by Eric Schuman
Photo by by Ptit@l
Research has shown that ADHD (Attention deficit / hyperactivity disorder) is strongly influenced by genes. It seems as if it is related to a problem within the dopamine reward system of the brain. Difficulties with this system could be the reason that people with ADHD and ADD (attention deficit disorder) seem to have trouble staying focused.
The bad side of ADHD is pretty obvious: It makes people seem unfocused, hyperactive. But new research proposes that it has benefits. Why else would the genes associated with ADHD still be in the gene pool? Researchers Dan Eisenberg of Northwestern University and Ben Campbell of the University of Wisconson, Milwakee, think they have an answer. In a study published in BMC Evolutionary Biology, they posit that the sort of activities associated with ADHD—a want of novelty, behavioral flexibility, being hyper-aware in environments—were in fact advantageous to nomadic herdsman. They go on to link ADHD to obesity. In the modern world where a scarcity of food (for many but clearly not all) no longer exists, dis-inhibition of seeking pleasure from things like food become exaggerated, leading to obesity. Many children with ADHD have higher BMI’s (body mass index) than their peers, before they go on medications that often lead to weight loss, they point out.
Campbell, Eisenberg and their collegues (2008) studied a tribe in Kenya. One half had stayed nomadic, and the other had become agricultural. They explain that within a nomadic context, the ADHD genes are beneficiary. When in a more sedentary context, those same genes result in increased weight and malnutrition. This allele that contains these genes is, of course, connected with ADHD. Therefore, it seems ADHD is both positive and negative. (more…)
by Stacy Locke
Psychologists have long been trying to unravel the mystery of schizophrenia. A recent study has found rare genetic variations in Schizophrenic patients that were previously undetected, which could point us in the right direction to understanding why and how a person develops schizophrenia.
The New York Times Science section reveals the new analysis, originally published in the journal Science. The researchers detected rare and unknown genetic mutations that occur three to four times more often in Schizophrenics than others. This collaboration involved the National Institute of Mental Health, The University of Washington, Seattle, and Cold Spring Harbor Laboratory. Blood samples were analyzed from 150 Schizophrenics and 268 people with no psychiatric disorders, using a new high-resolution technique. 53 of these mutations were found overall, showing not only a tendency in Schizophrenics, but also in a specific sub-group that developed the disorder in childhood. This discovery could point to an even more complex underlying genetic reason for the disorder than was previously believed.
This new study could indicate a new direction in Schizophrenia research, but even the senior author Jonathan Sebat admits that there is a long way to go and the findings could mean very little in the grand scheme of things. The most important thing to be taken from this study is that it provides evidence that the new high-resolution scanning technique can be successfully used to find minor genetic variations. “The take-home message is that there’s a new way to search for genetic links, and this new method goes straight to the underlying biology,” stated Sebat. This means it could help with understanding many disorders, not just schizophrenia.
Carey, B. (2006, March 25). Study Ties Genetic Variations to Schizophrenia. New York Times.
by Kelly Long
In a world where illnesses once thought debilitating have become more treatable than ever, the question of whether or not a treatment is available for an affliction like depression has become almost obsolete. The difficulty has shifted to the issue of which drug is best for which patient, and how a balance may be found between treatment and side effects.
Recent government-funded studies, reported in the New York Times, have shown that Celexa, an anti-depressant drug belonging to the class of selective serotonin reuptake inhibitors (SSRIs) may cause patients to experience suicidal thoughts. Interestingly, those same suicidal thoughts tended to be found in patients who did not actually attempt suicide, while it has been noted that the one patient in the study that did actually attempt suicide vehemently denied any thoughts of suicide.
Unsurprisingly, the physiology of the connection may be traced to the brain. Throughout the course of the study, two out of the sixty-eight genetic markers studied were noteworthy, as 36 percent of the subjects in possession of the markers experienced suicidal thoughts after taking Celexa. The markers coded for an amino acid called glutamate, which, aside from working as a natural antidepressant by activating neurons, is involved with learning and memory in the brain. Although the results of the tests were inconclusive, they raise the serious question of how treatment can be achieved without a flurry of undesirable (and sometimes dangerous) side effects. It is also remarkable to think that, with time and more research, a genetic test may be developed that is capable of pinpointing exactly which depression treatment is best for each patient.
[Editor's note: Interested readers may also want to look at this post about why the added caution around SSRIs also causes problems.]
Carey, Benedict. (2007 September 28). Genes Tied to Bad Reactions to Antidepressant Drug. New York Times. Retrieved September 30, 2007, from http://www.nytimes.com.