Advances Toward Personalized Psychiatry

The Diagnostic and Statistical Manual of Mental Disorders (DSM), currently in its fifth version, outlines the diagnostic criteria for mental illnesses. In the United States, it is commonplace to ascribe biological dysfunctions as the cause of mental illness, and therefore, assume medical treatment is the only viable solution. However, one might be surprised to discover how much is unknown in the field of psychiatry. A letter from the National Institute of Mental Health released on April 29th, 2013 states that “Unlike our definitions of ischemic heart disease, lymphoma, or AIDS, the DSM diagnoses are based on a consensus about clusters of clinical symptoms, not any objective laboratory measure.” The manual is created by a group of psychiatric professionals who debate what disorders should be defined, and what criteria the manual should establish for each illness. They, like everyone, are influenced by the culture and social climate they live in. This has led to the inclusion, and subsequent removal of, among other things, homosexuality and self-defeating personality disorder (which was given to women who were the victims of domestic violence and remained in the relationship) from the DSM.

The categories of the DSM define discrete clusters of symptoms; yet this doesn’t indicate that each disorder is the discrete consequence of a biological abnormality. Someone’s personality, immediate environment, and culture at large influence how someone expresses distress. A single, biologically derived disorder could be comprised of several DSM disorders. Conversely, a single disorder in the DSM, such as Major Depressive Disorder, colloquially referred to as depression, most likely comprises several disorders as defined by primary cause and response to treatments. In general medical practice, for example, if one thinks about the symptom of a sneeze, this could have several possible causes: inhaling pepper, allergies, or the common cold. While Benadryl might work for one of these cases, it would not be effective in the other two circumstances. Mental disorders, being more complex than a sneeze, are most likely due to varying degrees of genetic predisposition, environmental factors, and life circumstances. Only considering one factor grossly simplifies a very complex question.

There are several classes of medications for the treatment of psychiatric disorders, from selective serotonin reuptake inhibitors (SSRIs), to monoamine oxidase inhibitors (MAOIs), atypical and typical antipsychotics, lithium, and even selective serotonin reuptake excitors (SSREs) that work in the exact opposite manner of SSRIs. These medication classes are used as treatment options to treat a range of symptoms associated with mental illnesses. This means that there is not a single treatment for depression, bipolar disorder, or schizophrenia. Consumers may be surprised to learn that finding the right psychiatric medication involves a great deal of trial and error. Psychiatrists pick a medication or medications based on someone’s reported symptoms to initially try, and if their patient cannot tolerate the treatment at various doses, they try a different kind, until they identify one that is tolerable and shows some efficacy. As a result, patients who choose to seek a pharmaceutical treatment, are subject a guess-and-check method that relies heavily on luck. Throughout the process, they will likely endure a myriad of unpleasant to nearly intolerable side effects.

So, the question then becomes, how does someone get luck on their side? One possible option is seeking genetic testing for psychiatric drugs. The test works similarly to any other genetic testing, like 23andMe. Genetic tests look at several specific genes and identify which genetic variants someone has.

Having previously analyzed the most likely trait to occur in a population with a certain genetic variant, the test can predict that someone carrying this variant is more likely to possess that trait. For instance, 23andMe results will indicate if someone is likely to have a given trait, such being able to roll their tongue. Given the complexity of factors that go into trait selection and presentation, the results are not a guarantee. Someone may be more likely to be able to roll their tongue, but this does not indicate whether, or not, they can.

In psychiatric genetic testing, the results indicate, among other variables, likely metabolic rates for different medications. Metabolic rates indicate how long it takes for the body to process and eliminate various medications, and therefore which medications are likely to cause more palpable side effects. The results list the brand names of numerous psychotropic drugs and someone’s likely respective metabolic processing rates. While the results are not guaranteed to be accurate, by having a psychiatrist choose medications that are less likely to cause severe side effects, the odds of selecting more tolerable medications is increased. However, this test doesn’t necessarily indicate which medications are likely to be most effective in treatment. The Food and Drug Administration has released a warning that genetic tests have the potential to steer patients toward ineffective medications. While genetic testing isn’t guaranteed to identify the perfect pharmaceutical treatment for a mental illness, it does increase the odds of trying medications with tolerable side effects.

GeneSight, one brand of genetic test for psychiatric drugs, costs $2,000 out of pocket. While it is not covered by all insurance companies, several insurers do cover a significant portion of the cost. Myriad, the company that creates GeneSight, reports that 95% of patients spend less than $330 to get tested.

Psychiatry is far from a perfect science, nor is pharmaceutical treatment the only viable option. Scientists are currently working to develop tests assessing the efficacy of drugs for individual patients. For example, a recent study has found evidence for correlating EEG data taken prior to medication intervention, and therapeutic response to Prozac. As the public waits for more tests to be available to aid in the selection of effective pharmaceutical treatments, for those who are financially able, it may be worth it to leverage luck onto their side.rning, and keep believing in the version of yourself you’re becoming.