The most common psychiatric disorders in which memory impairment may be seen are schizophrenia, depression, and anxiety. The objective cognitive impairment is often mild with alterations in such functions as attention, STM, and speed of processing. Examination of memory biases for disorder-congruent information suggests that characteristic cognitive styles can distinguish among various psychopathologies. For example, an implicit memory bias has been typically associated with anxiety and an explicit memory bias has been found to be more characteristic of depression (Williams et al., 1997). Implicit memory processes activate stored information, thereby improving its accessibility though not necessarily affecting its direct retrievability. Conversely, explicit memories involve conscious, deliberate recall of information that was elaborated at the time of encoding and are therefore more available due to embellishment from contextual cues. Anxiety is marked by a non-conscious, automatic, preattentive bias towards threat cues that may

prime such information in implicit memory tests (Mathews et al., 1989). However, this defensive attentional mechanism thwarts further processing of anxiety-provoking stimuli and so no explicit memory bias appears for such material. In contrast, depression is characterised by conscious elaboration of sad material that increases its availability for explicit directed recall. However, these specific memory effects in anxiety may not generalise across diagnostic categories. Although the hypothesis of an implicit but not explicit memory bias for disorder-congruent material has been replicated in generalised anxiety disorder (GAD), others have found both implicit and explicit memory biases for relevant stimuli in panic disorder (Cloitre & Leibowitz, 1991; MacLeod & McLaughlin, 1995). Methodological inconsistencies across studies might account for these discrepant memory effects (Becker et al., 1999).