At the 2014 meeting of the International College of Neuropsychopharmacology, researcher Booij reported that in humans, there is an interaction between adversity experienced during childhood, and an epigenetic variation in the short form of the serotonin transporter (5HT-T ss, or SLC6A4), which can influence hippocampal volume during depression.
Epigenetics refers to environmental influences on the way genes are transcribed. The impact of life experiences such as stress is not registered in DNA sequences, but can influence the structure of DNA or tightness of its packaging. Early life experiences, particularly psychosocial stress, can lead to the accumulation of methyl groups on DNA (a process called methylation), which generally constricts DNA’s ability to start transcription (turning on) of genes and the synthesis of the proteins the genes encode. DNA is tightly wound around proteins called histones, which can also be methylated or acetylated based on events in the environment. When histones are acetylated, meaning that acetyl groups are attached to them, DNA is wound around them more loosely, facilitating gene transcription (i.e. the reading out of the DNA code into messenger RNA, which then arranges amino acids in order to construct proteins). Conversely, histone methylation usually tightens the winding of DNA and represses transcription.
Booij followed 33 children who had experienced some form of adversity at a young age until they were 15 or 16, examining methylation of the serotonin transporter in their T cells and monocytes compared to 36 children who had not experienced adversity during childhood. He found that in children who had experienced abuse in childhood, the degree of that abuse was correlated with methylation of the serotonin transporter and was inversely related to the volume of the hippocampus, as measured using magnetic resonance imaging (MRI). Thus, child abuse yields lasting epigenetic effects (methylation of the serotonin transporter) and has anatomical consequences in teenagers, as seen in smaller hippocampi. These data parallel converse findings by Joan Luby et al. published in the journal PNAS in 2012, in which increased maternal warmth directed toward a child aged 4-7 was associated with increased volume of the hippocampus several years later.
Korea, like the US, has a moderate incidence of childhood-onset bipolar disorder among children who are at high risk because they have a parent with bipolar disorder. In a recent study by Young-Sun Cho et al. presented at the 2014 meeting of the International College of Neuropsychopharmacology (CINP), 59 out of 100 children with a parent who had been diagnosed with bipolar disorder met the criteria for a mental disorder themselves.
Mood disorders were most common. Of the 59 children with mental disorders, 22 were diagnosed with bipolar disorder, and 16 were diagnosed with a depressive disorder. Others included four with attention deficit hyperactivity disorder (ADHD), four with an anxiety disorder, two with disruptive behavior disorders, one with a tic disorder, one with an autistic disorder, and one with schizophrenia and an anxiety disorder.
Editor’s Note: In contrast to studies in Germany, Switzerland, the Netherlands, and Canada, where few children are diagnosed with bipolar disorders (even among those who are at high risk because of a family history of bipolar disorder), 22% of high-risk children in Korea were diagnosed with bipolar disorder. This is comparable to or higher than rates at which high-risk children in the US are diagnosed with bipolar disorder. Studies from both the Bipolar Collaborative Network (in which this editor Robert Post is an investigator) and researcher Boris Birmaher et al. found that parents with bipolar disorder often had a variety of other disorders, such as anxiety, alcohol abuse, or substance abuse. These other illnesses also increase the risk of early-onset bipolar disorder in offspring, and this may account for the higher incidence of early-onset bipolar disorder among high-risk children in the US.
A decade ago the Federal Drug Administration (FDA) released several warnings that children, adolescents (ages 10–17), and young adults (ages 18-29) taking antidepressants were at increased risk for suicidal ideation and behavior. A recent study found that following these warnings, antidepressant use among adolescents, young adults, and adults dropped, and psychotropic drug poisonings (a validated measure of suicide attempts) increased among adolescents and young adults. Numbers of completed suicides did not change for any age group.
The decision to place the warnings on antidepressant packaging was somewhat controversial because it was based on studies that were not necessarily designed to measure suicide risk. The relationship between depression, medication, and suicide is complicated. Medication can improve mood, but patients may seek out medication because of pre-existing suicidal thoughts, and the medication may not reduce these in young people.
The reduction in antidepressant use that occurred after the warnings was accompanied by a drop in depression diagnoses in children and adults. Studies have suggested that the decreases in antidepressant were not accompanied by increases in other treatments, such as psychotherapy or atypical antipsychotics, among young people. Increased monitoring of patients was called for in the FDA’s box warning, but did not take place.
The study of the aftermath of the FDA warnings, published by Christine Y. Lu et al. in a 2014 article in the journal BMJ, used data from 11 insurance networks throughout the US. The researchers used an interrupted time series study design, which is used to show whether a policy causes an abrupt change in the expected slope of study outcomes. Data covered the pre-warning period (first quarter of 2000 to third quarter of 2003), the warning “phase-in” period (last quarter of 2003 to last quarter of 2004) and the post-warning period (first quarter of 2005 to last quarter of 2010). The study cohorts included around 1.1 million adolescents, 1.4 million young adults, and 5 millions adults per quarter.
Among adolescents, the previously upward trend in antidepressant use declined by 31.0% in the second year after the warnings, and psychotropic drug poisonings increased by 21.7% (a figure that was statistically significant for males). Poisonings by any drug increased by 13.9% in the second year after the warnings. After 2008, the downward trend in antidepressant use reversed, indicating that either the initial effects of the warning had worn off or that modifications to the warnings in May 2007, which encouraged patients and doctors to consider the risk of antidepressants alongside the risk of leaving mood disorders untreated, led to increased use.
Among young adults, the upward trend in antidepressant use declined by 24.3% in the second year after the warnings, and psychotropic drug poisonings increased by 33.7%, a statistically significant change for both male and female patients.
Among adults, to whom the warnings were not directed, antidepressant use decreased by 14.5% in the second year after the warnings.
The study by Yu et al. is the first to show that suicide attempts actually increased after the FDA warnings. The authors suggest that the increase in suicide attempts might be a consequence of undertreating mood disorders, since antidepressant use dropped simultaneously. The warnings and related media attention may have led to these unintended consequences, since media reports can sometimes be oversimplified.
Type 2 diabetes can damage the brain, particularly by reducing volume of the hippocampus, and frequently occurs in patients with bipolar disorder. A recent study of patients with bipolar disorder and abnormal glucose metabolism showed that patients with bipolar disorder who also had insulin resistance, glucose intolerance, or type 2 diabetes had smaller hippocampi than both patients with bipolar disorder and normal glucose function and normal control participants without a psychiatric disorder. In those with bipolar disorder and glucose abnormalities, age was associated with lower hippocampal volume to a greater extent than in bipolar patients with normal glucose function.
In the study, published by Tomas Hajek et al. in the journal Neuropsychopharmacology, not only did diabetes or prediabetes reduce the size of the hippocampus, but also reduced gray matter in the cerebral cortex, including the insula.
The researchers hope that treating diabetes, or possibly even its initial symptoms, more effectively may prevent these gray matter losses and slow brain aging in patients with bipolar disorder.
In a 2013 article in the journal European Psychiatry, in which researcher Valery V. Gafarov examined depression’s influence on cardiovascular health in Russia, an astonishing 55.2% of women aged 25–64 years in the study were diagnosed with depression. The study, in which 870 women in the city of Novosibirsk were surveyed over 16 years from 1995 to 2010, was part of a World Health Organization program called “MONICA-psychosocial.”
The researchers collected information on the incidence of myocardial infarction (heart attack), arterial hypertension, and stroke among the women. Over the 16 years of the study, 2.2% of the women had heart attacks and 5.1% had strokes. Women with depression were 2.53 times more likely to have a heart attack and 4.63 times more likely to have a stroke than women without depression.
Among women with average education levels, married women with depression were more likely to have heart attacks, hypertension, and strokes. Hypertension was more likely among women who worked as managers or light manual laborers.
C-reactive protein, or CRP, is a protein found in blood plasma, the levels of which rise in response to inflammation. In a recent study, levels of CRP were able to predict which of two antidepressants a patient was more likely to respond to.
The 2014 article by Rudolph Uher et al. in the American Journal of Psychiatry reported that low levels of CRP (<1 mg/L) predicted a good response to the selective serotonin reuptake inhibitor (SSRI) escitalopram (Lexapro) while higher levels of CRP predicted a good response to the tricyclic antidepressant nortriptyline, a blocker of norepinephrine reuptake.
The research was part of the Genome-Based Therapeutic Drugs for Depression (GENDEP) study, a multicenter open-label randomized clinical trial. CRP was measured in the blood of 241 adult men and women with major depressive disorder. In the article the researchers say that CRP and its interaction with medication explained more than 10% of the individual variance in response to the two antidepressants.
If these findings can be replicated with these and similarly acting drugs, it would be a very large step in the direction of personalized medicine and the ability to predict individual response to medications.
Some people have found that gluten-free or casein-free diets have improved their intestinal, autoimmune, or neurological symptoms. (Casein is a protein found in mammals’ milk. Cow milk is high in casein while human milk proteins are 20–45% casein.) One explanation for the good effects of these diets is that peptides that are released during digestion of these foods can create epigenetic changes in gene expression, adding methyl groups to DNA strands that increase inflammation.
As infants transition from getting all of their nutrition from the placenta to using their gastrointestinal tract, their diet may lead to epigenetic modifications that affect their health later in life. Epigenetics refers to changes in genes that do not affect the inherited sequence of DNA, but affect how easily the DNA is transcribed to produce proteins. Methyl or acetyl groups can be added to DNA or the histones around which it is wound.
When a person digests casein (from either human or animal milk) or gliaden (a protein derived from wheat), peptides are released that activate opioid receptors, modulating the uptake of the amino acid cysteine in neurons and in the gastrointestinal tract. This decrease in cysteine uptake is associated with drop in the antioxidant glutathione and a methyl donor (a molecule with a reactive methyl group that can easily become part of another molecule) called S-Adenosyl methionine.
In addition to decreasing cysteine uptake, the peptides also increase DNA methylation and create epigenetic changes in genes involved in redox (changes in oxidation) and methylation homeostasis.
These processes are described in a 2014 article by Malav S.Trivedi et al. in the Journal of Nutritional Biology. Trivedi et al. conclude that milk and wheat can change antioxidant activity and gene expression. Differences in the peptides in human and cow milk may explain developmental differences between children who are breastfed and those who receive formula.
The decrease in antioxidants caused by peptides from wheat and milk can predispose people to inflammation and oxidation, explaining why wheat- or casein-free diets might be useful.
Epidemiological studies have linked methamphetamine use to risk of Parkinson’s disease, and animal studies of the illicit drug have shown that it harms dopamine neurons. A 2014 study by Sara Ares-Santos et al. in the journal Neuropsychopharmacology compared the effects of repeated low or medium doses to those of a single high dose on mice. Loss of dopaminergic terminals, where dopamine is released, was greatest after three injections of 10mg/kg given at three-hour intervals, followed by three injections of 5 mg/kg at three-hour intervals, and a one-time dose of 30mg/kg. All of the dosages produced similar rates of degeneration of dopamine neurons via necrosis (cell destruction) and apoptosis (cell suicide) in the substantia nigra pars compacta (the part of the brain that degenerates in Parkinson’s disease) and the striata.
A symposium at the 2014 meeting of the American Psychiatric Association suggested that resilience may hold the key to healthy aging, and overcoming trauma and stress.
Resilience in Aging
Former APA president Dilip Jeste began the symposium with a discussion of successful aging. He noted the importance of optimism, social engagement, and wisdom (or healthy social attitudes) in aging. In a group of 83-year-olds, those with an optimistic attitude had fewer cardiovascular illnesses, less cancer, fewer pain syndromes, and lived longer. Those with high degrees of social engagement had a 50% increase in survival rate. Wisdom comprises skills such as seeing aging in a positive light, and having a memory that is biased toward the positive (the opposite of what happens in depression, where negatives are selectively recalled and remembered). Jeste encouraged psychiatrists to focus not just on the treatment of mental illness, but on behavioral change and the enhancement of wellbeing. He suggested asking patients not just, “How do you feel?” but instead, “How do you want to feel?”
Resilience in the Military
Researcher Dennis Charney gave a talk on resilience based on his work with people in the military, some of whom experienced post-traumatic stress disorder (PTSD). He cited a series of important principles that could enhance resilience. The first principle was to reframe adversity—assimilating, accepting and recovering from it. The second principle was that failure is essential to growth. The third principle was that altruism helps, as does a mission for the survivor of trauma. Charney suggested that a personal moral compass is also critical, whether this is based on religion or general moral principles. Other factors that are important for resilience include having a role model, facing one’s fears, developing coping skills, having a support network, increasing physical well-being, and training regularly and rigorously in multiple areas.
Charney and colleagues studied Navy SEALS who went through SERE (Survival, Evasion, Resistance, Escape) training. Those SEALS who had the highest resilience during this severe training exercise had the highest levels of the neurotransmitter norepinephrine and NPY (an antianxiety neuropeptide). NPY levels are low in people with PTSD. Charney and colleagues reasoned that giving a peptide that acted on the NPY-1 receptors intranasally (so that it could cross the blood brain barrier) might be therapeutic. In a rodent model of PTSD, the peptide prevented and reversed PTSD-like behaviors. Further clinical development of the peptide is now planned.
The Effects of Stress
Researcher Owen Wolkowitz described how stress accelerates the mental and physical aspects of aging. Telomeres are strands of DNA at the end of each chromosome that protect the DNA during each cell replication. Telomere length decreases with stress and aging. Read more
Not everyone who experiences trauma develops post-traumatic stress disorder (PTSD) immediately. Researchers are discovering that some people go on to develop symptoms like flashbacks or intrusive thoughts, anxiety, and withdrawal, sometimes after long periods of being asymptomatic. Two studies provide hints about the mechanism of this late-onset (or delayed-type) PTSD.
In an article by Danny Horesh et al. published in the journal Psychiatry Research in 2013, a reported 16.5% of 675 Israeli veterans of the 1982 conflict with Lebanon developed late-onset PTSD after a completely non-symptomatic period. The number of deployments soldiers were sent on and the number of terror incidents they experienced within Israel after the war were correlates of the late-onset PTSD, while continuous post-war employment was a protective factor reducing late-onset PTSD.
In a study of 260 older adults (above age 60) who survived the destruction around Galveston Bay, Texas by Hurricane Ike in 2008, Robert H. Pietrzak et al. reported in the Journal of Psychiatry Research in 2013 that 5.3% developed late-onset PTSD. In this case as well, a greater number of subsequent traumatic and stressful life events (and in particular financial difficulties) was associated with late onset of PTSD. The majority of participants in Pietrzak’s study (78.7 %) had no to few PTSD symptoms, while 16.0% had chronic PTSD symptoms from the outset persisting through assessments at three months and 15 months.
Editor’s Note: These two studies reveal that upon prospective follow-up, a small but substantial group of patients (5–16%) develop a late-onset type of PTSD. Acute onset PTSD has been closely linked to new trauma in adulthood, especially following the occurrence of previous (childhood) traumas. The late-occurring variety of PTSD seems to appear after an incubation period, and appears to be closely associated with the occurrence of new traumatic events during the well interval. These new events may result in a kindling-like effect, where repetition of subthreshold stimuli come to evoke a full-blown episode. PTSD appearing after repeated traumatic experiences may operate in a similar fashion to seizures that gradually emerge following repeated electrical stimulation of the amygdala (i.e. amygdala kindling). Read more