Pain Insensitivity in Schizophrenia: A Neglected Phenomenon and Some Implications

Abstract

The literature on insensitivity to pain in schizophrenia is reviewed. Numerous reports indicate that, relative to normals, individuals with schizophrenia are insensitive to physical pain associated with illness and injury. In addition, insensitivity to pain of various sorts administered in experimental studies has been reported frequently in this population. This extensive and diverse literature of clinical and experimental reports suggests that many individuals with schizophrenia are less sensitive to pain than normal individuals. However, because the experimental studies--almost all of which were conducted before 1980--suffer from a variety of methodological limitations, this research provides neither a satisfactory characterization nor an adequate explanation of pain insensitivity in schizophrenia. It is argued that this widely reported but currently neglected phenomenon has important implications for physical health, self-mutilation, homelessness, premorbid development, and affective flattening in individuals with schizophrenia.

Alterations in Behavioral Responses to a Cholinergic Agonist in Post-Pubertal Rats with Neonatal Ventral Hippocampal Lesions: Relationship to Changes in Muscarinic Receptor Levels

“…Some of the physical symptoms of schizophrenia described by Kraepelin (1919) included diminished sensitivity to pain, increased secretion of saliva, tremor, seizures, and lower body temperature (Kraepelin, 1919). In addition, recent studies have reported that schizophrenic patients often develop thermoregulatory disturbances (Shiloh et al, 2001) and have increased pain threshold (Dworkin, 1994;Lautenbacher and Krieg, 1994).…”

Dissociation and pain perception: An experimental investigation

“…For example, individuals with bulimia nervosa were found to have higher pain thresholds in response to both thermal pain stimulation (TPS) and submaximal effort tourniquet test (SETT) than normal controls (de Zwaan, Biener, Bach, Wiesnagrotzki, & Stacher, 1996;de Zwaan, Biener, Schneider, & Stacker, 1996), and similar results were found for individuals with a history of bulimia nervosa whose symptoms were in remission (Stein et al, 2002). Decreased sensitivity to experimentally induced pain has also been reported among individuals with schizophrenia (Blumensohn, Ringle, & Eli, 2002;Dworkin, 1994), and major depression (Dworkin, Clark, & Lipsitz, 1994). In a meta-analysis and review of pain perception and major depression, Dickens, McGowan, and Dale (2003) reported that depressed subjects were less likely to perceive sensory stimuli as painful relative to nondepressed subjects.…”

Food Intake and Reward Mechanisms in Patients with Schizophrenia: Implications for Metabolic Disturbances and Treatment with Second-Generation Antipsychotic Agents

“…This and other aberrations in protective mechanisms afforded by the pain system, noted in a number of reports Evans, 1980;Davis and Buchsbaum, 1981;Fishbain, 1982;Bickerstaff et al, 1988;Rosenthal et al, 1990;Dworkin, 1994;Kudoh et al, 2000;Torrey, 2002), some of which date back to the days of Haslam (Haslam, 1798;1809cited in Torrey, 2002, Kraepelin (Kraepelin, 1919cited in Hooley and Delgado, 2001), and Bleuler (Bleuler, 1924cited in Hooley and Delgado, 2001, could be yet another aspect of excessive/altered endogenous opioid function in schizophrenia Davis and Buchsbaum, 1981;Davis, 1983;Wiegant et al, 1992). Such a notion is supported clinically by reversal of pain insensitivity by opioid antagonism and by molecular abnormalities in specific opioid genes, for example, prodynorphin (Ventriglia et al, 2002) or proenkephalin (Mikesell et al, 1996) in schizophrenic patients.…”