance would precipitate the emergence of a recurrent feeling of failure, the dissolution of any motivation for the achievement of goals and the solid belief that one is different and/or inappropriate. All this can be accentuated when, in addition, one lives every day with constant criticism.

2. Anxiety disorders

Anxiety disorders are also very common in ADHD. Studies on this issue conclude that between 28% and 33% of people with this diagnosis meet the criteria for an anxiety problem , and especially when they reach adolescence. It is also at this point that differences between boys and girls begin to be noticed in terms of the risk of suffering them, being much more common in them than in boys. When comparing subjects with and without ADHD, it is noted that in the first case these disorders emerge at younger ages and are more durable.

Children with ADHD show higher levels of social anxiety than those without it , and are more likely to refer to acute panic attacks and specific phobias. The latter may be formed by evolutionarily normal fears that persist despite the passage of time, which accentuates them and accumulates them with those that arise during later periods. There are also studies describing a higher prevalence of generalized anxiety disorder in this population, characterized by constant/inevitable concerns about a large constellation of everyday issues.

It is known that this comorbidity is more common in those with mixed ADHD , that is, with symptoms of hyperactivity/inattention. However, it is believed that attention deficits are related to anxiety in a more intimate way than any other of its forms of expression. In spite of this, anxiety accentuates impulsivity and alterations in executive function to the same extent, aggravating any difficulty (academic, work, etc.) that one may be experiencing.

3. Bipolar disorder

Childhood bipolar disorder and ADHD overlap significantly at the clinical level, so much so that they are often confused and mixed up indistinguishably. Thus, both have a low tolerance to frustration, high irritability and even outbursts that do not fit with the objective characteristics of the fact that triggers them. It is also possible that in both there is difficulty in delaying rewards and “fluctuations” (more or less pronounced) in mood. Because treatment is different in each case, the particular disorder being suffered or whether there is a basic comorbidity must be identified.

There are some differences between bipolar disorder and ADHD that should be considered at the time of evaluation. To distinguish one from the other, it is key to consider the following: in bipolar disorder there is an extensive family history of this same clinical picture, there are periods of great expansiveness of mood, irritable versus depressive affectivity stands out, emotional shifts are more frequent/severe, and a tendency to grandiosity in the way one thinks about oneself is evident.

Finally, it has also been described that about half of the infants with bipolarity present inappropriate sexual behaviors, or what is the same, that do not correspond to their age and that are deployed in contexts where they are disruptive (masturbation in public places, for example). All this without a history of abuse (context in which these habits can arise in a common way).

In addition, they also express with some frequency that they do not need to sleep , something that must be distinguished from the reluctance to go to bed with ADHD.

4. Addictions

Addictions are also a very important problem in ADHD, especially when you reach adolescence , where the danger of substance abuse increases fivefold. Research carried out on this essential issue shows figures of between 10 and 24% of comorbid dependence, reaching maximum prevalences of 52% in some of the studies. Although it is believed that there is a sort of preference for stimulant drugs, what is really true is that no clear pattern can be distinguished, with all types of consumption being described (most often an addiction to several substances at once).

A very relevant percentage of adolescents who show evidence of ADHD/addiction showed problematic behavior prior to this stage, which may include discreet theft or other activities that violate the rights of others. There is also evidence of an early debut in recreational-type consumption (often before age 15) along with a substantially higher presence of antisocial personality traits (50% in adolescents with ADHD and addiction and 25% in those with ADHD alone).

It is known that the presence of ADHD symptoms has a negative impact on the prognosis of addiction , and that on the other hand the use of substances alters the effectiveness of the drugs that are usually administered in order to regulate their symptoms (especially central nervous system stimulants). It should not be forgotten, moreover, that the therapeutic approach with such drugs requires the closest possible follow-up in cases of addiction, to avoid inappropriate use.

Finally, work with the family is always essential , aimed at promoting tools that minimize the risk of relapse and preserve relational balance. All drug use is a difficult situation at the level of the social group, and requires adjusting the different roles that have been played up to now. On the other hand, at a systemic level there is what seems to be an indissoluble functional and bidirectional connection: ADHD is more common in families where there is addiction and addiction is more common in families where there is ADHD.

5. Conduct disorders

Conduct disorders are common in children with ADHD. These are acts that are harmful to other people or to the child himself, and are related to a high level of conflict in the family and school environment. Some examples of this can be bullying, discussions with parents that include scenes of physical/verbal violence, petty theft and tantrums whose purpose is to extract a secondary benefit. All of these would definitely result in aggressive, defiant and impulsive behaviour.

When ADHD has these difficulties, it is understood as a specific variant in which the levels of family stress reach a higher threshold than in conventional ADHD. In general the symptoms of inattention, impulsivity and hyperactivity are much more intense ; and they end up torpedoing the child$0027s efforts to overcome the historical milestones associated with each stage of development (which isolates him/her from groups of peers with prosocial tendencies and segregates him/her into marginal groups where dissocial behaviours acquire a normative value and reinforcing power).

The family history of such a comorbidity case is characterized by poor parenting, low supervision of the infant$0027s habits outside the home and even abuse of all kinds and harshness . These are, therefore, environments with an exorbitant level of social conflict, and even families at extreme risk of exclusion. It is not uncommon for one or both of these parents to suffer from serious mental pathologies (including antisocial disorder or chemical and non-chemical addictions). This situation also increases the risk that the child will engage in drug use, aggravating all of his or her problems, as seen in a previous section.

6. Suicide

Suicide is not a disorder in itself, but a dramatic and painful consequence, often involving a long history of psychological pain. In fact, up to 50% of adolescents who try or succeed in suicide suffer from some mental health problem , with an average evolution of two years taking the moment of the suicidal act as a reference. It is known that patients diagnosed with ADHD are more likely to engage in suicidal behavior, to present an autolytic ideation and even to cause themselves injuries of varying degrees.

The literature on this subject is consistent in pointing to adolescence and adulthood as the periods of greatest vulnerability, to the point that 10% of adults with ADHD have tried to take their own lives at least once and that 5% even die from precisely this cause. The risk increases when living with a major depression, a behavioural problem or a substance dependency; and also when the patient is male. This is why, during the treatment of subjects with ADHD and some comorbidity, this possibility must be taken into account.

The cognitive impairments that these patients present, especially in areas such as attention and behavioral inhibition, are associated with an increased risk of suicidal behavior. So much so that many studies on the epidemiology of suicide highlight ADHD as a risk factor for this important health and social problem.

Bibliographic references:

  • Klassen, L., Katzman, M. and Chokka, P. (2009). Adult ADHD and its comorbidities, with a focus on bipolar disorder. Journal of Affective Disorders, 124, 1-8.
  • Sherman, J. and Tarnow, J. (2013). What are common comorbidities in ADHD? Psychiatric Times, 30, 47-59.