Cracking the brain’s genetic code pg. 4
On the other hand, the proposed merger of the National Institute of Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism is a positive sign. Genetic studies are revealing risk genes common to different types of substance abuse, and including problems with gambling. Furthermore, serious mental illnesses such as schizophrenia and bipolar disorder have a high prevalence of co-occurring substance abuse that adversely affects outcome. Anything we can do to increase the cross talk among these three institutes, the NIDA, NIAAA and NIMH, should be beneficial for developing more effective treatments.
Is it more difficult to develop drugs for children and adolescents?
Scolnick: Developing drugs for use in children is harder. Significantly more safety data are required. Characteristically any trials with a new medicine are started in children only after almost all of the animal safety is done, including carcinogenicity studies, and after significant information is available in adults on efficacy and safety. And then you have to start again to find the right dose (in children and adolescents), because the dose that you find in adults may or may not be the right dose based on the size of the younger people plus their metabolic state. It’s significantly more work to do that.
Are there concerns in treating children with these kinds of drugs, considering that their brains are still developing?
Coyle: Yes, and it cuts two ways. Up until about 15 years ago, because of the dominance of psychoanalytic thinking in the field, it was believed that children could not have depression. Unfortunately, children not only can have depression, they can commit suicide, suicide being the third most common cause of death in adolescents. Studies done characterizing depression in children have shown that at any point in time about 1-2% of children under the age of puberty would satisfy the diagnosis of major depressive disorder.
When depressed children were followed longitudinally, it turned out that they would spend somewhere around 70% of their time in a state of depression or minor depression, so when you think about the impact of being psychologically depressed, feeling bad about yourself, feeling pessimistic, perhaps feeling suicidal, from say the age of 8 until the age of 15, that’s half one’s life. So there’s clear evidence that not treating can markedly distort the developmental trajectory.
So, as I say, it cuts two ways. Yes, there is a very real concern that these drugs, which affect how neurons communicate with each other in the brain, could have some adverse effects on brain development. That is currently a topic of investigation and research supported by the National Institute of Mental Health. On the other hand, not intervening can result in a child with a condition being persistently symptomatic and having a very skewed developmental trajectory.
By studying genes that affect drug metabolism, scientists are beginning to understand better why certain individuals respond differently to medications. Will this field of study, called pharmacogenomics, contribute to a new era of “individualized medicine,” the tailoring of medical treatment to individuals with psychiatric disorders?
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