Schizophrenia News: Cognitive Deficit Syndrome

This SharePost is the first of a two-part series and examines a greatly disabling symptom of schizophrenia: cognitive deficit. I quickly realized my near-photographic memory was not the norm. My psychiatrist told me, "Cognitive deficit is seen by leading schizophrenia researchers as the true hallmark of the illness." Unlike hearing voices whose role has been well-documented as a classic symptom, cognitive impairment wasn't considered to be significant until recently.

Ronan O'Carroll, professor of psychology at the University of St. Andrews (St. Andrews, Fife, Scotland) has for the past 10 years collaborated with colleagues investigating this topic. He maintains that over the past 25 years, it has become evident that "marked cognitive impairment is, in fact, the norm and often predates the illness."

Research findings detail:

• A wide range of cognitive functions are affected, particularly memory, attention, motor skills, executive function and intelligence.

• The cognitive impairment often pre-dates the illness onset.

• It is an intrinsic part of the illness and is observed in young, drug-naïve patients.

• Cognitive impairment is related to social and functional outcome.

A random sample of 5,000 births in England, Scotland and Wales during the first week of March 1946 corroborates the prior onset theory. Out of this sample, 30 cases of schizophrenia arose between the ages of 16 and 43. Non-verbal, verbal and reading abilities were tested at the ages of 8, 11 and 15 years and arithmetic was measured at the ages of 11 and 15 years. The children who developed schizophrenia in later life were significantly impaired on non-verbal and verbal intelligence tests from the age of 8, and on arithmetic skills from the age of 11.

Studies have shown mixed results as to whether cognitive impairment is progressive after the onset of the illness, yet the real-life consequences are all too traumatic to people experiencing deficits. One study showed cognitive impairment predicted over 40 percent of the variance in scores on a functional needs-assessment rating scale. Another study of 80 outpatients with schizophrenia revealed better cognitive flexibility and verbal memory were positively associated with interpersonal problem-solving ability.

As those of us intimately affected know, negative symptoms and cognitive deficit are not responsive to the atypicals. If the drugs offer some modest hope, they have yet to be seen as altering cognitive status greatly in the long-term.

As early as November 2001, a Psychiatric News article documented imaging studies (MRI scans) conducted over a five-year period on the brains of 12 teenagers diagnosed with schizophrenia. The subjects lost gray matter over the five-year period. First the parietal lobes were affected, then the temporal lobes, frontal lobes and frontal eye fields.

Gray matter loss, according to Paul Thompson, one of the researchers, appeared to be a true reflection of disease promotion: "Patients with the worst disease symptoms also had the greatest amount of gray matter loss." According to the article, severity of auditory hallucinations was linked to the severity of gray-matter loss in the temporal lobes.