Brain Volumes Affected by Type and Timing of Childhood Abuse
Maltreatment during childhood has been linked to brain changes and mental illness. In a study by researcher Carl M. Anderson and colleagues that was presented at the 2016 meeting of the Society of Biological Psychiatry, maltreatment at particular ages was statistically linked to deficits in the size of certain brain areas in young adulthood.
The brain areas under examination are critical for the regulation of emotion and behavior, and this research suggests that early experiences can stunt their development, perhaps through altered production of synapses or via the synaptic pruning process that occurs during preadolescence. The details, summarized below, are perhaps less important than the overall finding that maltreatment in childhood affects brain volume, and this effect varies based on the timing and type of maltreatment. Abuse and neglect earlier in life affected the left side of the brain, while later maltreatment affected the right side.
Severity of physical abuse at age 3 affected the volume of the ventromedial prefrontal cortex in women. Physical abuse at ages 3 and 8 in men affected left ventromedial prefrontal cortical volume, while later abuse at ages 7 and 12 predicted volume of the right side.
In women, dorsal anterior cingulate area on the left was predicted by physical abuse at age 5 and by emotional neglect at ages 7 and 11. Later emotional neglect at ages 15 and 16 and physical abuse by a peer at age 10 was associated with smaller right dorsal anterior cingulate. In men, smaller left dorsal anterior cingulate area was predicted by physical neglect at age 2 and emotional abuse by a peer and witnessing abuse of a sibling at ages 5 and 10, and right area by physical neglect at age 12.
Early Life Stress Affects Volume of the Hippocampus
New research shows that there are crucial periods of early life in which a stressful event can reduce hippocampal volume in adolescence. In a study presented at the 2016 meeting of the Society of Biological Psychiatry, Kathryn L. Humphreys and colleagues found that children who experienced a significant stressor before age 8 had smaller hippocampi in early adolescence than children who did not have a significant stressor early in life.
The severity of the stressors that occurred when children were between the ages of 0 and 2 predicted the volume of the hippocampus later in life. This was true to a lesser extent for stressful events that occurred between the ages of 3 and 5. No effect was seen for stressful events that took place between the ages of 6 and 8.
The period of sensitivity to stressful events between ages 0 and 2 and its effects on hippocampal volume could influence a variety of psychiatric outcomes in conditions such as depression and post-traumatic stress disorder (PTSD).
Amygdala Hyperactivity Linked to Family History of Depression
In new research presented at the 2016 meeting of the Society of Biological Psychiatry, researcher Tracy Barbour and colleagues revealed that youth with a family history of depression showed more amygdala activation in response to a threat than people without a family history of depression. This amygdala hyperactivity was linked to low resilience to stress and predicted worsening depressive symptoms over the following year.
In the study, 72 non-depressed youth were shown images of cars or human faces or cars that seemed to loom in a threatening way. Brain scans showed increased amygdala activity in participants with a family history of depression compared to those without such a history.
The amygdala is an almond-shaped part of the brain in the temporal lobe that has been linked to emotional reactions and memory, decision-making, and anxiety.
IL-6 in Blood and Bone Marrow Linked to Lack of Resilience to Stress
Rodents who are repeatedly defeated by larger animals often exhibit depression-like behaviors. In new research that researcher Georgia E. Hodes presented at the 2016 meeting of the Society of Biological Psychiatry, animals who are susceptible to these social defeat stress behaviors showed immune irregularities, including high levels of the inflammatory marker interleukin-6.
An intervention to prevent the mice from secreting interleukin-6 in blood and bone marrow took away their susceptibility to social defeat stress. When bone marrow from rodents with no interleukin-6 was transplanted into susceptible mice, the recipients showed resilience to social defeat stress. Conversely, a transplant from susceptible mice to those mice without IL-6 led to social defeat stress in the previously “immune” mice.
This research shows that the peripheral immune system, including blood and bone marrow, plays an important role in depression-like behaviors in mice.
Child Abuse Linked to Adolescent Obesity
New research clarifies how trauma in early life can lead to obesity in adolescence. In a study of 160 young people between the ages of 9 and 15, researcher Janitza Montalvo-Ortiz and colleagues identified seven sites in the genome where DNA methylation predicted body mass index (BMI) in adolescence. The researchers also collected information on family traumas that occurred during the participants’ childhoods and found that DNA methylation and family trauma such as child abuse interacted to predict BMI.
Epigenetics describes the ways life experiences can change how easily DNA is turned on or off. While the genes coded by DNA sequences one inherits from one’s parents never change, the structure of DNA can change. DNA methylation is one type of epigenetic change that refers to the addition of methyl groups to promoter regions of DNA in response to life events.
In this research, which was presented at the 2016 meeting of the Society of Biological Psychiatry, Montalvo-Ortiz and colleagues found that the site of DNA methylation with the strongest link to BMI in adolescence was a gene called MAP2K3. This gene had previously been linked to obesity, but this is the first time DNA methylation at this site has been linked to both obesity and childhood trauma. Other relevant gene sites where DNA methylation occurred include ANKRD2, CPXM2, NUBPL, and RFK.
Certain Types of Inflammation and BMI Predict Depression
At the 2016 meeting of the Society of Biological Psychiatry, researcher Femke Lamers and colleagues presented findings from the Netherlands Study of Depression and Anxiety. The inflammatory markers interleukin-6 and CRP were elevated in people with current major depression. These measures were correlated with BMI, a measure of body weight. High levels of interleukin-6 at the beginning of the study predicted who would have a chronic course of illness.
Editor’s Note: Previous studies have found that elevated levels of CRP predicted a future mood episode in people at high risk for bipolar disorder due to a family history of the illness.
These studies suggest that it might be useful to assess levels of these inflammatory markers (CRP, interleukin-1, interleukin-6, and TNF-alpha) in young people who are at high risk for bipolar disorder. Factors that put someone at high risk include a family history of depression or bipolar disorder, a history of adversity in childhood (abuse, neglect, loss of a parent, etc.), and preliminary symptoms.
Several interventions are available that may reduce the likelihood that someone at risk for bipolar disorder will go on to develop the illness. Family interventions such as the Family Focused Therapy developed by researcher David Miklowitz are helpful. In a 2013 study in the Journal of the American Academy of Child and Adolescent Psychiatry, Miklowitz reported that Family Focused Therapy outperformed treatment as usual for youth at risk for bipolar disorder.
Measures of inflammation might provide additional rationale for beginning interventions in youth at high risk for mood disorders. In addition to family interventions, omega-3 fatty acid supplementation is a low-risk option that is supported by some positive data. Since BMI was implicated in the study by Lamers and colleagues, keeping weight under control might also have some benefit.
For adults with depression who want to keep their weight under control, the combination of the antidepressant bupropion XR (150–300mg/day) and naltrexone (50mg/day), an opiate antagonist medication normally used to fight addictions, has been effective.
Emotional Abuse Increases Inflammation
Trauma in childhood is a risk factor for depression, and both childhood trauma and depression have been linked to increased inflammation. In a study presented at the 2016 meeting of the Society of Biological Psychiatry, Sarah R. Horn and colleagues found that emotional abuse in childhood predicted high levels of inflammation measured in the blood in adulthood.
Horn and colleagues took blood samples from 35 people with treatment-resistant depression and 28 healthy control subjects. The researchers measured inflammatory markers in the blood and also interviewed the participants about any physical, sexual, or emotional abuse they experienced in childhood. Among all the participants, emotional abuse was linked to elevated levels of several inflammatory markers, including interleukin-6, interleukin-10, interleukin-1a, interleukin-15, and fractalkine.
The researchers suggest that more research is needed to clarify the link between early trauma, depression, and inflammation. How elevated inflammation in people with a history of abuse may influence the effectiveness of different psychotherapies and medications for depression remains to be determined.
Mothers Who Were Abused in Childhood Secrete Less Oxytocin While Breastfeeding
A recent study suggests that women who experienced moderate or severe abuse in childhood secrete less oxytocin while breastfeeding their own children. Oxytocin is a hormone that promotes emotional bonding. The study included 53 women. They breastfed their newborn children while blood samples were collected from the women via IV. Those women with a history of moderate or severe abuse (emotional, physical, or sexual) or neglect (emotional or physical) had lower measures of oxytocin in their blood during breastfeeding than women with no history or abuse in childhood or a history of mild abuse.
A history of abuse or neglect was more common among women with current depression compared to women with a history of depression or anxiety. Women who had never experienced depression or anxiety were least likely to have a history of abuse or neglect.
The study by Alison Steube and colleagues, presented at the 2016 meeting of the Society of Biological Psychiatry, suggests that traumatic events that occur during childhood may have long-lasting effects. These experiences may modulate the secretion of oxytocin in adulthood. Low oxytocin has been linked to depression.
SSRI Use During Pregnancy Linked to Adolescent Depression in Offspring
A 2016 article by Heli Malm and colleagues in the Journal of the American Academy of Child and Adolescent Psychiatry suggests that in utero exposure to selective serotonin reuptake inhibitor (SSRI) antidepressants may increase the risk of depression in adolescence. However, the study included potentially confounding factors. It is possible that women who took SSRIs during pregnancy had more severe depression than those who went unmedicated during pregnancy. The mothers in the study who took SSRIs also had more comorbid conditions such as substance abuse.
Editor’s Note: Women should balance the risks and benefits of antidepressant use during pregnancy, since depression itself can have adverse effects on both mother and fetus. It has recently been established that SSRI use during pregnancy does not cause birth defects, so women with depression that has not responded to non-pharmaceutical interventions such as psychotherapy, omega-3 fatty acid supplementation, exercise, mindfulness, and repeated transcranial magnetic stimulation (rTMS) may still want to consider SSRIs.
Vegan Diet Can Lead to Vitamin B12 Deficiency
Foods high in vitamin B12
Vitamin B12 deficiency is a risk associated with a vegan diet. B12 deficiency can lead to depression, anemia, and even irreversible neuron damage, according to researcher Drew Ramsey, who spoke on the topic at the 2016 meeting of the American Psychiatric Association.
A study of vegans showed that 52% were deficient in vitamin B12, while another 23% had insufficient levels of the vitamin. B12 is found in the highest concentrations in certain seafoods and liver. It is also found in dairy products, eggs, fortified breakfast cereals, and is available in supplement form.
Women who eat a vegan diet while pregnant may not be providing their offspring with enough nutrients, according to researcher Emily Deans, who also spoke at the meeting. A case report on 30 vegan mothers found that 60% of their offspring had developmental delays and 37% showed cerebral atrophy.
Deans said that eating no meat is associated with higher rates of depression, anxiety, and worse quality of life.
Ramsey believes that while the North American diet is probably weighted too heavily toward animal products, seafood remains an important source of B12.
