Schizophrenia is not a progressive brain disease

DSC_0072 1 (2)Despite Emil Kraepelin’s early characterization of dementia praecox, the disorder or disorders that we now call schizophrenia are not characterized by dementia, or inevitable loss of cognitive ability and function. Dr. Robert B. Zipursky, Professor of Psychiatry and Behavioural Neurosciences at McMaster University in Hamilton, Ontario, said that psychiatrists may share Kraepelin’s impression of a malignant illness because of the clinician’s illusion, which arises from the biased sample of patients that psychiatrists treat, i.e. people with chronic, relapsing illness and multiple co-morbidities who come to hospitals (1). According to Professor Zipursky, who spoke at the 9th Annual Pacific Psychopharmacology Conference in Coquitlam, BC on September 18, 2015, available studies indicate that about 70% of people with first-episode psychosis will achieve remission within a year; he defined remission as having positive symptoms no greater that mild in severity and negative symptoms no greater than moderate in severity.

First-episode psychosis includes patients with various diagnoses including bipolar disorder, schizoaffective disorder, brief psychotic disorder as well as schizophrenia. Patients who achieve functional recovery, however, represent a smaller group, especially in those confirmed to have schizophrenia. In long-term outcome research, 20% or fewer of people with schizophrenia meet criteria for recovery defined as sustained remission of symptoms and success in social relations and competitive employment.
Some psychiatrists have concluded that this long-term functional impairment is due to progressive cognitive deterioration which may occur with untreated or chronic positive psychotic symptoms. A related hypothesis is the “neurotoxicity of psychosis” which posits that persisting psychosis leads to ongoing loss of cerebral tissue as manifested by enlarged ventricles and cortical atrophy on neuroimaging, accompanied by worsening deficits on neuropsychologic testing. Consequently, many clinicians working in first episode psychosis accept that the duration of untreated psychosis is an important determinant of long-term outcome.

While he acknowledged that deficits in grey matter volumes observed with MRI are more prominent in chronic patients, Dr. Zipursky asserted that many factors may contribute to this such as sampling bias; concurrent substance use including cannabis, tobacco and alcohol; lack of physical activity; and chronic antipsychotic therapy. The latter is controversial, but he cited a meta-analysis of longitudinal MRI studies in which change in grey matter volumes was correlated with antipsychotic exposure but not illness duration or severity (2). However, he emphasized that relieving suffering and improving function are the goals of treatment, not specifically increasing cerebral volume, which is affected by various factors mentioned before. Furthermore, Dr. Zipursky showed compelling evidence that following a first episode of schizophrenia, antipsychotic discontinuation is by far the most important cause of relapse.

Duration of untreated psychosis (DUP) has a small correlation with treatment outcome, likely accounting for less than 5% of the variance in clinical outcome measures, and questionable association with cognitive functioning and structural brain measures, according to Dr. Zipursky. He presented evidence that it is a risk marker for poor outcome in schizophrenia as opposed to a causative risk factor. “It’s not certain that it relates to improving outcomes, but it does relate to reducing suffering,” Zipursky said.
He concluded that to improve outcomes and promote functional recovery, antipsychotic medication is crucial but so are psychosocial interventions to manage substance use, educate families, provide adequate housing and income support when needed, and engage patients in vocational rehabilitation and supported employment.


Zipursky RB, Reilly TJ, Murray RM. The myth of schizophrenia as a progressive brain disease. Schizophr Bull. 2013;39:1363-1372. Full text

Fusar-Poli P, Smieskova R, Kempton MJ, Ho BC, Andreasen NC, Borgwardt S. Progressive brain changes in schizophrenia related to antipsychotic treatment? A meta-analysis of longitudinal MRI studies. Neurosci Biobehav Rev. 2013;37:1680-1691. Full text

Could grey matter loss in the superior temporal gyrus contribute to treatment resistance?

The DSM 5 abandoned classifying schizophrenia by psychopathology subtype, but the heterogeneity of the disorder still requires explanation. A more pragmatic approach advocated by some researchers is classification according to treatment response: antipsychotic responsive, clozapine responsive, and clozapine non-responsive. Investigators are looking at the biologic correlates of these subtypes, and a group from New Zealand recently examined differences in brain volume. Using a 3-Tesla scanner, they obtained T1-weighted images of the brains of 18 antipsychotic responders, 19 clozapine responders (for whom other antipsychotics failed), 15 clozapine nonresponders, and 20 controls. All subjects were 18 to 45 years old, and patients with neurologic or active addictive disorders were excluded. The clozapine responsive and non-responsive patients had failed to respond to at least two trials of other antipsychotics, and the PANSS was used to assess symptoms.

The groups of patients did not differ by mean age, PANSS scores or illness duration. The groups had some differences in substance use history; the clozapine-resistant patients had more use of hallucinogens, and the antipsychotic responsive group had more use of cannabis, but the groups did not differ in stimulant use history.

Compared with controls, all patient groups had a reduction in whole-brain and white-matter volumes, and the clozapine-resistant group had a significant increase in ventricular volume. The treatment-resistant and clozapine-resistant patients had smaller grey matter volumes compared with controls and antipsychotic-responsive patients. In analysis using voxel-based morphometry, a technique to examine the volume of specific brain regions, the clozapine-resistant patients, compared with controls, showed bilateral grey matter reductions in the superior and middle temporal gyri, ventromedial prefrontal cortex, anterior cingulate gyrus, and postcentral gyrus. The left cerebellum and right occipital cortex also showed grey matter reduction. Compared with controls, the treatment-resistant group had a similar magnitude of grey matter volume reduction which especially affected the right perisylvian region.

Compared with the antipsychotic-responsive group, both clozapine-resistant and clozapine-responsive groups had reduction in grey matter volume with somewhat differing patterns. Only the clozapine-resistant patients had a relative reduction in the left cerebellum and left anterior cingulate gyrus. No differences were seen in comparing the clozapine-resistant and clozapine-responsive groups.

A controversy in the field of neuroimaging of schizophrenia is the role of antipsychotic exposure in cerebral volume loss; previous research has shown conflicting results. In this study, the clozapine-resistant group had a higher mean daily dose of antipsychotic compared with the other groups, but the researchers found no overall correlation between daily dose and grey matter volume. The study did not look at lifetime antipsychotic exposure.

The investigators highlight the finding of prominent volume reduction in the superior temporal gyrus in the clozapine-resistant group, which was seen in a number of prior studies including longitudinal investigations and in first-episode patients. This brain structure is crucial for auditory processing and language, which are highly implicated in schizophrenia; perhaps tissue loss in this region contributes to poor medication response. However, as the researchers state, in this kind of observational study we are unable to draw conclusions about cause and effect.

Anderson VM, Goldstein ME, Kydd RR, Russell BR. Extensive grey matter volume reduction in treatment-resistant schizophrenia. Int J Neuropsychopharmacol. Published online Feb 25, 2015. Abstract

Reduction in cortical thickness in treatment-resistant schizophrenia

Reduced grey-matter volume and cortical thickness are well documented in people with schizophrenia, but few studies have examined structural changes in treatment-resistant schizophrenia (TRS). In this study from Brazil, the researchers examined cortical thickness by means of MRI volumetrics in three groups: 61 patients with TRS, 67 patients with non-TRS, and 80 unaffected controls (1). The mean age of all subjects was about 34 years and two-thirds were men. The mean PANSS score of the TRS group was 63.4, significantly greater than the mean score of the non-TRS group which was 54.6. Of the TRS patients, 72% were receiving clozapine whereas the majority of non-TRS patients were receiving either olanzapine, quetiapine, or risperidone.

In comparison with the control group, the TRS group had significant reduction in cortical thickness in four regions of the right hemisphere, including the precentral, middle temporal, and lateral occipital gyri; and six regions of the left hemisphere, including the middle temporal, middle frontal, lateral orbitofrontal, and superior temporal gyri. In comparing the TRS and non-TRS groups, the investigators found a significant reduction in thickness of the left dorsolateral prefrontal cortex in the TRS patients, even when controlling for duration of illness and dose of medication.

The investigators cite existing research suggesting that dysfunction of the dorsolateral prefrontal cortex, which is associated with working memory in healthy subjects, may correlate with poor treatment response. For instance, a 2003 study found that greater cortical volume in this region predicts good response to clozapine (2). Studies that examine the dynamics of volume loss prospectively might help determine the correlates of regional cortical thinning in TRS.

1. Zugman A, Gadelha A, Assuncao I, et al. Reduced dorso-lateral prefrontal cortex in treatment resistant schizophrenia. Schizophr Res. 30 May 2013. doi: 10.1016/j.schres.2013.05.002. [Epub ahead of print] Abstract

2. Molina V, Reig S, Sarramea F, et al. Anatomical and functional brain variables associated with clozapine response in treatment-resistant schizophrenia. Psychiatry Res. 2003;124(3):153-161. Abstract