Just Over Half of Americans Diagnosed with Major Depression Receive Care

More Receive Psychotherapy than Medication; Study Provides New Detail on Disparities
Overall, only about half of Americans diagnosed with major depression in a given year receive treatment for it, and even fewer—about one fifth—receive treatment consistent with current practice guidelines, according to data from nationally representative surveys supported by NIMH. Among the ethnic/racial groups surveyed, African Americans and Mexican Americans had the lowest rates of use of depression care; all groups reported higher use of past-year psychotherapy vs. medication for depression. MFT Continuing Education
Background
Depression is a leading cause of disability in the United States. Past research has found that many people with depression never received treatment, and that the percentage of those receiving treatment varies with ethnicity and race. In order to provide comprehensive and up-to-date information on depression care, with a particular emphasis on minority groups, NIMH's Collaborative Psychiatric Epidemiology Surveys initiative (CPES) has combined data from three nationally representative studies: the National Survey of American Life, the National Comorbidity Survey-Replication, and the National Latino and Asian American Study.

This Study
Scientists at Wayne State University, Detroit, MI; the University of Michigan, Ann Arbor; the University of California, Los Angeles; and the Harvard School of Public Health, Boston, MA, carried out the current study, which reports on data from CPES collected between February 2001 and November 2003 from 15,762 residents 18 years and older. The size of the sample makes it possible to examine health care use in ethnic/racial groups with a new level of detail, distinguishing between groups often surveyed as one population. The investigators were able to break out types of care used, and to assess to what extent the care used was consistent with the American Psychiatric Association (APA) Practice Guidelines for the Treatment of Patients with Major Depressive Disorder. Finally, they examined how factors enabling healthcare access—insurance, education, and household income—influenced rates of care.

A central finding was that overall, 51 percent of all those in the study who met criteria for major depression during the prior year received some kind of treatment for it, with only 21 percent receiving care that was consistent with the APA Guidelines.

Other key study findings addressed disparities, types and quality of care received, and factors that enable access to healthcare.

Prevalence and severity of major depression was similar among the five studied ethnic/racial groups—Mexican Americans, Puerto Ricans, Caribbean Blacks, African Americans, and non-Latino Whites. However, African Americans and Mexican Americans were least likely to receive any care or care consistent with practice guidelines. Compared with non-Latino Whites for example, of whom 54 percent with depression received care, 40 percent of African Americans and 34 percent of Mexican Americans did. The rate of care for Puerto Ricans was close to that of Whites, 50 percent.
Across these population groups, psychotherapy was used more frequently than medications (pharmacotherapy). Overall, 34 percent received pharmacotherapy; 45 percent psychotherapy. Psychotherapy was more likely to be consistent with APA guidelines than pharmacotherapy, suggesting that adherence—the extent to which patients completed the recommended therapy—was greater for psychotherapy than pharmacotherapy. The contrast between the rates of Guideline-consistent psychotherapy and pharmacotherapy use was greatest among Caribbean Blacks, African Americans, and Mexican Americans.
Puerto Ricans had rates of treatment use, and treatment that was consistent with care guidelines, that were similar to, or higher than, non-Latino Whites.
Differences in factors enabling healthcare access appeared to contribute substantially to disparities in mental healthcare use, particularly for Mexican Americans. When differences in these enabling factors were controlled for statistically—so in effect, the population groups being compared had the same rates of enabling factors—the degree of disparities in use of care by Mexican Americans was reduced. For Caribbean Blacks and African Americans, statistical control of enabling factors reduced disparities in psychotherapy use, but not use of pharmacotherapy.
Health insurance coverage was associated with a greater likelihood of depression care, but not guideline consistent care. The pattern with education was reversed: education was associated with a greater likelihood of care that was consistent with the APA Guidelines, but not with greater use of care in general.
Significance
This study, with its large sample size and emphasis on minority groups, provides a more nuanced and detailed picture of the care received for major depression among different ethnic/racial groups and of factors that contribute to disparities. Lead author Hector González at Wayne State University said that Mexican-Americans make up over two-thirds of Latinos in the U.S.: "We found in our study that there are some really distinctive differences in mental healthcare use between Mexican Americans and other Latino subgroups that have not been previously reported." Estimates suggest that Latinos will make up close to one-third of the U.S. population by mid-century; the study findings suggest that Mexican Americans should be a focus of efforts to reduce health disparities to ensure the nation's health in coming decades.

All groups were more likely to have received psychotherapy than pharmacotherapy. Caribbean Blacks and African Americans were particularly unlikely to receive pharmacotherapy consistent with APA guidelines; enabling factors such as education, health insurance, and income did not explain the lower rates of medication use. The authors note possible reasons for this, including research indicating that perceived discrimination can shape health care seeking. They speculate that the non-immigrant status of Puerto Ricans—and with that, greater predominance of English language use within this group—may be factors in their relatively high rates of health care use.

Findings from this study will inform future research on adherence to various depression therapies, and the factors that shape differences in care among racial/ethnic groups. "Future studies," say the authors, "should explore the extent to which patients' subjective experiences of racial bias may affect their access and utilization of mental healthcare."

Reference
González, H.M., Vega, W.A., Williams, D.R., Tarraf, W., West, B.T., and Neighbors, H.W. Archives of General Psychiatry 2010;67(1):37-46.

Novel Model of Depression from Social Defeat Shows Restorative Power of Exercise

In a study in a mouse model that mimics the contribution of social stress to human depression, an environment that promotes exercise and exploration alleviated depressive behavior in the mice. The beneficial effect of activity depended on the growth of new neurons in the adult brain. Continuing education for counselors
Background
In the 1990s scientists established that new neurons grow in the adult as well as the immature brain. The functions of neurogenesis, or new neuronal growth, are still being explored, but it is known that stress slows this growth in the hippocampus―a brain center involved in the formation of new memories―and that antidepressant treatment promotes it.

Previous research in animal models has also demonstrated that environmental enrichment―the addition of features in an animal's cage that provide opportunities for exercise and investigation―fosters resilience to stress and can alleviate the depression-like behavior that results from uncontrollable stress. Environmental enrichment has also been shown to promote hippocampal neurogenesis in animals.

This Study
This work, by Michael Lehmann and Robert Schloesser and colleagues in NIMH's intramural research program, focused on the ability of environmental enrichment to reverse depressive behaviors caused by social defeat, a situation paralleling the social stresses that can trigger human depression. Past work in animal models has often used physical stressors such as electric shock, restraint, or forced exercise to create depressive behaviors. In addition, the scientists inserted a gene in mice that made it possible to selectively interrupt the growth of new neurons at a specific time and in a specific population of cells in the hippocampus, avoiding any spillover effects to other tissues.

More on Mouse Behavior
Although "dominant and aggressive" may not sound like descriptors that apply to mice, male mice in the wild live apart from other males and they are intensely aggressive if housed together. In this study, male mice were allowed to interact directly for no more than five minutes at a time and were supervised to make sure one mouse did not injure or kill the other.

Mice naturally cover territory in the wild; if furnished with running wheels in a cage, they will, on their own, run the equivalent of as much as 6 to 10 kilometers in one day.
Stress―in this case social defeat stress―has unmistakable effects on the behavior of mice. Researchers use a variety of tests to describe changes in behavioral tendencies, including observing how boldly the mice explore an unfamiliar cage; how much time they will choose to spend in a dark (safe) vs. light (risky) compartment; and the extent to which they'll indulge their taste for something pleasant like sweetened water. Mice who have been the losers of repeated social defeats are visibly cautious and subdued, even in the judgment of observers who do not know whether they were winners or losers in a conflict.

Test mice in this study were housed across a partition in the home cage of a dominant, aggressor mouse. For 5 minutes per day, the partition was removed, allowing the "intruder" and dominant mouse to interact directly. After 2 weeks, the test mice consistently behaved submissively. The test mice were then divided and placed in either a spare environment, or one enriched with running wheels, and tubes of various shapes and sizes. Some of the mice assigned to either environment were a standard laboratory strain. Others had an inserted gene targeted to a population of hippocampal cells that give rise to new neurons; in mice with this transgene, the antibiotic valganciclovir is toxic to dividing cells so neurogenesis is prevented when the drug was added to the animals' feed.

The nontransgenic test mice in the enriched environment, but not those in the more spartan cages, recovered from the submissive behavior seen after social defeat. The transgenic mice, in which neurogenesis was stopped, remained submissive, resembling the mice housed in the impoverished environment.

In tests to probe affect, or mood, the transgenic mice housed in the enriched environment also resembled mice housed in the impoverished environment in that they showed the same reduced inclination to explore, greater anxiety, and a less than normal interest in sweet solutions which mice usually prefer. Interruption of neurogenesis had no effects on the baseline health and behavior of the animals, so the lack of new neurons did not cause depression, but interfered with recovery.

Significance
This study demonstrates that psychosocial stress in mice can cause behavior resembling human depression, which environmental enrichment can ameliorate as long as neurogenesis is intact.

Key elements of this study included its use of a social stressor, more analogous to the social experiences that can contribute to human depression than the physical stressors often used in research. In addition, the use of the transgene in test animals enabled the scientists to control the interruption of neurogenesis with precision with respect to both timing and location and with no effects on neighboring cells.

According to author Michael Lehmann, "There are multiple avenues through which environmental enrichment can have a positive impact on depression. In this model we use a natural psychosocial stressor with relevance to social stress in humans, to induce depressive-like behaviors. We show that environmental enrichment can facilitate the recovery from social stress, and that adult neurogenesis is a requirement for the rehabilitating effects of enrichment."

The authors suggest that neurogenesis may be central to the ability of an animal to update emotional information upon exposure to a novel environment. With neurogenesis impaired, they may be unable to integrate information on the features of a new, changed environment. The resulting cognitive distortions may trigger symptoms of major depression.

Research suggests that one important consequence of environmental enrichment is its impact on the function of the body's stress response system. Animals in these enriched environments show positive effects on the physiology of stress resilience. In humans, successful antidepressant treatment is reflected in similar beneficial changes. Prior research has also linked neurogenesis with positive changes in the stress response system.

The authors also point out that in humans, physical exercise and positive psychosocial activity have beneficial effects on depression and stress resilience. Forms of entertainment that encourage mental activity, according to Lehmann, such as reading, video games, exercise and outdoor recreation could have longer lasting changes for many suffering from mild depressive symptoms than pharmacologic treatment, without the accompanying side effects.

Reference
Schloesser, R.J., Lehmann, M., Martinowich, K., Manji, H.K., and Herkenham, M. Environmental enrichment requires adult neurogenesis to facilitate recovery from psychosocial stress. Molecular Psychiatry 2010 Dec;15(12):1152-1163. Epub 2010 March 23.

From Neurons to Thought: Coherent Electrical Patterns Observed Across the Brain

Amidst the background hum of electrical signaling generated by neurons in the brain, scientists have found that local groups of neurons, firing in coordination, sometimes create a signal that is mirrored instantaneously and precisely by other groups of neurons across the brain. These transient episodes of coherence across different parts of the brain may be an electrical signature of thought and actions. MFT CEUs
Background
One of the goals of neuroscience research is to identify how thoughts and actions are encoded in the activity of neurons. A challenge has been to extract meaningful patterns from the ongoing tumult of electrical activity in the brain. This global electrical activity is built from the firing of individual neurons. A single neuron responds to a stimulus in an all or nothing manner—if the stimulus reaches a certain threshold, the neuron “fires” an electrical signal. Groups of neurons firing in a coordinated way create a local electrical field that is in itself a signal that can vary in pattern. These local field potentials (LFPs) have been a target of research.

This Study
In this research, Dietmar Plenz and colleagues at NIMH and Duke University pinpointed LFPs in the cortex that surpassed a minimal size threshold, and then searched the rest of the cortex to see what was occurring at the same time. In each case, they found other answering LFPs across the brain that mimicked each other with high precision: there was no degradation or loss of power (amplitude) in the signal. Unlike what is observed after dropping a stone in a pond—with wavelets getting smaller farther from the stone—the intensity of the LFPs was the same across the brain. The investigators call these LFPs coherence potentials. Although LFPs that occur during these transient episodes of coherence are identical to each other, they are also multidimensional and potentially infinitely diverse, providing a means to encode information. Most LFPs do not reach the threshold that characterizes a coherence potential but with those that do, propagation of the LFPs across the brain is extraordinarily rapid. The authors note that the rapid dispersion of such a signal mimics the spread of ideas and behaviors in social networks; a sufficiently provocative idea can spread very swiftly through a population.

Significance
Coherence potentials simultaneously engage groups of neurons in different parts of the brain with diverse functions. This is consistent with the multi-faceted nature of mental associations and memories—a memory focused on a person or object might conjure various kinds of sensations and thoughts—visual, tactile, auditory, and emotional, for example.

These findings emerged from recent work that demonstrated that, like other systems in nature, the cortex exists at a critical state between stability and instability. A characteristic of this state in the brain is the presence of neuronal avalanches—if a stimulus reaches a certain threshold, it will set off cascades of neuronal firing. This dynamic is analogous to when the slope of a sandpile reaches a point at which adding one more grain will trigger an avalanche. The adherence of the cortex to this critical state ensures that the brain can respond to a wide range of stimuli, but not lapse into a chaos of excess activity (such as the too-synchronous firing during epilepsy). Coherence potentials emerge predominantly when the cortex is critical, that is, when it displays neuronal avalanches. Nudging the cortex away from this point, by inhibiting neuronal signaling with medications for example, disrupts these dynamical patterns.

What’s Next
Coherence potentials were present in cells in culture as well as awake monkeys, a robust demonstration that they occur in the functioning cortex. Future studies will be aimed at monitoring coherence potentials in the context of behavioral function with the ultimate aim of making a connection between specific coherence potentials and behaviors.

Reference
Thiagarajan, T.C., Lebedev, M.A., Nicolelis, M.A., and Plenz, D. Coherence potentials: loss-less, all-or-none network events in the cortex. PLoS Biology 2010, doi:10.1371/journal.pbio.1000278.

Effects on Personality May Be Mechanism of Antidepressant Effectiveness

Results of a study of antidepressant treatment for major depression suggest that changes in personality traits seen in patients taking the drug paroxetine (Paxil) may not be the result of the medication’s lifting of mood but may instead be a direct effect of this class of drugs and part of the mechanism by which they relieve depression. MFT Continuing Education
Background
People with a high level of the personality trait neuroticism—characterized by a tendency to experience negative emotions and moodiness—are more likely than others to develop depression. Neuroticism is one of five personality traits that psychologists use as an organizing scheme for understanding personality: the other four traits are extraversion, openness, conscientiousness, and agreeableness. People who take anti-depressants report lower levels of neuroticism and increased extroversion, in addition to a lifting of depression. The assumption has been that these changes in personality measures were the result, not the cause, of a lifting of depression.

Studies in twins suggest that to a large degree the same genetic factors underlie both neuroticism and depression risk. Research also suggests that the neurotransmitter serotonin plays a role in the expression of both neuroticism and extraversion. The class of anti-depressant drugs to which paroxetine belongs—the selective serotonin reuptake inhibitors (SSRIs)—increase the neurotransmitter’s availability in the brain.

This Study
To test the relationship between SSRIs and personality, investigator Tony Tang and colleagues at Northwestern University, Evanston, IL, the University of Pennsylvania in Philadelphia, and Vanderbilt University in Nashville, TN, randomly assigned patients with major depressive disorder (MDD) to receive paroxetine (120 patients), placebo (60 patients), or cognitive therapy (60 patients).

After 8 weeks, medication and cognitive therapy (CT) each proved more effective than placebo in reducing depression. In addition, measures of neuroticism (based on standard surveys) in the groups receiving medication or cognitive therapy dropped, while extraversion scores rose. The changes were striking; while patients receiving placebo also reported small changes in both traits, the changes in patients on paroxetine were four to eight times as large. Patients receiving paroxetine had much greater changes in personality traits than patients receiving placebo even when the degree of improvement in depression was the same. This suggested that the effects on personality traits were not the result of the drug’s lifting of depression. After accounting for decreases in depression in patients receiving CT, the improvement in extraversion, but not neuroticism, remained significant.

In further comparison of paroxetine with placebo, patients who had initially taken placebo were given the option after 8 weeks to take paroxetine. During the placebo phase, there were small changes in neuroticism and extraversion; much greater changes occurred after 8 weeks on paroxetine. Finally, those patients on paroxetine with the greatest degree of change in neuroticism (but not extraversion) were least likely to relapse to depression; the degree of changes in personality in those receiving CT did not affect the chances of relapse.

Significance
While the neurochemical effects of SSRIs are known, how those changes act to reduce depression is not clear. These results contradict the prevailing assumption that changes seen in personality traits in patients taking SSRIs are a result of the drugs’ effects on depression. SSRIs may alter personality directly—and thus lift depression—or may act on a third factor that underlies both. CT may alter personality by a different path. Continued research on how these treatments work can provide a clearer understanding of the mechanism of action of SSRIs and how treatment can be best used to reduce depression and minimize relapse.

Reference
Tang, T.Z., DeRubeis, R.J., Hollon, S.D., Amsterdam, J., Shelton, R., and Schalet, B. Personality change during depression treatment. Archives of General Psychiatry 2009 Dec;66(12):1322-30.

Symptoms of Bipolar Disorder May Go Undiagnosed in Some Adults with Major Depression

Nearly 40 percent of people with major depression may also have subthreshold hypomania, a form of mania that does not fully meet current diagnostic criteria for bipolar disorder, according to a new NIMH-funded study. The study was published online ahead of print August 15, 2010, in the American Journal of Psychiatry. LPC CEUs
Background
Mania is a symptom of bipolar disorder. According to the Diagnostic and Statistical Manual for Mental Disorders (DSM-IV), it is generally defined as a discrete period of increased energy, activity, euphoria or irritability that leads to marked impairment in one’s daily life. The DSM-IV states that a manic episode lasts for one week or more, and may sometimes require hospitalization. Hypomania is defined as a milder form of mania that lasts for four days at a time, but does not interfere with one’s daily activities. The majority of people diagnosed with bipolar disorder experience repeated episodes of hypomania rather than mania.

For this new study, Kathleen Merikangas, PhD., of NIMH, and colleagues aimed to characterize the full spectrum of mania by identifying hypomanic episodes that last less than four days among those diagnosed with major depression. They described this type of hypomania as subthreshold hypomania. Merikangas and colleagues used data from 5,692 respondents of the National Comorbidity Survey Replication (NCS-R), a nationally representative survey of American adults ages 18 and older.

Results of the Study
The researchers found that nearly 40 percent of those identified as having major depression also had symptoms of subthreshold hypomania. Compared to those with major depression alone, those with depression plus subthreshold hypomania tended to be younger at age of onset and to have had more coexisting health problems, more episodes of depression and more suicide attempts. They also found that among those with subthreshold hypomania, a family history of mania was just as common as it was among people with bipolar disorder.

Significance
According to the researchers, the findings indicate that many adults with major depression may in fact have mild but clinically significant symptoms of bipolar disorder. In addition, because many with subthreshold hypomania had a family history of mania, the researchers suggest that subthreshold hypomania may be predictive of future hypomania or mania. Previous research has indicated that young people with subthreshold hypomania symptoms are more likely to develop bipolar disorder over time, compared to those without subthreshold hypomania, said the authors.

What’s Next
The researchers suggest that depression and mania may be defined as dimensions, rather than as discrete diagnostic categories. Clinicians should be aware that patients who report repeated episodes of subthreshold hypomania may have a risk of developing mania, the researcher concluded.

Reference
Angst J, Cui L, Swendsen J, Rothen S, Cravchik A, Kessler R, Merikangas K. Major depressive disorder with sub-threshold bipolarity in the National Comorbidity Survey Replication. American Journal of Psychiatry. Online ahead of print August 15, 2010.

National Survey Confirms that Youth are Disproportionately Affected by Mental Disorders

About 20 percent of U.S. youth during their lifetime are affected by some type of mental disorder to an extent that they have difficulty functioning, according to a new NIMH survey published in the October 2010 issue of the Journal of the American Academy of Child and Adolescent Psychiatry. The data support the observation from surveys of adults that mental disorders most commonly start in early life. CCS Continuing Education
Background
Many regional surveys conducted in the United States have indicated that about one in four to five children experience a mental disorder sometime in their life. But until now, no nationally representative surveys had been conducted to determine if these prevalence rates of a wide range of mental health problems hold true across the nation.

Kathleen Merikangas, Ph.D., of NIMH and colleagues analyzed data from the National Comorbidity Study-Adolescent Supplement (NCS-A), a nationally representative, face-to-face survey of more than 10,000 teens ages 13 to 18. They used standard diagnostic criteria set by the American Psychiatric Association's Diagnostic and Statistical Manual (DSM-IV) to determine lifetime prevalence of mental disorders among the teens. To follow up on the teens' responses, they also collected data via mailed questionnaires completed by one parent or guardian of each teen surveyed.

Results of the Study
Overall, nearly half of the sample reported having met diagnostic criteria for at least one disorder over a lifetime, and about 20 percent reported that they suffered from a mental disorder with symptoms severe enough to impair their daily lives. In addition,

11 percent reported being severely impaired by a mood disorder (e.g., depression or bipolar disorder),
10 percent reported being severely impaired by a behavior disorder such as attention deficit hyperactivity disorder or conduct disorder,
8 percent reported being severely impaired by at least one type of anxiety disorder.
In addition, about 40 percent of those who reported having a disorder also met criteria for having at least one additional disorder. Those with a mood disorder were more likely than others to report having a coexisting disorder. Underscoring the notion that mental disorders manifest early in life, the researchers also found that symptoms of anxiety disorders tended to emerge by age 6, behavior disorders by age 11, mood disorders by age 13, and substance use disorders by age 15.

The researchers also noted strong links between parental characteristics and their teen's disorders. For example, children of parents with less education (e.g., no college degree) were at an increased risk for having any kind of mental disorder. And compared to teens with married or cohabiting parents, those with divorced parents also were at higher risk for a disorder, especially anxiety, behavior and substance use disorders.

Significance
The NSC-A results provide a broader and longer-term outlook compared with last year's National Health and Nutrition Examination Survey (NHANES), which asked respondents about diagnosed disorders and service use within a 12-month window only, and was limited to six disorders.

According to the NCS-A researchers, the percentage of youth suffering from mental disorders is even higher than the most frequent major physical conditions in adolescence, including asthma or diabetes. The results reiterate the importance of developing prevention strategies and promoting early intervention for at-risk children and adolescents.

What's Next
More research is needed to better understand the risk factors for developing a mental disorder in youth, as well as how to predict which disorders may continue into adulthood. In addition, the researchers acknowledge the need for more prospective research to tease apart the complex interplay among socioeconomic, biological and genetic factors that may contribute to the development of mental disorders in youth.

Reference
Merikangas KR, He J, Burstein M, Swanson SA, Avenevoli S, Cui L, Benjet C, Georgiades K, Swendsen J. Lifetime prevalence of mental disorders in U.S. adolescents: Results from the National Comorbidity Study-Adolescent Supplement (NCS-A). Journal of the American Academy of Child and Adolescent Psychiatry. 2010 Oct. 49(10):980-989.

Attention woes in kids with Tourette syndrome likely caused by co-occurring ADHD

Co-occurring attention deficit hyperactivity disorder (ADHD) may be at the root of attention problems in children with Tourette syndrome (TS), according to NIMH-funded researchers. Their findings also support the theory that children with TS develop different patterns of brain activity in order to function at the same level as children without TS. The study was published in the November 2010 issue of the Journal of the American Academy of Child & Adolescent Psychiatry. LCSW Continuing Education
Background
Tourette syndrome is a chronic neurological disorder associated with repetitive, involuntary movements and vocalizations called tics. Many with TS also experience neurobehavioral problems such as inattention, hyperactivity, and impulsivity—symptoms that overlap with ADHD. In fact, researchers estimate that between 50-90 percent of youth with TS also have ADHD.

To explore the role of co-occurring ADHD in TS, Denis Sukhodolsky, Ph.D., of the Yale Child Study Center, and colleagues studied 236 children, of which:

56 had TS only
64 had ADHD only
45 had TS+ADHD
71 had neither and served as a comparison group.
The researchers used well-known, standardized measures to evaluate the children's performance on tasks requiring:

Sustained attention and inhibitory control—Participants were shown various letters on a computer screen and told to press a button when they saw certain letters but not press the button when they saw a non-target letter.
Cognitive inhibition—Participants were shown an array of dots on sheets of paper and asked to name their color (red, green, blue) as quickly as possible. In related tasks, participants were shown pages with similarly arrayed words ("red," "green," "blue") printed in black ink or a mismatched color of ink (such as "red" printed in green ink) and asked to read the words as quickly as possible.
Fine motor control—Participants placed small pegs in a specially designed pegboard in 30-second trials using only their dominant hand, only their non-dominant hand, and both hands at the same time.
Visual-motor integration—Participants copied 24 geometric designs, presented in order of increasing difficulty.
Results of the Study
Children with TS+ADHD showed similar problems with sustained attention as children with ADHD only. However, unlike those with ADHD only, children with TS+ADHD performed at the same level as the comparison group on all other tasks.

Children with TS only performed at the same level as the comparison group in tasks involving response inhibition and visual-motor integration. They performed at a slightly lower level than comparison children on the fine motor control task. Girls with TS only scored higher than boys with TS only on fine motor control tasks using their dominant hands.

Significance
The study helps to identify brain functions specific to particular disorders and the mechanisms underlying these functions.

Similarities in performance between children with TS+ADHD and those with ADHD only suggest that co-occurring ADHD may underlie attention problems in children who have TS, according to the researchers.

The researchers also noted that the children with TS only didn't show impairment in response inhibition, lending support to a theory that such children develop compensatory brain mechanisms in an effort to control involuntary tics. Past imaging studies have shown that, during tasks involving response inhibition, children with TS have greater than normal activity in brain areas associated with cognitive control.

Differences in fine motor skills between girls and boys with TS may indicate differing developmental pathways and patterns of brain growth between the sexes. Because problems with fine motor control in childhood are associated with more severe tics in adulthood, the researchers highlighted this finding as an area for further study.

What's Next
Future studies may help advance the understanding of how TS arises and changes in brain growth and functioning that are associated with the disorder.

Reference
Sukhodolsky DG, Landeros-Weisenberger A, Scahill L, Leckman JF, Schultz RT. Neuropsychological functioning in children with Tourette syndrome with and without attention-deficit/hyperactivity disorder. J Am Acad Child Adolesc Psychiatry. 2010 Nov;49(11):1155-64.