Sluggish cognitive tempo - Wikipedia, the free encyclopedia
Sluggish Cognitive Tempo (SCT) is a descriptive term which is used to better identify what appears to be a homogeneous group within the Predominantly Inattentive Type (ADHD/PI) DSM-IV classification. Those with SCT show a qualitatively different kind of attention deficit more typical of a true information input and output problem, than from those who have had a significant history of hyperactivity-impulsivity. SCT children show lower selective attention, sustained focus, and have memory retrieval problems more typical of a learning disability profile. They are also HYPO-active and are sluggish mentally and physically.
SCT is qualitatively different from classic ADHD
In many ways those who have an SCT profile have the opposite symptoms of those with classic ADHD. They also don't have the same risks and outcomes. Instead of being hyperactive, social, extroverted, and overly talkative, those with SCT are hypoactive, passive, and shy. Their demeanor is sluggish and they logically also process information more slowly. Conversly those with classic ADHD are more impatient, ancy, and have no difficulty processing information. A key behavioural characteristic of those with SCT characteristics is that they are more likely to be lacking motivation. They lack energy to deal with mundane tasks and will consequently seek things that are mentally stimulating because of their underaroused state. Conversely, those with the other two subtypes of ADHD are characteristically more impulsive, distracted, and have low goal persistence.
Selective attention difficulties of those with SCT manifests itself academically, in that they are prone to making more mistakes while working. Those with classic ADHD do not have this difficulty. Those with SCT have difficulty with verbal retrieval from long term memory, and also have greater visual spatial deficits. They have deficits in working memory which has been described as the ability to keep multiple things in mind for manipulation, while keeping this information free from internal distraction. Consequently, mental skills such as calculation, reading, and abstract reasoning are often more challenging for those with SCT. They also have a more disorganized thought process, a greater degree of sloppiness, and lose things more easily. They tend to have a greater degree of comorbid learning disabilities. Instead of having greater difficulty selecting and filtering sensory input as is in the case of SCT, people with ADHD/C and ADHD/PHI, have problems with inhibition.
Studies indicate that Comorbid psychiatric problems are more often of the internalizing variety with SCT, such as anxiety, depression, and social withdrawal. Their typical shy nature and slow response time has often been misinterpreted as aloofness or disinterest by others. In social group interactions those with SCT may be ignored. Those with the other types of ADHD are more likely to be rejected in social situations because of more intrusive or aggressive behaviour. Those with classic ADHD also show externalizing problems such as substance abuse, oppositional-defiant disorder, and, to a lesser degree, conduct disorder.  
Finally a vast majority of those with classic ADHD clinically respond to stimulant medication with significant reductions in symptoms. Only a minority of those with an SCT profile respond clinically to stimulant medication.