Schizophrenia Research Trends

The Association of Verbal Learning Deficits with Unawareness of Mental Disorder 165AWARENESS OF ILLNESS ANDNEUROCOGNITION IN SCHIZOPHRENIAThree main theories are most often described in the literature regarding the etiology ofpoor insight in schizophrenia. Firstly, according to the psychodynamic approach, poor insightis a denial of illness, it is a defense mechanism protecting against low self-esteem. Secondly,"clinical" hypotheses have been proposed that unawareness of mental disorder is amanifestation of other groups of symptoms or, alternatively, it is an independent basicsymptom arising directly from the illness process. Finally, the neuropsychological view hasbeen developed which assumes that poor insight is a function of neurocognitive deficits [cf.Carroll et al., 1999; Cuesta and Peralta, 1994; Macpherson, Jerrom, and Hughes, 1996; Smithet al., 2000].The neuropsychological theory draws a parallel between unawareness of illness inschizophrenia and poor insight described in some neurological conditions. Lack of insighthas been evidenced in lesions in the frontal lobe of right hemisphere. Many authors have alsopointed out a clinical resemblance of the syndrome of "anosognosia" in parietal lobe disorderand lack of insight in schizophrenia [e.g., Cuesta and Peralta, 1994; Cuesta et al., 1995; Leleand Joglekar, 1998]. Some studies have searched for the relationship between unawareness ofillness and neuroanatomical measures. Flashman et al. [2000], using a structural magneticresonance imaging, have found that patients with schizophrenia who were unaware of theirsymptoms had smaller brain size and intracranial volume than patients with schizophreniawith good insight, however, these results have been not confirmed by Rossell et al. [2003].Most investigators focused on associations between lack of insight and frontaldysfunction indexed by Wisconsin Card Sorting Test (WCST). However, these studies haveyielded inconsistent findings, with number of studies which found [e.g., Lysaker et al., 1998,2002; Marks et al., 2000; Mohamed et al., 1999; Rossell et al., 2003; Smith et al., 2000;Voruganti, Heslegrave, and Awad, 1997; Young et al., 1998; Young, Davila, and Scher,1993] and which did not find [e.g., Arduini, Kalyvoka, and Stratta, 2003; Collins et al., 1997;Cuesta et al., 1995; McEvoy et al., 1996] significant relationship between performance onWCST and insight scores [cf. Drake and Lewis, 2003].A group of studies has found a modest association between general cognitive ability andawareness of illness [e.g., Rossell et al., 2003; Young et al., 1998; cf. Kemp and David, 1996;Macpherson, Jerrom, and Hughes, 1996b]. Some reports have investigated relationshipbetween insight and memory impairments in patients with schizophrenia. They found nosignificant relationship between insight scores and Rivermead Behavioural Memory Test[Carroll et al., 1999], memory score from Luria Nebraska Neuropsychological Battery[McCabe et al., 2002], California Verbal Learning Test [Smith et al. 2000], measures ofworking memory [Rossell et al., 2003], and a global memory index based on Hopkins VerbalLearning Test (HVLT) and two subtests from Wechsler Memory Scale-Revised [Lysaker etal., 1998]. Significant relationships were found only in two studies, that is in a study byMarks et al. [2000], between worse performance on immediate recall in HVLT and denial ofpresence of illness and, in opposite direction, between better performance on immediaterecall and lack of insight in study conducted by Cuesta and Peralta [1994].