Relapse duration, treatment intensity, and brain tissue loss in schizophrenia: a prospective longitudinal MRI study

OBJECTIVE

Longitudinal structural MRI studies have shown that patients with schizophrenia have progressive brain tissue loss after onset. Recurrent relapses are believed to play a role in this loss, but the relationship between relapse and structural MRI measures has not been rigorously assessed. The authors analyzed longitudinal data to examine this question.

METHODS

The authors studied data from 202 patients drawn from the Iowa Longitudinal Study of first-episode schizophrenia for whom adequate structural MRI data were available (N=659 scans) from scans obtained at regular intervals over an average of 7 years. Because clinical follow-up data were obtained at 6-month intervals, the authors were able to compute measures of relapse number and duration and relate them to structural MRI measures. Because higher treatment intensity has been associated with smaller brain tissue volumes, the authors also examined this countereffect in terms of dose-years.

RESULTS

Relapse duration was related to significant decreases in both general (e.g., total cerebral volume) and regional (e.g., frontal) brain measures. Number of relapses was unrelated to brain measures. Significant effects were also observed for treatment intensity.

CONCLUSIONS

Extended periods of relapse may have a negative effect on brain integrity in schizophrenia, suggesting the importance of implementing proactive measures that may prevent relapse and improve treatment adherence. By examining the relative balance of effects, that is, relapse duration versus antipsychotic treatment intensity, this study sheds light on a troublesome dilemma that clinicians face. Relapse prevention is important, but it should be sustained using the lowest possible medication dosages that will control symptoms.

MAPK14 and CNR1 gene variant interactions: effects on brain volume deficits in schizophrenia patients with marijuana misuse

BACKGROUND

Adolescent marijuana use is associated with increased risk for schizophrenia. We previously reported that marijuana misuse in conjunction with specific cannabinoid receptor 1 (CNR1) genetic variants (rs12720071-G-allele carriers) contributed to white-matter (WM) brain volume deficits in schizophrenia patients. In this study, we assessed the influence of another cannabinoid-related gene, mitogen-activated protein kinase 14 (MAPK14), and potential MAPK14-CNR1 gene-gene interactions in conferring brain volume abnormalities among schizophrenia patients with marijuana abuse/dependence. MAPK14 encodes a member of the MAPK family involved in diverse cellular processes, including CNR1-induced apoptosis.

METHOD

We genotyped 235 schizophrenia patients on nine MAPK14 tag single nucleotide polymorphisms (tSNPs). Approximately one quarter of the sample had marijuana abuse or dependence. Differential effects of MAPK14 tSNPs on brain volumes across patients with versus without marijuana abuse/dependence were examined using ANCOVA.

RESULTS

Of the MAPK14 tSNPs, only rs12199654 had significant genotype effects and genotype × marijuana misuse interaction effects on WM volumes. rs12199654-A homozygotes with marijuana abuse/dependence had significantly smaller total cerebral and lobar WM volumes. The effects of MAPK14 rs12199654 on WM volume deficits remained significant even after controlling for the CNR1 rs12720071 genotype. There were significant main effects of the MAPK14 CNR1 diplotype and diplotype × marijuana interaction on WM brain volumes, with both genetic variants having additive contributions to WM volume deficits only in patients with marijuana misuse.

CONCLUSIONS

Given that CNR1-induced apoptosis is preceded by increased MAPK phosphorylation, our study suggests that potential MAPK14-CNR1 gene-gene interactions may mediate brain morphometric features in schizophrenia patients with heavy marijuana use.

Progressive brain change in schizophrenia: a prospective longitudinal study of first-episode schizophrenia

BACKGROUND

Schizophrenia has a characteristic onset during adolescence or young adulthood but also tends to persist throughout life. Structural magnetic resonance studies indicate that brain abnormalities are present at onset, but longitudinal studies to assess neuroprogression have been limited by small samples and short or infrequent follow-up intervals.

METHODS

The Iowa Longitudinal Study is a prospective study of 542 first-episode patients who have been followed up to 18 years. In this report, we focus on those patients (n = 202) and control subjects (n = 125) for whom we have adequate structural magnetic resonance data (n = 952 scans) to provide a relatively definitive determination of whether progressive brain change occurs over a time interval of up to 15 years after intake.

RESULTS

A repeated-measures analysis showed significant age-by-group interaction main effects that represent a significant decrease in multiple gray matter regions (total cerebral, frontal, thalamus), multiple white matter regions (total cerebral, frontal, temporal, parietal), and a corresponding increase in cerebrospinal fluid (lateral ventricles and frontal, temporal, and parietal sulci). These changes were most severe during the early years after onset. They occur at severe levels only in a subset of patients. They are correlated with cognitive impairment but only weakly with other clinical measures.

CONCLUSIONS

Progressive brain change occurs in schizophrenia, affects both gray matter and white matter, is most severe during the early stages of the illness, and occurs only in a subset of patients. Measuring severity of progressive brain change offers a promising new avenue for phenotype definition in genetic studies of schizophrenia.

Cannabinoid receptor 1 gene polymorphisms and marijuana misuse interactions on white matter and cognitive deficits in schizophrenia

Marijuana exposure during the critical period of adolescent brain maturation may disrupt neuro-modulatory influences of endocannabinoids and increase schizophrenia susceptibility. Cannabinoid receptor 1 (CB1/CNR1) is the principal brain receptor mediating marijuana effects. No study to-date has systematically investigated the impact of CNR1 on quantitative phenotypic features in schizophrenia and inter-relationships with marijuana misuse. We genotyped 235 schizophrenia patients using 12 tag single nucleotide polymorphisms (tSNPs) that account for most of CB1 coding region genetic variability. Patients underwent a high-resolution anatomic brain magnetic resonance scan and cognitive assessment. Almost a quarter of the sample met DSM marijuana abuse (14%) or dependence (8%) criteria. Effects of CNR1 tSNPs and marijuana abuse/dependence on brain volumes and neurocognition were assessed using ANCOVA, including co-morbid alcohol/non-marijuana illicit drug misuse as covariates. Significant main effects of CNR1 tSNPs (rs7766029, rs12720071, and rs9450898) were found in white matter (WM) volumes. Patients with marijuana abuse/dependence had smaller fronto-temporal WM volumes than patients without heavy marijuana use. More interestingly, there were significant rs12720071 genotype-by-marijuana use interaction effects on WM volumes and neurocognitive impairment; suggestive of gene-environment interactions for conferring phenotypic abnormalities in schizophrenia. In this comprehensive evaluation of genetic variants distributed across the CB1 locus, CNR1 genetic polymorphisms were associated with WM brain volume variation among schizophrenia patients. Our findings suggest that heavy cannabis use in the context of specific CNR1 genotypes may contribute to greater WM volume deficits and cognitive impairment, which could in turn increase schizophrenia risk.

Long-term antipsychotic treatment and brain volumes: a longitudinal study of first-episode schizophrenia

CONTEXT

Progressive brain volume changes in schizophrenia are thought to be due principally to the disease. However, recent animal studies indicate that antipsychotics, the mainstay of treatment for schizophrenia patients, may also contribute to brain tissue volume decrement. Because antipsychotics are prescribed for long periods for schizophrenia patients and have increasingly widespread use in other psychiatric disorders, it is imperative to determine their long-term effects on the human brain.

OBJECTIVE

To evaluate relative contributions of 4 potential predictors (illness duration, antipsychotic treatment, illness severity, and substance abuse) of brain volume change.

DESIGN

Predictors of brain volume changes were assessed prospectively based on multiple informants.

SETTING

Data from the Iowa Longitudinal Study.

PATIENTS

Two hundred eleven patients with schizophrenia who underwent repeated neuroimaging beginning soon after illness onset, yielding a total of 674 high-resolution magnetic resonance scans. On average, each patient had 3 scans (≥2 and as many as 5) over 7.2 years (up to 14 years).

MAIN OUTCOME MEASURE

Brain volumes.

RESULTS

During longitudinal follow-up, antipsychotic treatment reflected national prescribing practices in 1991 through 2009. Longer follow-up correlated with smaller brain tissue volumes and larger cerebrospinal fluid volumes. Greater intensity of antipsychotic treatment was associated with indicators of generalized and specific brain tissue reduction after controlling for effects of the other 3 predictors. More antipsychotic treatment was associated with smaller gray matter volumes. Progressive decrement in white matter volume was most evident among patients who received more antipsychotic treatment. Illness severity had relatively modest correlations with tissue volume reduction, and alcohol/illicit drug misuse had no significant associations when effects of the other variables were adjusted.

CONCLUSIONS

Viewed together with data from animal studies, our study suggests that antipsychotics have a subtle but measurable influence on brain tissue loss over time, suggesting the importance of careful risk-benefit review of dosage and duration of treatment as well as their off-label use.

Anterior cingulate cortex: An MRI-based parcellation method

OBJECTIVE

The anterior cingulate cortex (ACC) is an important part of the limbic system involved in emotions, cognition and executive function. The ACC has structurally distinct subregions, both microscopically and functionally, that have been implicated in several major psychiatric disorders. However, a structural analysis of these subregions with magnetic resonance imaging (MRI) has not been done. Our main purpose was to develop an MRI-based parcellation method of the ACC that permits us to explore plausible abnormalities in 4 functionally relevant subregions: dorsal, rostral, subcallosal and subgenual.

METHODS

The reliability study for gray matter volume and surface area of each subregion was performed on 14 randomly selected MR scans by 3 different raters. Our method posits to conserve the topographic uniqueness of individual brains and is based on our ability to visualize both the 3-dimensional rendered brain and the 3 orthogonal planes simultaneously with BRAINS2 software. We developed rules to hand-trace regions of interest (ROI) to surround contiguous areas of gray matter for dorsal, rostral, subcallosal and subgenual regions. The ACC was then parcellated into these 4 distinct subregions (8 when both right and left hemispheres were measured).

RESULTS AND DISCUSSION

The intraclass R coefficients for gray matter volume of each subregion ranged between 0.85 and 0.93. The current study describes a new highly reliable and reproducible topography-based parcellation method of the ACC into its dorsal, rostral, subcallosal and subgenual regions.

CONCLUSIONS

This new parcellation method provides a new means of exploring the role of the functionally and structurally distinct subregions of the ACC in schizophrenia, depression and various other brain illnesses.

Manual and automated measurement of the whole thalamus and mediodorsal nucleus using magnetic resonance imaging

The thalamus is an important relay structure in the brain that may be relevant to a variety of brain diseases. It is divided into multiple subnuclei with different cortical connections. The medial dorsal (MD) nucleus is particularly important because it forms key connections with the prefrontal cortex. The current study reports precise and efficient methods for measuring the whole thalamus and the MD with MRI that have a high degree of interrater reliability. A multispectral image acquisition and novel image processing technique were used to improve structure visibility. The tricolor image assigns a color to each of the T1, T2, and PD weighted images, represented by red, green, and blue, respectively. The manually defined regions were then used to train an artificial neural network (ANN) to automatically define both the whole thalamus and the MD. The ANN provides an efficient automated method, making studies using larger sample sizes more feasible.

The Iowa Longitudinal Study of Recent Onset Psychosis: one-year follow-up of first episode patients

The natural history of schizophrenia remains unclear. One strategy to further inform this area is to prospectively evaluate individuals early in the course of the disorder, both in terms of symptomatic and psychosocial/occupational functioning. Subjects were recruited into the study if they were in the midst of their first psychiatric hospitalization for a non-'organic' psychotic disorder. Subjects were extensively evaluated at index with semi-structured interviews including the Comprehensive Assessment of Symptoms and History (CASH), and followed at 6-month intervals. Data are presented on 35 subjects who were followed through 1 year. There was a significant improvement in overall symptomatology during index hospitalization, but this was accounted for primarily by improvement of positive symptoms, with negative symptoms remaining prominent. No further improvement was noted between discharge and 1-year follow-up in any of the symptom measures. Employment, interpersonal relationships, and sexual activity remained markedly impaired throughout the follow-up period. These data demonstrate that; (1) negative symptoms are prominent and stable early in the course of the disorder; (2) symptom severity at discharge from index hospitalization is predictive of symptom severity at 1 year; and (3) despite substantial overall symptomatic improvement during the first hospitalization, psychosocial and occupational functioning were found to be markedly impaired at 1-year follow-up.

Withdrawal-emergent dyskinesia in patients with schizophrenia during antipsychotic discontinuation

We examined whether patients exhibiting withdrawal-emergent dyskinesia (WE-D) represent a group vulnerable to subsequent development of tardive dyskinesia (TD). WE-D was defined as moderate abnormal movements during antipsychotic withdrawal in persons without persistent TD. We assessed patients with schizophrenia-spectrum illness participating in withdrawal from antipsychotic medication. Patients with WE-D were compared to those without dyskinesia and to those with persistent TD. Clinical measures included duration of illness and antipsychotic exposure, negative symptoms, and neurologic soft signs. We hypothesized that WE-D patients would not differ from persistent-TD patients across the above variables, but would differ from non-TD patients. Patients without TD significantly differed from persistent TD in duration of illness, medication exposure and neurologic soft signs. WE-D did not differ from TD across these measures. No-TD patients also showed less duration of medication exposure and neurologic soft signs than those with WE-D.

Magnetic resonance imaging of the brain in schizophrenia. The pathophysiologic significance of structural abnormalities

In a second large series of schizophrenic patients studied with magnetic resonance imaging at the University of Iowa, Iowa City, earlier findings of decreased frontal, cerebral, and cranial size were not replicated. In this second series, control subjects were selected to be educationally equivalent to the schizophrenic patients, a modification in design that may partially account for the failure to replicate. By means of coronal images, ventricular volume was compared in patients and controls and found to differ to a highly significant degree, with the frontal horns being possibly slightly more enlarged than the rest of the ventricular system. A prominent sex effect was also observed, with most of the increased ventricular size occurring in the male patients. Within the male patients, the thalamus was also observed to be significantly smaller, a finding that could be consistent with periventricular injury. Patients with prominent negative symptoms had significantly larger ventricular size than did those with the mixed or positive subtypes. Because of its superior resolution, magnetic resonance imaging appears to offer a more sensitive index of ventricular enlargement than that provided by computed tomography.