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Does Schizophrenia Skip A Generation

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Family History And The Nature Of Its Relationship To Schizophrenia

Lecture 27 Schizophrenia and First Generation Antipsychotic Medications

Family history in general is the number one predictor for schizophrenia, and by a wide margin. Among the general population the likelihood of any particular individual being diagnosed with schizophrenia is right around one percent, but that number rises by several percentage points when family members have also been diagnosed with the condition.

When one identical twin has been diagnosed with schizophrenia, the chances of the other twin also being diagnosed are 48 percent. This is the highest correlation based on specific family relationship here are the others:

  • First cousin, uncle, or aunt diagnosed: 2 percent
  • Nephew or niece diagnosed: 4 percent
  • Grandchild diagnosed: 5 percent
  • Half-brother or sister diagnosed: 6 percent
  • One parent diagnosed: 6 percent
  • Full sibling diagnosed: 9 percent
  • One or more children diagnosed: 13 percent
  • Fraternal twin diagnosed: 17 percent

What this list means is that for every schizophrenia sufferer in the general population, there will be six schizophrenia victims among those whose parents have the disorder, nine among those who have schizophrenic siblings, and so on.

Schizophrenia genetic risk factors are real, but they donât completely define or control the disorder. Environmental risk factors and the biological effects they cause are an important supplementary aspect in the causal chain that leads to schizophrenia.

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“Mental health disorders are not about a single gene but about a collection of genes. We need to start thinking about this as a cumulative loading of genetics.”

The work at KCL is still in its early stages. But it has been found there are 108 genes with changes in people with schizophrenia. Now, nine genes have been found across those with depression, and 20 in people who have bipolar disorder. There are almost certainly many more still to find and scientists say many of these genes will be shared across the different conditions.

Making sense of my genetic legacy is important, because it allows me to break away from the feelings of inevitability that depression gives you. Is this meant to happen? Am I meant to get over this? Is this bigger than me?

“Evidence from the last few years also suggests that many mental disorders share common genetic risk factors – for instance, genetic variation associated with schizophrenia overlaps with both depression and bipolar disorder,” says Lewis.

Siblings can have very different outcomes. Twins Lucy and Jonny have a bipolar mother. Jonny has also suffered from the condition, while Lucy has not.

Amphetamines And Other Stimulants

As amphetamines trigger the release of dopamine and excessive dopamine function is believed to be responsible for many symptoms of schizophrenia , amphetamines may worsen schizophrenia symptoms. Methamphetamine, a potent neurotoxic amphetamine derivative, induces psychosis in a substantial minority of regular users which resembles paranoid schizophrenia. For most people, this psychosis fades away within a month of abstinence but for a minority the psychosis can become chronic. Individuals who develop a long lasting psychosis, despite abstinence from methamphetamine, more commonly have a family history of schizophrenia.

Drugs such as ketamine, PCP , and LSD , have been used to mimic schizophrenia for research purposes. Using LSD and other psychedelics as a research model has fallen out of favor, as the differences between the drug-induced states and the typical presentation of schizophrenia have become clear. The dissociatives ketamine and PCP, however, are still considered to produce states that are remarkably similar, and are considered to be even better models than stimulants since they produce both positive and negative symptoms.

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Premorbid Cognitive And Scholastic Performance

Schizophrenia patients, when considered as a group, have intellectual impairments, some of which predate the onset of psychotic symptoms. Individuals who later develop schizophrenia have been found to perform below average on standardized measures of intelligence in childhood, adolescence and young adulthood, and to show lower premorbid IQ than the general population The lower the IQ, the higher is the risk for later development of schizophrenia.

Poor school performance can be seen as a premorbid sign. Repeating a grade, difficulties in completing the final level of schooling, and social and behavioural difficulties have also been found to be risk factors for developing schizophrenia. In the Northern Finland 1966 Birth Cohort, 14-year-olds who were below their expected normal grade were three times more likely to develop schizophrenia than those in their normal grade, but low school marks did not predict schizophrenia. Developmental continuity, indicated by early developmental deviation in the first year of life associated with lower school performance at age 16 years, has been found to be stronger among children who develop psychoses later in life than among normal controls and those admitted to hospital for non-psychotic psychiatric disorder.

What Causes Mental Illness To Run In Families

Schizophrenia: An Evolutionary Enigma  Brett

We do not fully understand what causes mental illness. Or why it can be passed on in families.

When a condition is passed on in families through genes, it is called hereditary.

As the table above shows, the chances of developing a mental illness could depend on you and your relatives genes.

It does seem that mental illness can be hereditary. But we do not fully understand how this works. Mental illness may be passed on in family members for different reasons, not just genes.

John is an identical twin. This means he and his brother Sam have the exact same genes. This is why they look the same. John has depression, but his brother Sam has never had any mental health problems. If mental illness only had a genetic cause, then John and Sam would both have depression.

Environmental factors, like loneliness or a stressful life event, can cause mental illness. If you have a family history of mental illness you have a higher chance of developing mental illness in these situations.

This doesnt mean that you will definitely develop a mental illness. People with no family history of mental illness can develop a mental illness too.

There are different ways of looking after your mental health, which are explained more further down this page.

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How Heritable Is Schizophreniajanuary 8 2007 : 45 Am Subscribe

this linknot that girlScience & Nature3 users marked this as a favoritehereditaryNIMH also says 10%jessamyn8:07 AMLadyBonita8:21 AMcgg8:44 AMfluffy battle kitten8:49 AMjacquilynne8:55 AM“…Because there is an element of trigger / environment / nurture in whether or not people will develop schizophrenia it may decrease the odds for the child if they’re not raised in that environment.”the rate of suicide in schizophrenics is much higher than it is for the general populationschizophrenia.compaulsc9:46 AM linkIn a study published in 2002 it was reported that among those individuals who were considered at high-risk for schizophrenia, those with poor relationships with their parents were more likely to develop schizophrenia than those who had reported a good one. The authors of this article suggest that positive parental relations may help to protect the individual from developing schizophrenia. In this study 23% of high-risk subjects with poor relationships with both parents developed schizophrenia versus only 7% of high-risk subjects with good parental relationships.Listener10:09 AMMany environmental factors have been suggested as risk factors, such as exposure to viruses or malnutrition in the womb, problems during birth, and psychosocial factors, like stressful environmental conditions.jacquilynne10:14 AMocchiblu10:31 AMtwistofrhyme10:48 AMThis page on schizophrenia.comnot that girl’spaulsc11:04 AMHeredity and the Genetics of Schizophrenia

Linkage Disequilibrium Mapping And Positional Cloning

Positional cloning is the primary strategy available for finding susceptibility genes for disorders with unknown pathophysiology. There are four stages involved in the whole process: genome scan, fine-mapping, LD mapping and functional genomics. Firstly multiple affected families are screened with a DNA marker map of all chromosomes and followed by fine-mapping in these candidate region, additional markers are genotyped 12 cM apart. The third stage is LD mapping to find the association of small sets of adjacent markers with disease, implicating one or two specific genes. Lastly functional genomics or physiological studies on animal model was initiated to establish the role of the gene and protein, effects of mutation on physiology and behaviour, and response to treatment for the disease.

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Environmental Factors That Exacerbate Schizophrenia

Environmental factors in the development of schizophrenia are just as complex as the genetic ones. A person who is biologically vulnerable to the issue might be greatly affected by any of these, or not at all. But if your parent has been diagnosed, and you know you are vulnerable, these are factors that might have an impact on whether you develop it or not.

  • Malnourishment in the womb
  • Infection passed down through mother while in the womb
  • Early loss of a parent
  • Poverty during childhood
  • Sexual, emotional, or physical abuse
  • Emotional neglect
  • Delusions
  • Excessive and irrational grandeur

If you are experiencing these, and know that you have a distinct vulnerability, its possible that you may be in the process of developing schizophrenia. However, whether it is schizophrenia or not, know that if you are experiencing a mental health issue, help is available. Healing is possible.

The Role Of Brain Chemistry And Structure In Schizophrenia

What is schizophrenia? – Anees Bahji

Scientists are looking at possible differences in brain structure and function in people with and people without schizophrenia. In people with schizophrenia, they found that:

  • Spaces in the brain, called ventricles, were larger.
  • Parts of the brain that deal with memory, known as the medial temporal lobes, were smaller.
  • There were fewer connections between brain cells.

People with schizophrenia also tend to have differences in brain chemicals called neurotransmitters. These control communication within the brain.

Studies show that these neurotransmitters are either too active or not active enough in people with schizophrenia.

Doctors also believe the brain loses tissue over time. And imaging tools, like PET scans and MRIs, show that people who have schizophrenia have less âgray matterâ — the part of the brain that contains nerve cells — over time.

Studies of brain tissue in people with schizophrenia after death even show that their brain structure is often different than it was at birth.

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Overlap With Other Disorders

Several studies have suggested a genetic overlap and possible genetic correlation between schizophrenia and other psychiatric disorders including autism spectrum disorder, attention deficit-hyperactivity disorder, bipolar disorder, and major depressive disorder. One genome-wide association study analyzed single-nucleotide polymorphism data for the five disorders four gene areas overlapped with the five disorders, two of which regulate calcium balance in the brain.

Risk Factors For Schizophrenia During Pregnancy And Delivery

Many pre- and perinatal risk factors for schizophrenia have been identified, although these tend to have a modest effect, with typical odds ratios or relative risks of 2. These factors include antenatal exposure to influenza, especially during second trimester, and other respiratory infections, rubella during pregnancy, hypoxia-related obstetric complications, low birth weight and prenatal growth retardation . So far, the evidence is less secure for antenatal stress and malnutrition in pregnancy.

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Base And Target Data: Quality Control And Exclusions

Blood samples from 488,366 UK Biobank participants were genotyped using the UK BiLEVE array or the UK Biobank axiom array. Further details on the genotyping and quality control can be found on the UK Biobank website . In the current study, SNPs were removed if they had missingness> 0.02 and MAF< 0.01. Samples were removed from the dataset if they had missingness> 0.01. We used a subset of European ancestry inferred individuals, defined using 4-means clustering applied to the first two PCs of the genotype data, because PRS are typically underpowered when applied to target samples of a different global ancestry to that of the base data using current PRS methods. Confirming this to be the case here, we repeated the analysis of the top 20 PRStrait associations in the full cohort including 20,798 non-European ancestry inferred individuals and observed less significant PRStrait associations in 12 of the 20 results despite the substantial increase in sample size . One of each pair of related individuals were removed using a relatedness criterion KING coefficient< 0.088. Exclusions based on heterozygosity and missingness were implemented according to UK Biobank recommendations . Samples were removed if they were discordant for sex. SNPs deviating from Hardy-Weinberg equilibrium were removed at a threshold of P< 108. This QC process resulted in a data set of 560,173 SNPs and 386,192 samples available for analysis.

Schizophrenia Treatment For Your Parentand You

Part 2: Typical vs atypical antipsychotics

If you have a parent who has paranoid schizophrenia, you should understand that:

  • It is not inevitable that you will develop it, too.
  • However, there is no cutoff for developing schizophrenia, either. Onset can occur at any age and at any time.
  • If you are vulnerable, be vigilant in checking in with yourself and taking note of possible symptomsespecially if you have experienced any of the precipitating environmental factors.
  • Hope, and help, are available for you both.
  • Schizophrenia cannot be cured, but there are treatment options that make it manageable. These include medications and psychotherapy. Medications are especially important for balancing out the neurochemical and essentially genetic components of schizophrenia. And the environmental factors are handled with long-term, residential treatment, which may include a variety of treatment modalities including one-on-one psychotherapy sessions. This psychotherapy, by a certified therapist with experience in schizophrenia, can help you understand the exacerbating incidents that made you move from vulnerable to symptomatic.

    A parent with a paranoid schizophrenia diagnosis doesnt mean that you will develop the symptoms. And even if you develop them, it doesnt mean you have no hope. Paranoid schizophrenia is treatable and manageable. Finding the right treatment is something you can find for yourself, and something you can pass on to your parent.

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    When A Parent Has Experienced Psychosis

    … What kids want to know

    Children have a lot of questions when someone in their family is sick. When children don’t have answers to their questions, they tend to come up with their own, which can be incorrect and scary!

    When a family member has had psychosis, it can easily become a secret that nobody talks about. All children need some explanation and support, geared to their age, to help them understand this disorder.Each parent and child’s first conversations about psychosis will be different. How you address the subject will depend on the child’s age and ability to manage the information-you know your child best. This brochure will help prepare you to take the first step in discussing this disorder with your child.

    In ‘hidden Valley Road’ A Family’s Journey Helps Shift The Science Of Mental Illness

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    Inside the Mind of an American Family

    Inside the Mind of an American Family

    There are still many questions about schizophrenia what it is, what causes it, and how to treat it.

    One family has helped researchers take steps forward in attempts to find answers to these questions.

    The Galvins seemed like a model for baby-boomer America, 12 children with a military dad and a strict but religious mother growing up in Colorado in the 1960s. But over the years, six of the boys in the family were diagnosed with schizophrenia.

    Writer Robert Kolker, the bestselling author of Lost Girls, tells the story of the Galvin family and how their journey is transforming the science around the mental illness in a new book, Hidden Valley Road: Inside the Mind of an American Family.

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    Migration And Substance Abuse Analyses

    Self-reported risk-taking was tested for association with the migration phenotypes using linear regression and with substance abuse using logistic regression. The control phenotypes that were used in this follow-up analyses, also tested via linear and logistic regressions, were: breast fed birth weight known birth weight left hand grip leg pain on walking blood pressure device ID and month attended assessment centre. Each of these phenotypes were then tested for an association with the schizophrenia PRS. All of the analyses were adjusted for age, sex, Townsend deprivation index and educational attainment, as described in the main text and corresponding table captions.

    Infections And Immune System


    A number of viral infections exposed to during prenatal development, have been associated with an increased risk of later developing schizophrenia. Schizophrenia is somewhat more common in those born in winter to early spring, when infections are more common.

    Influenza has long been studied as a possible factor. A 1988 study found that individuals who were exposed to the Asian flu as second trimester fetuses were at increased risk of eventually developing schizophrenia. This result was corroborated by a later British study of the same pandemic, but not by a 1994 study of the pandemic in Croatia. A Japanese study also found no support for a link between schizophrenia and birth after an influenza epidemic.

    Polio, measles, varicella-zoster, rubella, herpes simplex virus type 2, maternal genital infections, Borna disease virus, and Toxoplasma gondii have been correlated with the later development of schizophrenia. Psychiatrists E. Fuller Torrey and R.H. Yolken have hypothesized that the latter, a common parasite in humans, contributes to some, if not many, cases of schizophrenia.

    There is some evidence for the role of autoimmunity in the development of some cases of schizophrenia. A statistical correlation has been reported with various autoimmune diseases and direct studies have linked dysfunctional immune status to some of the clinical features of schizophrenia.

    Other factors

    A meta-analysis found that high neuroticism increases the risk of psychosis and schizophrenia.

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