Age at puberty and mental illness. Towards a neurodevelopmental aetiology of Kraepelin's endogenous psychoses

Adolescent Neurodevelopment and Vulnerability to Psychosis

Adolescence is characterized by significant changes in several domains, including brain structure and function, puberty, and social and environmental factors. Some of these changes serve to increase the likelihood of psychosis onset during this period, while others may buffer this risk. This review characterizes our current knowledge regarding the unique aspects of adolescence that may serve as risk factors for schizophrenia spectrum disorders. In addition, we provide potential future directions for research into adolescent-specific developmental mechanisms that impart vulnerability to psychosis and the possibility of interventions that capitalize on adolescents' unique characteristics. Specifically, we explore the ways in which gray and white matter develop throughout adolescence in typically developing youth as well as in those with psychosis spectrum disorders. We also discuss current views on the function that social support and demands, as well as role expectations, play in risk for psychosis. We further highlight the importance of considering biological factors such as puberty and hormonal changes as areas of unique vulnerability for adolescents. Finally, we discuss cannabis use as a factor that may have a unique impact during adolescent neurodevelopment, and subsequently potentially impact psychosis onset. Throughout, we include discussion of resilience factors that may provide unique opportunities for intervention during this dynamic life stage.

Rethinking schizophrenia through the lens of evolution: shedding light on the enigma

Schizophrenia refers to a complex psychiatric illness characterized by the heterogenic presence of positive, negative and cognitive symptoms occurring in all human societies. The fact that the disorder lacks a unifying neuropathology, presents a decreased fecundity of the affected individuals and has a cross-culturally stable incidence rate, makes it necessary for an evolutionary explanation that fully accounts for the preservation of “schizophrenic genes” in the global human genepool, explaining the potential sex differences and the heterogeneous cognitive symptomatology of the disorder and is consistent with the neuropsychological, developmental and evolutionary findings regarding the human brain. Here we proposed a new evolutionary framework for schizophrenia that is consistent with findings presented in different dimensions, considering the disorder as a form of brain functioning that allows us to adapt to the environment and, ultimately, maintain the survival of the species. We focus on the epigenetic regulation of thalamic interneurons as a major player involved in the development of the clinical picture characteristic of schizophrenia.

Contribution of sex hormones to gender differences in schizophrenia: A review

Female patients with schizophrenia tend to have a more benign course and better outcomes than males. One proposed explanation is the differential influence of male and female sex hormones, including estrogen, progesterone, testosterone, and dehydroepiandrosterone (DHEA) and its sulfate (DHEAS). Such benefit may be mediated by their effects on neurotransmitters and neuroprotection. Besides altered estrogen and DHEA/DHEAS levels in female patients, data is equivocal on hormonal differences between patients and controls. However, several reports note a mostly negative correlation between estrogen levels and symptom severity in both genders, and a positive correlation between estrogen levels and neurocognition but mainly in females. Adjunctive estrogen appears to improve symptoms in both genders. Progesterone levels have inconsistent links to symptom severity in both genders, and correlate positively with neurocognition but only in males. Estrogen-progesterone combination shows preliminary benefits as augmentation for both symptoms and neurocognition in females. Testosterone levels correlate inversely with negative symptoms in males and have inconsistent associations with neurocognition in both genders. Testosterone augmentation reduced negative symptoms in male patients in a pilot investigation, but has not been evaluated for neurocognition in either gender. DHEA/DHEAS have mixed results for their association with, and clinical utility for, symptoms and neurocognition in both genders. Overall, data on the impact of sex hormones on clinical course or as treatment for schizophrenia is limited, but estrogen has most evidence for positive influence and clinical benefit. The possibly greater tolerability and broader impact of these hormones versus existing medications support further exploration of their use.

Can age at sexual maturity act as a predictive biomarker for prodromal negative symptoms?

BACKGROUND

Puberty and reproductive hormones have been identified as having a potential role in schizophrenia. Earlier reports have suggested associations between later age at puberty and schizophrenia in males. Similarly, associations have been reported between testosterone levels and psychotic symptoms. In this report, we examined the association between age at puberty and prodromal symptoms of psychosis.

METHODS

58 child or adolescent family members of individuals with schizophrenia were interviewed using the Scale of Prodromal Symptoms and the Tanner Maturational Scale. Age at Tanner pubertal stage was determined and regression analyses were used to explore associations between prodromal symptoms and age at puberty.

RESULTS

Among males, delayed age at puberty was associated with greater severity of prodromal symptoms; the association between negative prodromal symptoms and delayed age was significant (p=0.001). In females, the association was not statistically significant.

CONCLUSIONS

Our results suggest that delayed age at puberty may be associated with negative prodromal symptoms of schizophrenia in males. Our findings suggest that delayed age at puberty could potentially be a predictive biomarker for psychopathology in males at risk for schizophrenia.

Kraepelin's dichotomy is true: contrasting brain dysfunction at the extremes of human growth and maturation. Excitability, the fundamental property of nervous tissue, is affected

The distribution of Kraepelin's ubiquitous dichotomy varies with standard of living and pubertal age: when one rises, the other declines. The universal similar clinical picture--mortality risk, manic depressive psychosis, episodic dysfunction of brainstem control systems (sleep-wake cycle, food, mood control mechanism)--is caused by abridged pubertal pruning of excitatory synapses, which is treated with anti-epileptics, as opposed to convulsant neuroleptics in dementia praecox, where the clinical variation reflects varying degrees of excessive pruning and deficit in excitability. Localization of cortical breakdown of circuitry, silent spots and persistent dysfunction due to insufficient fill-in mechanisms, determine the clinical picture. This ranges from dementia praecox in late puberty and poor living standards, to cognitive dysfunction (mainly with higher standards of living) with earlier puberty. This variation is the most likely explanation why the acceptance of dementia praecox as a disease entity was complicated. Kraepelin's dichotomy, episodic dysfunction against a clinical deterioration, is at the extremes of brain maturation; the fundamental property of nervous tissue, excitability, is affected. To reduce the risk of psychotic episodes, omega-3 might also be given, as it normalizes excitation at all levels. The neo-Kraepelinian atheoretical quantitative scoring systems have eliminated disease entities and neglected endogeneity in psychiatry. We are back to a pre-Kraepelinian state, without his systematic observations. What is psychiatry without Kraepelin's dichotomy? Mood stability is a fundamental personality trait with a normal distribution; what is considered within or outside normal variation is arbitrary. Given the mood-stabilizing effect of anti-epileptics and omega-3, these will increasingly dominate psychiatric treatment.

What is a psychosis and where is it located?

Kraepelin's dichotomy, manic-depressive insanity and dementia praecox, are contrasting and true endogenous disease entities which affect excitability, the fundamental property of the CNS. Kraepelin wanted to establish a valid classification and hit the extremes in brain structure and function at a time when we had no knowledge of brain dysfunction in "functional" psychoses. The aetiology is now known: the psychoses are part of human growth and maturation and might be classified according to their brain dysfunction, which is exactly what Kraepelin wanted. However, presumably to reduce the stigma attached to the word "psychosis", there is currently a strong initiative to eliminate the concept. But knowledge of what is happening in the brain in a psychosis might be more helpful in reducing stigma. It is suggested that psychosis is due to an affection of the supplementary motor area (SMA), located at the centre of the Medial Frontal Lobe network. The SMA is one of the rare universally connected areas of the brain, as should be the case for such a key structure that makes decisions as to the right moment for action. This important network, which partly has continuous neurogenesis, has sufficiently widespread connections. The SMA, a premotor area located on the medial side of the frontal lobes, is one of the last regions to reach a concurrence of synaptogenesis. An affection of the SMA, a deficient or abolished Delayed Response Task, seriously disturbs our relation and adaptation to the surroundings. We usually master the Delayed Response Task around the age of 7 months, a time at which the second CNS regressive event takes place, which proceeds from the posterior to the anterior of the brain. In very late maturation, a persistent affection of the SMA might occur. We experience a chronic psychosis: infantile autism (IA), a chronic inability to act consciously, which contrasts with the episodic SMA affection post-puberty, when excitation is reduced due to excessive pruning of excitatory synapses. Silent spots are the result of insufficient fill-in mechanisms following a breakdown of circuitry. They may affect the SMA in the case of very late puberty. An acute reduction in excitation and concomitantly a marked increase in silent spots might lead to an acute psychosis. A frontal preference is likely, given that a reduction might occur anywhere in the cortex, but particularly in the areas maturing latest. The varying localisations probably explain the difficulty in accepting schizophrenia as a disease entity. The multifactorial inheritance of the dichotomy implies that the genetics are not fate, a psychotic development might be prevented given enough epigenetic factors: brain food (omega 3). Might the present dietary adversity, with its lack of brain food, be responsible for a rising incidence in psychosis? A psychosis is an understandable and preventable dysfunction of the brain, and its mechanisms are known. Primarily a disorder of reduced excitation in an attenuated CNS, this explains why all the neuroleptics are convulsants, raising excitation, in contrast to all antidepressives, which are anti-epileptic.

Public health implications of altered puberty timing

Changes in puberty timing have implications for the treatment of individual children, for the risk of later adult disease, and for chemical testing and risk assessment for the population. Children with early puberty are at a risk for accelerated skeletal maturation and short adult height, early sexual debut, potential sexual abuse, and psychosocial difficulties. Altered puberty timing is also of concern for the development of reproductive tract cancers later in life. For example, an early age of menarche is a risk factor for breast cancer. A low age at male puberty is associated with an increased risk for testicular cancer according to several, but not all, epidemiologic studies. Girls and, possibly, boys who exhibit premature adrenarche are at a higher risk for developing features of metabolic syndrome, including obesity, type 2 diabetes, and cardiovascular disease later in adulthood. Altered timing of puberty also has implications for behavioral disorders. For example, an early maturation is associated with a greater incidence of conduct and behavior disorders during adolescence. Finally, altered puberty timing is considered an adverse effect in reproductive toxicity risk assessment for chemicals. Recent US legislation has mandated improved chemical testing approaches for protecting children's health and screening for endocrine-disrupting agents, which has led to changes in the US Environmental Protection Agency's risk assessment and toxicity testing guidelines to include puberty-related assessments and to the validation of pubertal male and female rat assays for endocrine screening.

Infantile autism: a chronic psychosis since infancy due to synaptic pruning of the supplementary motor area

The rise in Infantile Autism, learning problems, cognitive decline with age, Alzheimer's, Parkinson's Diseases and the SIDS epidemic, has a common cause in the rising dietary deficit in Omega-3 brain-food. This paper suggests that aside from the wider concept of Autism Spectrum Disorders (ASD) and Pervasive Developmental Disorders (PDD), the rise in Infantile Autism (IA) in the last decade is the effect of deficient brain-food (Omega-3). The consequent delay of development prolongs the 2nd regressive event in infancy to pruning of the centre in the Medial Frontal Lobe System that connects Hippocampus and Cingulum. With a consequently defective Supplementary Motor Area (SMA), the Delayed Response Function is affected leading to persistent psychosis. Post-Pubertal Episodic Psychoses are associated with acute reduction of excitation, a risk of breakdown of circuitry, insufficient fill-in mechanisms, and silent spots. An acute psychosis occurs if the silent spots comprise of SMA. Only two brain areas have continuous neurogenesis, indicating their important functions: the Hippocampus and Olfactory Bulb that belongs to the Lateral Frontal Lobe System essential to survival. Concerned with necessity of action in response to the environment, it relies upon short-term memory and Acute Feedback Mechanisms influenced by emotion and motivation from the external world. In contrast, the Medial Frontal Lobe network is controlled by Feed-Forward Predictive Mechanisms related to storage of information. The Delayed Response Function is mastered at 7 months, when 2nd event occurs with pruning of axons and dendrites. An abolished or defective Delayed Response Function seriously incapacitates an individual: A defective "Social Brain" with an inability for conscious action and to communicate, predominates in IA. There is a near lack of speech, despite normal vision and hearing in the minority without marked adversity in pregnancy, at delivery or in infancy. I propose that the recent rise in IA despite no rise in adversity signifies a rising deficiency in brain-food. That this is so is suggested by a changing clinical picture: no Mental Retardation in an IA majority. Deficit in Olfaction is pathognomonic in schizophrenia since 30 yrs and distinguishes the Asperger Syndrome. If brain-food deficiency alone sufficiently prolongs pruning to cause absent activity in SMA in infancy, less mentally retarded IA from other causes might be observed. Deficit in brain-food was evident in the Sudden Infant Death Syndrome: birthweight averaged 200-300 g lower than sibs, Omega-3 levels in brainstem were lower than controls. Only 20 % SIDS died in first hypoxic episode, suggesting such episodes are more frequent than we imagined. Children with learning-behaviour problems have similarly depressed birthweight. A general deficiency in Omega-3 contributes to the lacking reduction in Schizophrenia, despite early puberty predominates. Olfactory Bulb is first affected in the Alzheimer's and Parkinson's Disease. Cognitive decline with age, Hippocampal dysfunctions rise markedly irrespective of disease, but the major mental illnesses and Infantile Autism in particular, benefit from "brain-food" that might also prevent a development of these disorders. To secure optimal brain function in the coming generations, there is a need to change the diet now from its emphasis on protein for body growth to food for the brain. This means there is a need to increase fish and sea food consumption.

Are neurodegenerative disorder and psychotic manifestations avoidable brain dysfunctions with adequate dietary omega-3?

The present mismatch between what our brain needs, and the modern diet neglects our marine heritage. Last century, the priority in nutrition and food production was to achieve a high protein diet and somatic growth and function. The dietary content of omega-3 (N-3) required by the brain was neglected although evidence for the essentiality of certain fatty acids was published in 1929 and specifically re-affirmed for omega 3 in the brain in the 1970s. Cognitive decline with age and neurodegenerative disorder with dementia are now rising. This review describes signs of N-3 deficit in Alzheimer and Parkinson Disease, where maximum change involves the primary sites: olfactory cortex and the hippocampus. The olfactory agnosia observed in schizophrenia supports an N-3 deficit as does a reduction of key ologodendrocyte- and myelin-related genes in this disorder and affective disorder, where a rise in dementia accords with a deficit of N-3 also in this disorder. N-3 normalizes cerebral excitability at all levels. That the two disorders are localized at the extremes of excitability, is supported by their opposing treatments: convulsant neuroleptics and anti-epileptic antidepressants. An adequate N-3 diet will probably prevent most psychotic episodes and prove that neurodegenerative disorder with dementia is also to a large extent not only preventable but avoidable.

From genetics to epigenetics

In the post human-genome area, the challenge is to derive details of heritable variation in relation to how human variation reflects adaptation to the different environments. Heterozygote advantage represents a superior genetic adaptation presumably explaining the presence of the allele at frequencies above those to be expected from a simple replacement of a homozygous lethal allele by mutation alone (Saugstad 1977a, 1975b, 1972). Mean birthweight of unaffected offspring of parents heterozygous for the phenylketonuria (PKU) allele averaged significantly above mean weight of all Norwegian births, rendering unaffected offspring more viable at birth and thus improving the chance for survival of the allele. A successful adaptation requires natural selection acting on that part of the body that makes a difference in survival. Skin colour variation is such a successful adaptation, for the North as opposed to the dark skins of the equator. Human Evolution in Africa and subsequent adaptations have enabled human survival all over the world with highly different light intensity (Jablonski & Chaplin 2000). That continuous variables, height, pubertal age and brain development, are multifactorially inherited and affected by epigenetic factors, was nicely demonstrated in the increase in height in Norway 1860-1960 with at the same time a reduction in pubertal age by 4yrs which may have affected the final stage in brain development. This created an increased need for brain food, N-3, to secure optimal brain function. Body growth is not brain growth. Given that the consumption of brain food (N-3) has declined to 20% only of the level 100yrs ago, what disorders are to be expected with an N-3 dietary deficit: in pregnancy, infancy and later in life? In this paper I discuss the significance of prepubertal selective pruning of excitatory synapses compared to delayed pruning and suggest relationships with brain disorders.

Are neurodegenerative disorder and psychotic manifestations avoidable brain dysfunctions with adequate dietary omega-3?

The present mismatch between what our brain needs, and the modern diet neglects our marine heritage. Last century, the priority in nutrition and food production was to achieve a high protein diet and somatic growth and function. The dietary content of omega-3 (N-3) required by the brain was neglected although evidence for the essentiality of certain fatty acids was published in 1929 and specifically re-affirmed for omega 3 in the brain in the 1970s. Cognitive decline with age and neurodegenerative disorder with dementia are now rising. This review describes signs of N-3 deficit in Alzheimer and Parkinson Disease, where maximum change involves the primary sites: olfactory cortex and the hippocampus. The olfactory agnosia observed in schizophrenia supports an N-3 deficit as does a reduction of key ologodendrocyte- and myelin-related genes in this disorder and affective disorder, where a rise in dementia accords with a deficit of N-3 also in this disorder. N-3 normalizes cerebral excitability at all levels. That the two disorders are localized at the extremes of excitability, is supported by their opposing treatments: convulsant neuroleptics and anti-epileptic anti-depressants. An adequate N-3 diet will probably prevent most psychotic episodes and prove that neurodegenerative disorder with dementia is also to a large extent not only preventable but avoidable.

From superior adaptation and function to brain dysfunction--the neglect of epigenetic factors

With optimal pregnancy conditions (natural, enriched diet which includes fish) African (Digo) infants are 3-4 weeks ahead of European/American infants in sensorimotor terms at birth, and during the first year. Infants of semi-aquatic sea-gypsies swim before they walk, and have superior visual acuity compared with us. With adverse pregnancy behaviour (fear of fat, a trend to dieting), neglecting the need for brain fat to secure normal brain development and function, we run a risk of dysfunction--death. Sudden Infant Death Syndrome victims have depressed birth weight, lower levels of marine fat in brainstem than controls, and >80 suffer multiple hypoxic episodes prior to death. Depressed birth weight (more than 10% below mean) is seen in learning and behaviour disorders, and a trend towards weights of less than 3kg is increasing, which supports a rise in antenatal sub optimality. Given marine fat deficiency in pregnancy and infancy, neurons starved for fuel could delay myelination and maturation in the latest developed Frontal Lobes. The phylogenetic oldest Lateral Frontal Lobe System (feed-back mechanism etc.) derived from olfactory bulb-amygdala, which crosses in Anterior Commisure is probably spared, while the Medial Frontal Lobe System derived from Hippocampus-Cingulum and crosses in Corpus Callosum (delayed response task) is most likely affected. The rise in infantile autism (intact vision and hearing) with deficit in delayed response task only, could suggest a deficit in the Medial Frontal Lobe System. The human species is unique; 70% of total energy to the foetus goes to development of the brain, which mainly consists of marine fat. It undergoes pervasive regressive events, before birth, in infancy and at puberty. Minimal retraction of neuronal arborisation is advantageous. Attributable to adverse pregnancy childrearing practice, excessive retraction is likely prenatally and in infancy. Pubertal age affects the fundamental property of nervous tissue, excitability: excessive excitatory drive is seen in early, and a deficiency in late puberty. It is postulated that with adequate marine fat, there is probably no risk of psychopathology at the extremes, whereas a deficiency could lead to paroxysmal (subcortical) dysfunction in early puberty, and breakdown of cortical circuitry and cognitive dysfunctions in late puberty. The post-pubertal psychoses, schizophrenia and manic-depressive psychosis at the extremes of the pubertal age continuum, with contrasting excitability and biological treatment, are probably the result of continuous dietary deficiency, which has inactivated the expression of genes for myelin development and oligodendrocyte-related genes in their production of myelin. The beneficial effect of marine fat in both disorders, in other CNS disorders as well as in developmental dyslexia (DD) and ADHD among others, supports our usual diet is persistently deficient. We have neglected the similarity of our great brain to other mammals, and our marine heritage. Given the amount of marine fat needed to secure normal brain development and function is not known, nor the present dietary level, it seems unduly conjectural to postulate that a dietary deficiency in marine fat is causing brain dysfunction and death. However, all observations point in the same direction: our diet focusing on protein mainly, is deficient, the deficiency is most pronounced in maternal nutrition and in infancy.

Schizophrenia—an evolutionary enigma?

The term 'schizophrenia' refers to a group of disorders that have been described in every human culture. Two apparently well established findings have corroborated the need for an evolutionary explanation of these disorders: (1) cross-culturally stable incidence rates and (2) decreased fecundity of the affected individuals. The rationale behind this relates to the evolutionary paradox that susceptibility genes for schizophrenia are obviously preserved in the human genepool, despite fundamental reproductive disadvantages associated with the disorders. Some researchers have therefore proposed that a compensatory advantage must exist in people who are carriers of these genes or in their first-degree relatives. Such advantages were hypothesised to be outside the brain (e.g. greater resistance against toxins or infectious diseases), or within the social domain (e.g. schizotypal shamans, creativity). More specifically, T.J. Crow has suggested an evolutionary theory of schizophrenia that relates the disorders to an extreme of variation of hemispheric specialisation and the evolution of language due to a single gene mutation located on homologous regions of the sex chromosomes. None of the evolutionary scenarios does, however, fully account for the diversity of the symptomatology, nor does any one hypothesis acknowledge the objection that the mere prevalence of a disorder must not be confused with adaptation. In the present article, I therefore discuss the evolutionary hypotheses of schizophrenia, arguing that a symptom-based approach to psychotic disorders in evolutionary perspective may improve upon the existing models of schizophrenia.

Neural stability and flexibility: a computational approach

This paper addresses the issue of stability and flexibility of neural systems, and how a balance can be achieved. Assuming a close correspondence with cognitive and mental processes, we use a cortical neural network model to investigate how regulation of the neurodynamics can result in an efficient information processing, in terms of learning and associative memory. In particular, we use this model to investigate relations between structure, dynamics, and function of a neural system, and how the stability-flexibility dilemma may be solved by proper regulation. We focus on the complex neurodynamics and its modulation, and how this is related to the neural circuitry, where synaptic modification and network pruning are considered. Finally, we discuss the relevance of these results to clinical and experimental neuroscience and speculate on a link between neural instability and mental disorders.

Quantitative Signal Intensity Measures on Magnetic Resonance Imaging in Attention-Deficit Hyperactivity Disorder

OBJECTIVE

The aim of this study was to investigate possible abnormalities of cerebral myelination in subjects with attention-deficit hyperactivity disorder (ADHD).

BACKGROUND

Anatomic and functional neuroimaging studies of subjects with ADHD demonstrated a right frontostriatal deficit and abnormal cerebral asymmetries. Some also reported white matter abnormalities, such as smaller white matter volumes in the right anterior-superior frontal region, and the smaller bilateral retrocallosal region. Smaller volumes in specific areas of the corpus callosum have also been reported. We hypothesized that white matter signal intensities may also show differences indicating abnormal cerebral myelination.

METHOD

We analyzed T2-weighted magnetic resonance images of 11 adolescents with ADHD and 20 controls. Regions of interest were set in both the white and gray matter in frontal and parieto-occipital associative regions.

RESULTS

The ADHD group showed a higher signal intensity ratio, probably reflecting a higher degree of myelination. Significant interhemispheric differences emerged only in the posterior region in the ADHD group.

CONCLUSIONS

The higher degree of myelination in the right frontal region of ADHD may be due to a compensatory mechanism for the right frontostriatal dysfunction.

Our neglect of the normal variation is linked to a reluctance to accept multifactorial inheritance and the role of environment

One of the most surprising evolutionary discoveries is that wild species similar to human contain a vast reservoir of variability. Why are we persistently reluctant to discuss normal variation in brain structure and function and label any deviation pathological? Despite the failure of Mendelian Genetics to solve the genetic puzzle in psychiatry, we refuse to discuss multifactorial inheritance and the role of environmental factors. Rising living conditions (high protein diet) accelerate maturation, lower pubertal age, shift body-built toward more weight for height and cerebral excitability toward higher levels. Another environmental factor which has to be provided by diet is marine fat which our brain consists of. It normalizes brain function at all levels of excitability and possibly prevents psychotic episodes if adequately supplied. As part of Human Variation in Growth and Maturation, Schizophrenia and Manic-depressive psychosis are multifactorially inherited and share susceptibility loci. They are localized at the extremes of variation. Excitability, body-built, clinical picture and CNS finding accord with this, their phenotypic characteristics might prove valuable in a hunt for genes not common to both disorders.

Pubertal neurodevelopment and the emergence of psychotic symptoms

One of the chief epidemiological hallmarks of schizophrenia is its modal age at onset in early adulthood. Clinical onset is preceded by an adolescent period that is usually characterized by increasing adjustment problems. Recent theorizing about the etiology of schizophrenia has focused on postpubertal brain changes that may be involved in triggering the expression of vulnerability for schizophrenia. In this paper, we further examine the normal neurodevelopmental processes that occur in adolescence and the underlying role of hormonal factors in controlling the expression of genes that govern brain maturation. We then consider how postpubertal hormone changes might serve to trigger the expression of vulnerability genes that code for abnormal brain development.

Manic depressive psychosis and schizophrenia are neurological disorders at the extremes of CNS maturation and nutritional disorders associated with a deficit in marine fat

The maturational theory of brain development comprises manic depressive psychosis and schizophrenia. It holds that the disorders are part of human diversity in growth and maturation, which explains their ubiquity, shared susceptibility genes and multifactorial inheritance. Rate of maturation and age at puberty are the genotype; the disorders are localized at the extremes with normality in between. This is based on the association between onset of puberty and the final regressive event, with pruning of 40% of excitatory synapses leaving the inhibitory ones fairly unchanged. This makes excitability, a fundamental property of nervous tissue, a distinguishing factor: the earlier puberty, the greater excitability--the later puberty, the greater deficit. Biological treatment supports deviation from the norm: neuroleptics are convulsant; antidepressives are anti-epiletogenic. There is an association between onset of puberty and body-build: early maturers are pyknic broad-built, late ones linearly leptosomic. This discrepancy is similar to that in the two disorders, supporting the theory that body-build is the phenotype. Standard of living is the environmental factor, which affects pubertal age and shifts the panorama of mental illness accordingly. Unnatural death has increased with antipsychotics. Other treatment is needed. PUFA deficit has been observed in RBC in both disorders and striking improvements with addition of minor amounts of PUFA. This supports that dietary deficit might cause psychotic development and that prevention is possible. Other neurological disorders also profit from PUFA, underlining a general deficit in the diet.

Relationship between sex differences in onset of schizophrenia and puberty

Some neurodevelopmental hypotheses of schizophrenia have postulated that sex differences in onset of illness could be explained by sexual dimorphism in onset of puberty, suggesting that early maturation accounts for the later onset of illness in women. The objective of this study was to analyse the relationship between age of menarche and age of onset of schizophrenia in a sample of Chilean patients. The medical records of 105 schizophrenic women diagnosed according to DSM-III-R criteria were studied. In all cases age of onset (first psychotic symptoms) and age of menarche were obtained. Pearson's correlation and student's t-test were used to analyse the data. The mean age of menarche in the sample of female patients (12. 98 years, S.D.=1.49) was significantly different from that of the general population of Santiago, Chile (12.53 years, S.D.=1.32) (t=2. 38; P<0.05). The mean age of onset of schizophrenia in female patients (19.92 years, S.D.=5.13) was significantly earlier in the Chilean sample than that reported in European and North American samples (P<0.05). No differences were observed when comparing the mean age at menarche. The subtypes with the earliest onset presented the earliest age of menarche and the subtypes with the latest onsets showed the latest ages at menarche. However, no correlation was observed between the age at onset of illness and the age at menarche, both in the total sample and in the analysis by subtype. The results of this study do not support a correlation between puberty and age of onset of illness.

A lack of cerebral lateralization in schizophrenia is within the normal variation in brain maturation but indicates late, slow maturation

The planum temporale (PT) bias, PT leftward, PT symmetry, and PT rightward reversal and sidedness preference, consistent right-handedness, ambilaterality, and consistent left-handedness are placed on a continuum mirroring the normal variation in rate of brain maturation. Maturational rate declines as we pass from PT leftward bias and consistent right-handedness to PT reversal and consistent left-handedness. Concomitantly, we expect an increased prevalence of males due to their pubertal age being about 2 years later than that of females, and a shift in cognitive profile from higher verbal scores than performance scores on the WAIS to higher performance than verbal scores. Three disorders fulfilling the criteria of late CNS maturation apart from the corresponding cognitive profile were studied: infantile autism (IA), schizophrenia (S), and developmental dyslexia (DD). These disorders have in common deficits in cognition, perception, and somatomotor function. The deficits range from an arrest in brain development (which is evident in infancy superimposed on late maturation in IA) to overall delayed brain and somatic development in S (culminating in postpubertal psychotic episodes and persistent and generalized residual deficits). Finally, reading inability, problems in perception (vision and hearing) and in motor coordination, particularly between the two hemispheres, characterize DD. Enhancing brain maturation and the prevalence of 'normal' cerebral asymmetry--laterality is preferable if we want to reduce the risk of developing the above-mentioned disorders. It is suggested that in the past environmental challenges have favored early maturation, with its abundant neuronal population, arborization and excessive density of synapses and cerebral excitability which has powered evolution through the mechanism of natural selection. Early maturation is obtainable through optimal nutrition, including a satisfactory amount of marine fat (PUFA), before and during pregnancy and later in life.

Cerebral lateralisation and rate of maturation

Multifactorial inheritance applied to brain development implies a large continuum of normal variation with deviation from the norm at the extremes of maturational rate. The greater population of neurons, greater arborization of neural networks and excessive synaptic density in early maturation imply that adaptability (plasticity) is a main advantage, as opposed to a deficit in adaptability associated with the reduced number of neurons, reduced connectivity and reduced synaptic density in late slow maturation. It is hypothesised that Planum Temporale (PT) asymmetry and hand-preference predict the rate of CNS maturation as does the cognitive profile on the Wechsler Adult Intelligence Scale (WAIS): PT leftward asymmetry, right-handedness and a left-hemisphere cognitive advantage signifies early fast maturation: PT rightward asymmetry, left-handedness and a right-hemisphere cognitive advantage signify late maturation, while PT symmetry and ambilaterality represent rates of maturation in between. The slower development of males implies a male predominance in disorders affecting late maturers: Developmental Dyslexia (DD) with a predominance of rightward PT asymmetry/symmetry, left-handedness and multiple functional deficits, as well as excessive regressive events confirmed on PT/MRI. Schizophrenia, hypothesised to be a disorder in late maturers, is distinguished by rightward asymmetry/symmetry. Left-handedness and DD are common as is prior delayed development supporting excessive regressive events as do the findings on PT/MRI. To reduce the risk of DD and schizophrenia requires a reduction in late maturation through the enhancement of maturational rate by optimal nutrition before and during pregnancy and later.

Childhood precursors of psychosis as clues to its evolutionary origins

Those who as adults will be admitted to a psychiatric ward with a psychotic illness can be distinguished (on the basis of group differences) from others by their behaviour and academic performance at the ages of 7 and 11 years. Pre-schizophrenic boys are anxious and hostile towards adults and peers at the age of 7 years and show poor concentration. By age 11 years these boys are also rated as depressed, and pre-schizophrenic girls as depressed and withdrawn. Pre-affective psychotic boys show minor changes (for example an increase in hostility and restlessness) at age 7 years, although these features are not obvious at age 11 years. Abnormalities that in some respects resemble those in pre-schizophrenic boys are present at age 11 years in a group of females who will be admitted to psychiatric units with non-psychotic diagnoses by the age of 28 years. Academic impairments (including speech and reading difficulties) at ages 7, 11 and 16 years are more severe in pre-schizophrenics than in the other groups. Schizophrenics-to-be are slow to develop continence and show poor coordination and vision at age 7 years, and are rated clumsy at age 16 years. Psychosis reflects a disturbance of aspects of central nervous system function that are time-dependent and in certain respects gender specific. It is argued that the psychoses represent extremes of variation in a gene (or genes) that differs between sexes and controls the timing of development of the two cerebral hemispheres.(ABSTRACT TRUNCATED AT 250 WORDS)

Deviation in cerebral excitability: possible clinical implications

Schizophrenia, a chemical signaling disorder in the brain, is also a deteriorating neurological disorder. The deficit in cerebral excitability, and associated reduced synaptic density, imply a risk of cortical breakdown of circuitry accompanied by an insufficient fill-in mechanism, and persistent silent spots, but no total loss of function, only dysfunction. This is subjectively experienced as deficiencies of cognition, perception and sensorimotor phenomena depending upon localization and connections of the disconnected circuitry. Considering the adversity inherent in this neural network, both the fast Hebbian pre-post form of learning and the slow pre-modulatory coincidence form of learning are probably impaired. The use of Feed Back Loops which usually govern our behaviour might also be impaired. In addition, we have to consider the daily problem of insufficient drive and motivation. Manic depressive psychosis, a chemical signaling disorder in the brain, is a true functional psychosis. The raised excitatory drive and raised synaptic density imply raised risk of uncoupling of circadian rhythms via the direct glutamatergic input to the suprachiasmatic nucleus of hypothalamus (SCN). This episodic brain stem dysfunction illustrates how a deficit in inhibition renders the brain unstable. The requirements of the fast Hebbian form of learning should easily be met, and neither should the slow forms of learning present a problem in networks characterized by excessive density.(ABSTRACT TRUNCATED AT 250 WORDS)

The maturational theory of brain development and cerebral excitability in the multifactorially inherited manic-depressive psychosis and schizophrenia

An association has been established between the multifactorially inherited rate of physical maturation and the final step in brain development, when some 40% of synapses are eliminated. This may imply that similarly to endocrine disease entities, we have cerebral disease entities at the extremes of the maturational rate continuum. The restriction of prepubertal pruning to excitatory synapses leaving the number of inhibitory ones fairly constant, implies changes in cerebral excitability as a function of rate of maturation (age at puberty). In early maturation there will be an excess in excitatory drive due to prematurely abridged pruning, which compounds a synchronization tendency inherent in excessive synaptic density. Lowering excitatory level with antiepileptics is hypothesized to be a logical treatment in this type of brain dysfunction. In late maturation, a deficit in excitatory drive due to failure to shut down the pruning process associated with a tendency to the breakdown of circuitry and desynchronization, adds to a similar adversity inherent in reduced synaptic density. Raising the excitatory level with convulsants is hypothesized to be the treatment for this type of CNS dysfunction. The maturational theory of Kraepelin's psychoses holds that they are naturally occurring contrasting chemical signaling disorders in the brain at the extremes of the maturational rate continuum: manic depressive psychosis is a disorder of the early maturer and comprises raised cerebral excitability and a raised density of synapses. This is successfully treated with anti-epileptics like sodium valproate and carbamazepin. Schizophrenia is a disorder in late maturation with reduced cerebral excitability and reduced synaptic density. This is accordingly treated with convulsants such as typical and atypical neuroleptics. However, the conventional effective treatments in both disorders act on inhibition only by either lowering or raising inhibitory level. While the neuroleptics drugs are superior anti-psychotics they nevertheless do not affect the deviation in cerebral excitability which would explain why they do not cure. Disturbed circadian rhythms which precede psychotic episodes in manic depressives accord with a primary dysfunction in the CNS, the suprachiasmatic nucleus of the hypothalamus via its direct input the glutamatergic retinohypothalamic tract. The residual deficits in schizophrenia accord with persistently disconnected circuitry and communication which is a consequence of reduced excitatory level and is manifested in insufficient motivation, a reduced drive associated hypofunction, and neuromuscular dysfunction.

Is schizophrenia due to excessive synaptic pruning in the prefrontal cortex? The Feinberg hypothesis revisited

Several lines of evidence support the notion that a substantial reorganization of cortical connections, involving a programmed synaptic pruning, takes place during adolescence in humans. A review of neurobiological abnormalities in schizophrenia indicates that the neurobiological parameters that undergo peripubertal regressive changes may be abnormal in this disorder. An excessive pruning of the prefrontal corticocortical, and corticosubcortical synapses, perhaps involving the excitatory glutamatergic inputs to pyramidal neurons, may underlie schizophrenia. A reciprocal failure of pruning in certain subcortical structures, such as lenticular nuclei, may also occur. Several developmental trajectories, related to early brain insults as well as genetic factors affecting postnatal neurodevelopment, could lead to the illness. These models would have heuristic value and may be consistent with several known facts of the schizophrenic illness, such as its onset in adolescence and the gender differences in its onset and natural course. The relationship between these models and other etiological models of schizophrenia are summarized and approaches to test relevant hypotheses are discussed.

Higher morbidity risk for schizophrenia in males: fact or fiction?

Male to female ratios in published annual incidence rates for schizophrenia range from 0.70 to 3.47. These variations between studies are attributed to differences in sampling, diagnostic criteria, design characteristics, and methods of calculation, which limit the quality of the studies. In an effort to overcome these shortcomings, we collected a comprehensive sample of 392 consecutive first admissions with a diagnosis of schizophrenia or a similar disorder out of a population of 1.5 million in a central region of western Germany. In this large representative sample, no significant gender differences in the incidence of schizophrenia could be detected regardless of different diagnostic definitions.

An update of the zinc deficiency theory of schizophrenia. Identification of the sex determining system as the site of action of reproductive zinc deficiency

The following article updates the GZD theory of schizophrenia (1) by showing that male transmission of risk, the parental age effect, racial differences in birth seasonality, the disturbed sex ratios in the offspring of schizophrenic mothers and the association between diabetes and schizophrenia are explained by changes to zinc homeostasis. A genetic component to the disorder is now seen as unnecessary, transmission of risk by either parent, and twin concordance differences can be explained by other means. The primary site of action of GZD is identified as the putative ZFY sex determining system. Evidence suggesting that other mental disorders might be caused by GZD is also discussed.

Subtypes of schizophrenia--evidence from a twin-family study

In a combined twin-family study, the concordance for subtype of schizophrenia was investigated. The sample included 31 monozygotic (MZ) and 28 dizygotic (DZ) twin probands fulfilling the criteria of DSM-III-R schizophrenia. Their co-twins and first-degree relatives were personally interviewed and diagnosed in accordance with DSM-III-R. Any twin or relative diagnosed as schizophrenic was subclassified as either paranoid or nonparanoid. Schizophrenia was more often observed in co-twins of MZ probands with nonparanoid schizophrenia than in MZ probands with paranoid schizophrenia, indicating a stronger genetic influence in nonparanoid schizophrenia. Fifteen MZ pairs were concordant for schizophrenia, and 13 of these pairs were also concordant for subtype. Such a relationship was not observed in the first-degree relatives with schizophrenia. Our results indicate a complex etiology of subtypes in schizophrenia, and to some extent the etiology of subtypes may differ from the etiology of schizophrenia.

Dopamine and norepinephrine activity in schizophrenia. An integrative perspective

The dopamine (DA) hypothesis of schizophrenia stated that increased DA activity is the primary cause of schizophrenia. Recently, even though increased DA activity is in fact involved in psychotic symptoms and antipsychotic drug response, it has become clear that decreased DA activity is present in remitted and chronic states and may relate to deficit symptoms and cortical lesions. In addition, the norepinephrine (NE) system seems to be involved in symptomatology, antipsychotic drug response, course, and outcome in schizophrenia. This review supports the hypothesis that a disturbance in DA and NE activity regulates schizophrenic behavior. A plethora of DA- and NE-related findings in schizophrenic patients are reviewed in relationship to each other according to basic science data and to presently entertained hypotheses, with emphasis on a neural developmental disturbance interacting with a genetic predisposition shaped by environmental factors.

Neuropeptide Y-like immunoreactivity in schizophrenia. Relationships with clinical measures

Neuropeptide Y-like immunoreactivity (NPY-li) was measured in CSF of 35 drug-free chronic schizophrenic patients. Compared to a group of drug-free controls, CSF NPY-li was significantly higher in these patients. CSF NPY-li decreased with age and longer duration of illness. Measures of structural brain abnormalities on CT scans were significantly associated with lower CSF NPY-li. Relationships between NPY-li and schizophrenic behavior, i.e. positive symptoms, were observed only in the clinically stable (nonrelapsed) drug-free patients. In 31 of the patients CSF was obtained before and after withdrawal from haloperidol maintenance treatment. This withdrawal from haloperidol treatment was associated with a significant increase in CSF NPY-li. There was no significant difference in CSF NPY-li between patients who did and those who did not relapse within 6 weeks following haloperidol withdrawal. The present findings suggest a relationship of CSF NPY-li with various aspects of schizophrenia.