Which Psychiatric Disorders Are Genetic?
Psychiatric disorders are complex diseases with various symptoms that are believed to be caused by both genetics and environmental influences.
Estimates from genome wide association studies (GWAS) show that hundreds of common variants each can play an impactful role in susceptibility to mental disorders 59.
These studies use DNA testing to detect subtle variations that appear more frequently among those living with an illness versus those without it.
Depression causes changes to the chemical balance in your brain that regulate mood, eating and sleeping patterns; it also disrupts your ability to think clearly and handle stress effectively. Depression typically starts in adulthood but may first emerge during childhood or adolescence. People affected by depression often feel sad or empty, have trouble focusing and remembering things and don’t enjoy participating in usual activities as before – they might feel worthless or guilty, believing nothing will ever change for the better.
Depression often runs in families, and studies indicate a link between certain genes on chromosome 3p25-26 and severe recurrent depression in certain families. But one single gene alone likely doesn’t cause depression; most likely genes interact with each other and the environment to increase the risk.
Anxiety is the most widespread psychiatric disorder and its genes have been identified, yet their significance in explaining anxiety disorders cannot be directly traced back. Life experiences also play a part in creating anxiety symptoms; stress-inducing situations often precipitate anxiety disorders.
Researchers have recently discovered that genetic variation is linked with multiple forms of anxiety phenotypes – generalized anxiety disorder and panic disorder as well as neuroticism, which strongly correlates with depression and PTSD psychiatric disorders. This “significant genetic overlap” suggests these conditions share similar biological causes despite having different DSM-5 classifications.
Researchers continue to investigate the heritability of anxiety; however, genetic studies of psychiatric disorders are difficult due to numerous genes contributing to it and each having an individual impact on risk.
Bipolar disorder is characterized by periods of elevated energy and elevated mood (mania), followed by periods of depression that interfere with their daily lives and lead to thoughts of suicide.
Studies on DNA samples collected from large groups of people demonstrate that certain variations of genes increase risk for bipolar disorder, but don’t fully account for it; its cause lies elsewhere, with multiple genes playing a part.
Studies of blood samples collected from thousands of people have also shown that stress increases the likelihood of having a mood episode. Symptoms tend to arise during periods of major change or stressors, such as getting married or moving house or experiencing relationship difficulties; they can also occur while taking drugs such as alcohol or recreational substances.
Scientists have discovered more than 100 genes linked to schizophrenia. Mutations in any of these genes may increase your risk for schizophrenia; environmental factors or brain development could trigger mutations and some could influence how well medications work for you.
Researchers are also conducting genome-wide association studies (GWAS), in order to discover which genes contribute to schizophrenia. For this analysis, samples of cases and controls with similar ages, gender and race have been used.
GWAS studies can identify common variations, like single nucleotide polymorphisms (SNPs), that alter how well genes function. Another group, such as the Psychiatric Genomics Consortium, utilizes data from whole genome sequencing to identify rare variants that could seriously disrupt gene function.
Autism spectrum disorder (ASD) is a developmental condition characterized by social challenges and restricted, repetitive behaviors, interests and activities. Scientists generally attribute autism‘s prevalence mainly to genetic factors; however environmental influences also play a part.
People with autism frequently engage in self-stimulating behavior such as flapping their hands, rocking their bodies or repeating certain actions over and over again. Stimming can provide enjoyment or help manage stress or anxiety levels.
Studies have revealed that some individuals with autism carry only one copy of neurexin 1, a gene which regulates how nerve cells communicate within the brain. Furthermore, another gene called CNTNAP2 may also contribute to autism symptoms.