Free Secondary Schizophrenia by Perminder S. Sachdev

for those with unipolar disorder (23% bipolar abuse. Of the 74 patients with organic psychosis, 25
    mixed, 11% bipolar manic, 11% bipolar depressed, and had visual hallucinations compared with 13 with audi-6% unipolar vs. 61% schizophrenia). As in schizophre-tory hallucinations. In subjects with schizophrenia the 22
    nia, in bipolar disorder, auditory hallucinations were frequencies were reversed – 25 patients had auditory Chapter 3 – Secondary hallucinations
    hallucinations and 12 had visual hallucinations [24].
    laden experience. However, such a one-dimensional Additionally,
    first-rank
    auditory
    hallucinations
    model does not capture the full range of possible occurred in 22% of patients with schizophrenia and abnormal visual experiences that occur across a range only 4% of patients with organic disorders. In contrast, of functional and organic disorders, such as poly-a study by Johnstone and colleagues on 328 recently olpia/pallinopsia – where true percepts are experi-admitted psychotic patients – 23 of whom had under-enced multiple times – or metamorphopsia, where true lying organic disorder – failed to demonstrate major percepts are dimensionally altered; each of these could phenomenological differences between patients with be considered both an illusion and a hallucination primary psychiatric disorders and those with organic [27]. Additionally, the distinction between hallucina-disease in a manner that would allow such differences tion and pseudohallucination has been driven by an to stand as mainstays in the differential diagnosis of assessment of the sufferer’s attribution – external ver-these two sets of disorders [25] . This study highlights sus internal, “like” a true percept versus “is” a true per-the fact that astute clinic judgement is critical in deter-cept, or insight versus insightlessness; in reality, the mining if hallucinations are secondary to neurological sufferer’s experience is not so readily dichotomized, and other diseases or are due to psychiatric disorders.
    and it may be that the content and phenomenology of Although hallucinations may occur in a number of the experience is more closely tied to the underlying modalities within the one individual, it is useful to con-pathology than its associated experiential quality.
    sider them on a modality-by–modality basis, in view One model of visual hallucinations is provided of the differing etiological, biological, and treatment by ffytche and colleagues. They propose that visual facets associated with each type of hallucination.
    pathway disorders produce characteristic simple VHs, unfamiliar/malformed figures and landscape scenes, Secondary visual hallucinations
    whereas disorders involving the brainstem and/or cholinergic dysfunction result in familiar figures, ani-Throughout history, visual hallucinations (VHs) have mals, and frequent delusional elaboration. The clini-long been associated with concepts of insanity [26].
    cal utility of this model is supported by the fact that Like other forms of aberrant sensory experience, VHs the two groups tend to respond to different treatments can occur in healthy individuals, functional psychi-
    [27, 28] . Furthermore, we would argue that an under-atric disorders, and organic states. An understanding standing of the anatomy of visual experience, and how of their experience in the latter can inform an under-lesion location at least partially predicts phenomenol-standing of the neurobiology of mental disorders as ogy, leads to more appropriate investigation and man-well as the anatomy of normal human perception.
    agement of VHs syndromes [29].
    Spectrum of visual perceptual
    Visual hallucinations in normal
    disturbances
    individuals
    As in other sensory modalities, VHs have been con-Individuals in the community who experience VHs in sidered to fall at one extreme of a spectrum of per-the absence of a psychiatric or neurological disorder ceptual experience. This spectrum extends from