Gene Therapy for Psychiatry?

Gene therapy has taken a considerable time to get off the ground and find real practical usage for brain disorders. A lot of the problems with gene therapy have been due to the difficulty of introducing genes into the cell nucleus without causing cancer or an immune system response. After many years of failure, researchers are finally having some success with gene therapy. I mentioned previously that scientists have used gene therapy for Parkinson's patients with some resolution for specific symptoms.

There is a significant difference, though, between Parkinson's disease and psychiatric illnesses. Even though Parkinson's disease is a relatively complex disorder, the causes are much better understood by scientists than the causes of mental illnesses such as schizophrenia and depression. The low serotonin explanation for depression is bandied about a lot, but it is clearly an oversimplification. Mental illness cannot easily be explained by a simple neurotransmitter/receptor excess or deficiency. A lot of different neurotransmitters/receptors impact a person's mood and they often interact in numerous ways. Sometimes increasing a neurotransmitter/receptor in one area of the brain can improve mood while increasing it in another area it may make depression worse.

This brings up the problem with gene therapy. It would be very difficult to know what gene to add to improve specific mental illness symptoms and also what area of the brain to target. Gene therapy does have the potential to be extraordinarily precise as opposed to drugs which are largely blunt instruments. You could potentially increase a single receptor protein in a key area associated with mood. However, with increasing selectivity comes relatively less efficacy and difficulty in distinguishing true response from a placebo.

This recent article discusses the potential of gene therapy for psychiatry. The article mainly talks about gene therapy for drug abuse, something which I have previously discussed.

"Moreover, our research has identified a transcription factor, nuclear factor kappa B (NFkB), which mediates this structural change. Importantly inhibition of NFkB signaling through the use of viral gene therapy techniques with an inhibitor of kappa B kinase blocks NFkB signaling and the rewarding effects of cocaine in animals."

While this sounds like it might be possible to do in theory, addiction is an extremely complex disorder at the molecular level. There is a question of practicality for an intervention like this. Do you really expect drug addicts to undergo risky brain surgery to get gene therapy so they'll never find taking drugs rewarding again? Yeah, I'm sure drug addicts will just be lining up to undergo this procedure to make sure they'll never get a pleasure jolt from drugs. This therapy wouldn't necessarily increase an addict's normal capacity for pleasure, so I question the value of a treatment like this.

An older, overly optimistic article written in 2001 entitled "Gene Therapy for Mental Illness: Just Around the Corner?" also talks about the potential for this new treatment.

"Although gene therapy is in the earliest stages of development, it may still offer some benefits to psychiatry within the next five to 15 years, a scientist working in the field presages.

It's currently mid 2008 and I'm not aware of any gene therapy trials for mental illness in the pipeline. So this assessment seems unlikely to happen within the given time frame. The US appears to be moving towards more government control of the health care industry. This will likely lead to reduced innovation as companies will no longer have the financial incentives to take large risks. This would make it even less cost effective to run a clinical trial. Already, I think trying to perform a gene therapy trial for mental illness would be a logistical nightmare. The placebo effect alone would make success nearly impossible. So performing gene therapy for psychiatry has many barriers at both the molecular and societal level that may be difficult to circumvent. I am not confident that we will be seeing gene therapy in widespread use for psychiatric illness. Hopefully I'm being overly pessimistic.