Attentional problems are among the most ubiquitous and nonpathognomonic of psychiatric complaints. Nearly all psychiatric disorders impact cognitive functioning in one form or another, and it can be a challenge for clinicians to differentiate free-standing disorders of cognition (e.g., adult ADHD or dementia) from those that are iatrogenic (due to psychotropic or nonpsychotropic medications) or the epiphenomena of other conditions (such as depression, mania, anxiety, or schizophrenia). Cognitive problems involve distinct domains that can form unique constellations and present differently from one psychiatric disorder to another (e.g., skip ahead to Table 21.2). Sometimes they may be just one facet of a more complex, heterogeneous phenotype. Consequently, pharmacotherapies for cognitive problems in one disorder (say, dementia) may not so neatly extrapolate to those of another (say, ADHD). Cognitive problems may be profound and all-encompassing (as in dementia, some developmental disorders, or schizophrenia), artifactual (as in depression-related cognitive dysfunction (formerly called pseudodementia)), or subtle (as might occur in anxiety disorders or high-functioning patients with mood disorders).