Keywords

The medical evaluation of mood disturbance in patients diagnosed with ADHD, like all great quests, begins with a clear definition of what is being pursued. Taber’s cyclopedic medical dictionary defines mood as “a pervasive and sustained emotion that may have a major influence on a person’s perception of the world” [1]. The use of the word “sustained” highlights the importance of considering an emotion’s duration when defining a particular mood state. Duration is partially determined by the individual’s ability to self-regulate emotions, which is a complex learned process. In brief, it is the ability to emotionally respond to the demands of an experience in a manner that is socially normative. Furthermore, the person must demonstrate enough flexibility to willfully permit or deny spontaneous reactions to that experience such that dysfunction does not occur (non-pathological response) [2]. There is a significant association between an inability to do this—emotional dysregulation, and mental disorders for which a disturbance in mood is their primary feature (mood disorders) [3, 4].

In the process of formulating a differential diagnosis , clinicians are often readily alerted to the importance of evaluating for organic causes of new psychiatric presentations, such as depression or anxiety, when they correlate with the onset or exacerbation of a general medical condition. However, sometimes emotional dysregulation is the only harbinger of an insidious mood disorder that may be present or emerging. Irritability and emotional lability are two major components of emotional dysregulation and subsequently mood dysregulation to be vigilant for in all patients [5, 6]. Mood and anxiety disorders often coexist with medical conditions, and practically all psychiatric symptoms can be mimicked by a general medical condition. In some patients these disorders can contribute to the medical condition, whereas for others the medical condition is the underlying cause. It is important to be aware that symptoms of depression, irritability, mood lability , and anxiety can be prodromal of medical illness that if not uncovered early, could lead to significant morbidity and mortality.

For instance, in patients with carcinoma of the pancreas, symptoms of depression (affecting 38% to 45% of patients) and anxiety (affecting about 12% of patients) are among the earliest disease manifestations [7]. Endocrine tumors producing adrenaline such as pheochromocytomas are often heralded by panic attacks, anxiety, and irritability [8, 9]. Physical symptoms of hyperthyroidism such as sensitivity to heat, weight loss, restlessness, and sleeping difficulty can mimic an anxiety disorder, and irritability can also be an early disease manifestation [10]. Untreated streptococcal infection may lead to the onset of movements/tics called Sydenham’s chorea. In studies of children with Sydenham’s chorea , they exhibited obsessive-compulsive symptomatology, increased emotional lability, motoric hyperactivity, irritability, distractibility, and age-regressed behavior [11]. It is well known that irritability, anxiety, depression, dementia, and psychosis are associated with vitamin B12 deficiency [12]. Head injuries can cause post-concussive symptoms that develop within days of the incident and can last anywhere from a couple of days to a few months. These symptoms can mimic depression, anxiety, and attention-deficit disorders [13]. School failure, cognitive loss, hyperactivity, aggression, inattention, distractibility, and delinquent behaviors have all been reported with lead poisoning [14]. There truly is a myriad of general medical conditions associated with, and producing, psychiatric symptoms.

With this in mind, clinicians have an important role in managing the complete care of their patients. Patients with general medical conditions and associated psychiatric symptoms often suffer twice. MEND A MIND is a well-known useful mnemonic for ensuring a broad differential for organic causes of psychiatric presentations and can aid the clinician when evaluating a patient [15]. The mnemonic, which is slightly modified here to consider drugs/intoxication before degenerative causes (given the rarity in children) stands for: Metabolic/endocrine, Electrical (seizures) Neoplastic, Drugs/intoxication, Arterial/venous, Mechanical (trauma), Infectious/inflammation, Nutrition, Degenerative. The following table lists common organic causes of mood disturbance in order of the mnemonic, and provides general (by no means exhaustive) workup approaches to evaluation. The table applies to adults as well as children, but there is an emphasis here on the pediatric population with ADHD. See Table 3.1.

Table 3.1 Organic causes of mood disturbance in children and adults with ADHD
Full size table