The role of the insula in schizophrenia

Abstract

Involvement of the insular cortex is a common finding in neuroanatomical studies of schizophrenia, yet its contribution to disease pathology remains unknown. This review describes the normal function of the insula and examines pathology of this region in schizophrenia. The insula is a cortical structure with extensive connections to many areas of the cortex and limbic system. It integrates external sensory input with the limbic system and is integral to the awareness of the body's state (interoception). Many deficits observed in schizophrenia involve these functions and may relate to insula pathology. Furthermore, reports describing deficits caused by lesions of the insula parallel deficits observed in schizophrenia. Examples of insula-related functions that are altered in schizophrenia include the processing of both visual and auditory emotional information, pain, and neuronal representations of the self. The last of these functions, processing representations of the self, plays a key role in discriminating between self-generated and external information, suggesting that insula dysfunction may contribute to hallucinations, a cardinal feature of schizophrenia.

Does the salience network play a cardinal role in psychosis? An emerging hypothesis of insular dysfunction

“…In this regard, the insular cortex has emerged in recent times as a key brain region with consistent structural alterations in both schizophrenia and bipolar disorder. 1 Despite recent attempts to delineate the role of the insula in various neuropsychiatric disorders, including schizophrenia, [2][3][4] an integrative model of insular dysfunction in relation to psychosis is lacking.…”

Cigarette smoking is associated with thinner cingulate and insular cortices in patients with severe mental illness

“…4,24,25 Reduced grey matter in these regions has also been demonstrated in studies of unmedicated patients with psychosis. 26,27 In patients with bipolar disorder, reductions in the ACC and DLPFC 6,28 and the OFC 8 have been reported.…”

The Insula: An Underestimated Brain Area in Clinical Neuroscience, Psychiatry, and Neurology

“…Beyond mood disorders, the insula deficits in abnormal subjective feelings seem to underlie many other conditions that include mood-associated dimensions in their pathologies. For example, structural and functional deficits in the insula have been implicated in anxiety disorders [43,44], in schizophrenia for disturbed affective processing [45], in psychopathy for abnormal social emotion processing such as empathetic pain processing [46], and in anorexia nervosa for distorted subjective feelings of one's body [47]. Insula pathology has also been implicated in neurological disorders, including Huntington's disease and multiple sclerosis for impaired processing of facial emotions [48], and Alzheimer's disease for the loss of sense of self [49].…”