Information about these techniques was expected to be presented Tuesday during a news conference by researchers taking part in U.S. National Institute of Mental Health symposiums at the American Psychiatric Association annual meeting, in Washington, D.C.

"These studies contribute new information about how the brain malfunctions in depression and bipolar disorder, what goes wrong with brain chemicals, and where in the brain the problems arise," Dr. Ellen Leibenluft, of the NIMH, said in a prepared statement. "We find that the brain systems involved and the exact nature of the difficulties differs among patients, even when those patients have similar symptoms. Eventually, data like these will allow us to develop more individualized and targeted treatments for depression."

In one study, University of Michigan researchers using molecular imaging with positron emission tomography (PET) found that patients with untreated major depression had an overall reduction in the concentration of serotonin 1A receptors in the hippocampus, a brain region that helps regulate stress.

"The reductions in these receptors were correlated with the functional impairment of the patients in work and with their families, with greater impairment being associated with lower receptor concentrations in this region," study author Dr. Jon-Kar Zubieta said in a prepared statement.

The patients responded to treatment with citalopram.

In another study, Zubieta and colleagues found that people with untreated major depression had reduced concentrations of "mu" opioid receptors in the thalamus, an area of the brain involved in the regulation of emotions. The mu receptors play a key role in regulating mood and triggering brain reward systems. A reduction in the receptors was associated with greater concentrations of stress hormones.

The researchers also found that depressed patients who didn't respond to the antidepressant fluoxetine (Prozac) had lower concentrations of mu receptors in the anterior cingulate, an area of the brain involved in the processing of emotional states.

In other studies, NIMH researchers used PET and functional MRI to identify abnormal patterns of neural activity and chemical function in the brain's reward pathway that underlie depressed patients' inability to experience pleasure.

"The identification of brain systems and circuits whose activity can be correlated with specific symptoms is a first step toward the development of more targeted and effective treatments for depression and other disorders of the brain," Dr. Wayne Drevets, of the NIMH, said in a prepared statement.

In another study, Yale School of Medicine researchers using specialized applications of MRI found that people with bipolar disorder have reduced volume of the brain's prefrontal cortex and its subcortical connections sites, including the amygdala.

Previous research found that patients with bipolar disorder have abnormal functioning of these brain structures, especially during the processing of emotional stimuli and during tasks that require inhibition of impulsive responses.

In other studies, scientists found that fMRI can help determine whether children have biploar disorder or severe irritability with attention-deficit hyperactivity disorder (ADHD). This suggests that brain imaging may prove useful in making a correct diagnosis.

"We're finding that these very irritable children with ADHD share some characteristics with children with bipolar disorder but also have significant differences," said Leibenluft.

Children with these conditions are easily frustrated, have difficulty reading facial emotional cues, and have social cognition deficits.

"Yet what's happening in the brain during frustration differed between the two groups. So these data indicate that, even when two groups of patients exhibit the same symptoms, the brain mechanisms underlying that symptom can differ. Data like these indicate how, eventually, psychiatric diagnosis will be based on brain mechanisms, in addition to symptoms," Leibenluft said.

More information

The U.S. Center for Mental Health Services has more about mood disorders.

But that risk is moderate, emphasized the authors of a study in the May issue of Archives of Pediatrics & Adolescent Medicine.

"Most adoptees are doing fine," said Margaret Keyes, lead author of the study and research psychologist at the Minnesota Center for Twin and Family Research at the University of Minnesota in Minneapolis. Still, new data on the long-term health of adopted children is always useful, she reasoned.

"When you have all the information, you're better prepared to make decisions for your family," Keyes said. "You have information that your adopted child might be at a slightly increased risk, so you can be aware of that and can you use the social services agencies with which you already familiar through the process of adopting."

"There is no revelation here. This is consistent with previous research," added Adam Pertman, executive director of the Evan B. Donaldson Adoption Institute and author of Adoption Nation. "It's a good, solid piece of work. Adoptive parents can be reassured that their kids will be just fine, thank you. We do need to do a better job of learning how to deal with children and be prepared in case we are in that minority whose kids are represented in this study. It's not scary. It's cautionary."

According to background information in the article, some 120,000 children are adopted annually in the United States, and there are about 1.5 million adopted American children under the age of 18.

International adoptions are increasingly replacing domestic adoptions, with about 40,000 children transferred between more than 100 countries each year as a result of adoption.

Although some studies have found an increased risk of social, intellectual and emotional problems among children who were exposed to substances before they were born or who were neglected prior to adoption, the risk among children who don't have this kind of history hasn't been clear.

The researchers assessed 514 internationally adopted adolescents and 178 domestically adopted adolescents (aged 11 to 21) and compared them with 540 non-adopted kids of the same age.

Children who had been adopted scored higher than non-adoptees on continuous measures of behavioral and emotional problems, the team found. Adoptees were about twice as likely to have had contact with a mental health professional and of having a disruptive behavior disorder, according to the study.

Domestic adoptees were more than twice as likely to have an "externalizing disorder" (one that manifests in outward behavior) than international adoptees, the researchers added.

As one example, seven out of every 100 non-adopted kids met the criteria for ADHD (attention deficit hyperactivity disorder), while 14 to 15 of adopted kids met the criteria, Keyes said. Still, the overall rate was not alarming.

To put it into perspective, Keyes pointed out that simply giving birth to a male is risky, since boys have a higher chance of being diagnosed with a disruptive behavior disorder than girls.

"It's important not to stigmatize adoption," Pertman said. "Adoption is not causing these problems."

A second study in the same issue of the journal looked at children who had lost a parent to death suddenly. Researchers at the University of Pittsburgh School of Medicine found that these bereaved youngsters had triple the risk of depression and post-traumatic stress disorder (PTSD) than kids with two parents still alive.

According to the article, 4 percent of children in Western countries have experienced the death of a parent.

More information

There's more on adoption at the Evan B. Donaldson Adoption Institute.

The guidelines are meant to address mounting fears that these medications can raise the risk for cardiac complications among those with underlying heart disease.

"This is new, and it is a shift in our policy," said Dr. Victoria L. Vetter, head of the association's statement writing committee, and a professor of pediatrics at the University of Pennsylvania School of Medicine in Philadelphia.

"But we're not recommending that every child in the country have these heart screenings, rather that they be used as a reasonable tool for this small, particular group of children about to take ADHD medications, so we can ensure the treatment proceeds as safely as possible," she added.

The recommendations were published online Monday in Circulation, a journal of the American Heart Association (AHA).

They include: the taking of a detailed patient and family medical history, particularly regarding heart disease; a full physical exam, including blood pressure and heart beat monitoring; an electrocardiogram (ECG); and a pediatric cardiologist consultation prior to treatment if evidence of heart disease is uncovered.

After treatment begins, the AHA said that children should continue to have blood pressure check-ups once every one to three months, as well as routine health check-ups every six to twelve months.

The AHA noted that ADHD is the most common neurobehavioral disorder among American kids, with estimates indicating that between 4 percent and 12 percent of American school-aged children have the condition.

Currently, more than 2.5 million children in the United States are being prescribed ADHD medications, the organization noted.

According to the U.S. National Institutes of Health (NIH), the most effective ADHD medications typically belong to the "stimulant" class of drugs, which includes amphetamines, methylphenidates and dextroamphetamines.

Some of the names under which these drugs are marketed include Adderall, Concerta, Dexedrine, Focalin, Ritalin, Ritalin SR or LA, and Metadate ER or CD. The new recommendations refer to all of these stimulants, as well as to a newer drug known as Strattera, which was recently approved by the U.S. Food and Drug Administration as a non-stimulant treatment for ADHD.

Though ADHD stimulants increase a child's heart rate and blood pressure, the NIH noted that no evidence has indicated that such medications are addictive, and side effects do not typically pose any danger for most healthy children.

However, children with underlying heart disease who take stimulants for ADHD appear to face an increased risk for sudden cardiac arrest, the AHA noted. This risk association is particularly troublesome for young ADHD patients, because heart disease often goes undiagnosed in children and may be present without noticeable symptoms.

The AHA also pointed to a number of studies that suggest that between 33 percent and 42 percent of pediatric heart patients also have ADHD.

FDA data collected for the period 1999 through 2004 revealed that 19 children following an ADHD prescription regimen had died suddenly, while 26 experienced heart complications such as stroke, heart attack, and/or heart palpitations.

Vetter noted that, in 2005, the Canadian equivalent of the FDA -- Health Canada -- decided to place a ban on Adderall, an amphetamine-based ADHD medication designed for kids over the age of 3. The Canadian decision was actually based on a review of FDA records concerning 12 reported deaths among American children taking ADHD drugs.

Vetter pointed out that the Canadian decision was based on an assessment of collected data based on family self-reports (sometimes in the absence of autopsy records), rather than a complete scientific analysis.

"But the reality is that we were faced with some kids who had ADHD who suddenly died," she said. "And a lot of them were exercising at the time, which is when most of the kids who have electrical malfunctions of the heart would have a sudden cardiac death. So we have to assume they experienced a cardiac death."

In February 2007, the FDA ordered makers of ADHD medications to develop guidelines that alert patients to the heart risks associated with their treatments.

"But it's not that these are dangerous medicines," stressed Vetter. "But by adding the ECG, and by being aware of possible heart disease, and monitoring the kids once you prescribe the medications, one can go ahead and treat the ADHD. And these kids can be very happy."

Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at Schneider Children's Hospital in New Hyde Park, N.Y., agreed that the point of expanded screenings is to identify a child's underlying heart complication, not to look for problems with the stimulants themselves.

"Serious cardiac complications from stimulant medications are very rare," Adesman said. "But because there are concerns on the part of parents and some physicians, routine ECG screenings will provide greater reassurance for the vast majority of patients for whom ADHD medications are being considered."

More information

For more on ADHD treatments, visit the National Institute of Mental Health.

The report, which was funded by the National Institutes of Health, is published in the March issue of the American Journal of Psychiatry.

"The results should reassure clinicians who might be hesitant to treat ADHD because of concerns about future substance abuse," said study co-author Michael C. Monuteaux, assistant director of research at the pediatric psychopharmacology program at Massachusetts General Hospital.

Past research looking for a link between ADHD medications and substance abuse has produced conflicting conclusions.

"Some previous studies showed an increased risk of substance abuse associated with stimulant treatment, and other studies showed both no association and also a protective effect from treatments," Monuteaux said. "But those studies had some methodological limitations, and not all of them followed their samples well into late adolescence and early adulthood."

The Massachusetts General Hospital investigators designed their study to overcome the shortcomings of previous studies. They followed their research subjects up to a median age of about 22, included an assessment for psychiatric problems such as conduct disorder that are associated with substance abuse, and applied rigorous methods to accurately analyze data.

The research study team interviewed 112 young men (ranging in age from 16 to 27) a decade after they had been diagnosed with ADHD about their use of alcohol, tobacco and a variety of psychoactive drugs. Seventy-three percent of the subjects had been treated with stimulants at some time, and 22 percent were currently taking the stimulant medications.

The study found no relationship between having ever received stimulant treatment and the risk of future alcohol or other substance abuse. The age at which stimulant treatment began and how long it continued also had no impact on substance use.

"This study is a continuing effort to explicate the factors that mediate risk. It is methodologically sound and suggests that, as always, things are more complicated than we want them to be. The study demonstrates that the use psychostimulants for ADHD children do not increase the risk for substance abuse in adulthood, but it also suggests there is no protective effect, said Dr. Jon A. Shaw, director of the Division of Child and Adolescent Psychiatry and Behavioral Science at the University of Miami.

Symptoms of ADHD include impulsiveness, hyperactivity and inattention. According to a study published last fall in the Archives of Pediatrics & Adolescent Medicine, almost 9 percent of American children have ADHD, but only 32 percent of them are getting the medication they need.

"There is sufficient evidence that parents should be reassured that the use of psychostimulant medication for the treatment of ADHD in children and adolescents does not increase the risk for substance abuse in later life and remains the most effective treatment for this condition," Shaw said.

More information

For more on ADHD, visit the National Institute for Mental Health.

MONDAY, Nov. 12 (HealthDay News) -- While some regions of the brain mature a few years late in youngsters with attention deficit hyperactivity disorder (ADHD), their brains do develop in a normal pattern, concludes a study by researchers at the U.S. National Institute of Mental Health (NIMH).

They found that the delay in brain maturation in children with ADHD was most prominent in regions at the front of the brain's outer mantle (cortex), which is involved in thinking, planning and attention.

Magnetic resonance imaging (MRI) scans of the brains of 223 children with ADHD revealed that half of 40,000 cortex sites attained peak thickness at an average age of 10.5, compared to age 7.5 in a group of children without ADHD.

However, both youngsters with ADHD and those without the disorder showed a similar back-to-front progression of brain maturation with different regions peaking in thickness at different times.

"Finding a normal pattern of cortex maturation, albeit delayed, in children with ADHD should be reassuring to families and could help to explain why many youth eventually seem to grow out of the disorder," research team leader Dr. Philip Shaw, of the NIHM Child Psychiatry Branch, said in a prepared statement.

The study was published this week in the online edition of the journal Proceedings of the National Academy of Sciences.

These findings support the theory that ADHD is caused by a delay in cortex maturation, the researchers said. They plan to investigate the genetic roots of this delay and methods of promoting recovery from ADHD.

More information

The Nemours Foundation has more about ADHD.