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Apathy and depression are the most frequent neuropsychiatric symptoms in Alzheimer's disease (AD). In a cross-sectional observational study of 734 subjects with probable mild AD, we evaluated the prevalence of apathy and depression. After the use of specific diagnostic criteria, we tested the interaction between the two syndromes and their relation with specific comorbidities, and different functional outcomes. Depression was diagnosed using the diagnostic criteria for depression in AD, and apathy with the diagnostic criteria for apathy in neuropsychiatric disorders. According to the specific diagnostic criteria, depression had a 47.9% prevalence, while apathy prevalence was 41.6%. Apathy and depression were associated in 32.4% of patients (n = 225). 9.4% (n = 65) had only apathy, 15.4% (n = 107) had only depression, and 42.9% had no apathy and no depression (n = 298). The three most frequent depressive symptoms were fatigue or loss of energy (59.4%), decreased positive affect or pleasure in response to social contacts and activities (46.2%), and psychomotor agitation or retardation (36.9%). Concerning apathy, loss of goal-directed cognition was the most frequently altered (63.6%), followed by loss of goal-directed action (60.6%) and loss of goal-directed emotion (43.8%). Patients with both apathy and depression more frequently required a resource allowance for dependency. Neurological comorbidities were more frequent in the "apathy and depression" and "depression alone" groups (p < 0.001). Apathy and depression overlap considerably, and this might be explained by the presence of some non-specific symptoms in both diagnostic criteria. The need for social support is higher when a patient fulfills the two diagnostic criteria.

Auditory verbal hallucinations are a cardinal symptom of schizophrenia. Bleuler and Kraepelin distinguished 2 main classes of hallucinations: hallucinations heard outside the head (outer space, or external, hallucinations) and hallucinations heard inside the head (inner space, or internal, hallucinations). This distinction has been confirmed by recent phenomenological studies that identified 3 independent dimensions in auditory hallucinations: language complexity, self-other misattribution, and spatial location. Brain imaging studies in schizophrenia patients with auditory hallucinations have already investigated language complexity and self-other misattribution, but the neural substrate of hallucination spatial location remains unknown. Magnetic resonance images of 45 right-handed patients with schizophrenia and persistent auditory hallucinations and 20 healthy right-handed subjects were acquired. Two homogeneous subgroups of patients were defined based on the hallucination spatial location: patients with only outer space hallucinations (N 5 12) and patients with only inner space hallucinations (N 5 15). Between-group differences were then assessed using 2 complementary brain morphometry approaches: voxel-based morphometry and sulcus-based morphometry. Convergent anatomical differences were detected between the patient subgroups in the right temporoparietal junction (rTPJ). In comparison to healthy subjects, opposite deviations in white matter volumes and sulcus displacements were found in patients with inner space hallucination and patients with outer space hallucination. The current results indicate that spatial location of auditory hallucinations is associated with the rTPJ anatomy, a key region of the ''where'' auditory pathway. The detected tilt in the sulcal junction suggests deviations during early brain maturation, when the superior temporal sulcus and its anterior terminal branch appear and merge.