Differential Diagnostic Process in the Case with SCT
Many literature data point out that SCT is in less association with externalizing disorders (i.e. disruptive behavioral disorders), whereas more associated with internalizing disorders (i.e. anxiety, depression) as opposed to ADHD (2, 21 – 23). In our case, no evidence was found to suggest the presence of oppositional defiant disorder or conduct disorder. But, especially at the beginning of clinical follow-up, the presence of anxiety symptoms such as not being able to go to the toilet alone and the fear of darkness is a condition that is consistent with the literature and is expected. However, there were no additional signs of anxiety disorder to diagnose the patient. Depression can accompany SCT as an internalizing symptom dimension, too. However, there was not enough evidence to clinically diagnose the case with major depression. The case was moving slowly and had low energy. These findings may perhaps be confounded with the ”anergia” symptom of depression. Even if it was accepted as anergia, the presence of ”anergia” alone would not adequately explain the depression of the case.
It was also noted that the patient did not immediately look when his name was called, especially around 6 years of age. Hence, a possible ASD diagnosis was investigated in the case. However, the lack of any findings of the case in language, social communication and empathy fields that support ASD diagnosis has kept us away from considering ASD. The relationship between ASD and SCT was first examined in a current study and SCT symptoms were found to be significantly higher in adolescent cases with ASD (24). An up-to-date study in young adults with ASD found that one-third of these cases had high levels of SCT symptoms (25). The coexistence of these two psychopathologies may be associated with a possible similarity or overlap between their symptoms. Since the ”processing speed slowness” observed in SCT can also be observed frequently in individuals with intellectual disability, it is important to distinguish these two different psychopathological structures. For this purpose, we wanted to measure the intelligence capacity of the case, applying WISC-R, and finding that the patient had a normal estimated IQ score and had no mental insufficiency.
The case has inattention symptoms that do not affect his daily functionality. Moreover, according to both psychiatric examinations conducted on DSM-5 diagnostic criteria and K-SADS-PL clinical interviews, the patient had subthreshold symptoms of inattentive presentation of ADHD. One study found that 44-54% of patients with SCT had ADHD diagnosis, 27-35% of patients with ADHD had SCT characteristics, and 28-46% of children with SCT present an independent phenotype not having ADHD or depression diagnoses (26).