Sluggish Cognitive Tempo in ADHD

Attention deficit hyperactivity disorder (ADHD) is defined by three distinct subtypes:

• The predominantly inattentive type
• The predominantly hyperactive-impulsive type
• The combined type

Some individuals with the predominately inattentive type of ADHD also display a subset of symptoms that are typified by sluggish-lethargic behavior and mental fogginess. It is this subset of characteristics that have been described as "sluggish cognitive tempo" (or SCT).

Symptoms of SCT include:

• Drowsiness
• Frequent daydreaming
• Frequent staring into space
• Mental fogginess
• Poor memory retrieval
• Sluggish-lethargic behavior
• Slow processing of information
• Social passiveness, reticence, and withdrawal
• The tendency to become confused easily

People with SCT often have difficulty with problem-solving, self-organization, self-initiation, and processing competing sources of information. They are often characterized as hypoactive (less active).

SCT Symptoms and DSM History

The Diagnostic and Statistical Manual of Mental Disorders (DSM), published by the American Psychiatric Association, is the standard manual for assessment and diagnosis of mental disorders used by mental health professionals in the United States. The DSM lists various criteria required for diagnosis.

Symptoms of a sluggish cognitive style were first associated with ADHD in the third edition of the DSM, published in 1980. The DSM-III used the term "attention deficit disorder" (ADD) and expanded the understanding of the disorder, recognizing that impairments in attention can occur separately from impulsivity and hyperactivity.

Two subtypes were identified in the DSM-III: ADD with hyperactivity and ADD without hyperactivity. The subtype ADD without hyperactivity did not really reflect "pure inattention" as the name implies, because children still had to display significant problems with impulsivity.

Publication of a revised third edition of the DSM manual (DSM-III-R) in 1987 did not separate symptoms of inattention, impulsivity, and hyperactivity, addressing all three primary symptoms as a group. Two categories were identified—attention-deficit hyperactivity disorder and undifferentiated attention-deficit disorder.

In 1994, the fourth edition subdivided symptoms into two categories—inattention and hyperactivity/impulsivity. The three current subtypes of ADHD were identified—predominantly inattentive type, predominantly hyperactive-impulsive type, and the combined type.

Understanding Inattention and SCT

Inattention is often reflective of distractibility. Current diagnostic criteria for the inattention associated with ADHD include:

• Often does not give close attention to details or makes careless mistakes at work, in schoolwork, or other activities
• Often has trouble sustaining attention in tasks or activities
• Often does not seem to listen when spoken to directly
• Often does not follow through on instructions; starts tasks but quickly loses focus and is easily sidetracked; fails to finish schoolwork, household chores, or tasks in the workplace
• Often has difficulty organizing tasks and activities
• Often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort
• Often loses things needed for tasks and activities (such as school assignments, pencils, books, keys, wallet, glasses, paperwork, etc.)
• Is often easily distracted by extraneous stimuli
• Is often forgetful in daily activities, chores, etc.

Children and adults with the sluggish cognitive tempo (SCT) cluster of symptoms tend to display a different kind of inattention that has more of a daydreamy, hypoactive, and passive feel, as opposed to a distractible quality. Individuals with SCT tend to exhibit less overt, externalizing symptoms, and more internalizing symptoms of anxiety, depression, social withdrawal, and more information-processing deficits.