For each of us, HD develops in a unique way. Sometimes our loved ones retain their mental clarity for years. For others, behaviors develop that can seem to imprison them. These behaviors can manifest as rituals or obsessions and are a common product of Huntington’s. The resulting consequences of obsessive compulsive behaviors are familiar to any of us, caregiver, bystander or affected patient. Embarrassment, agitation, desperation, helplessness, all of these are common, frequent, emotions experienced by both caregiver and patient. Understanding how this behavior arises in the HD affected brain can provide some helpful insight for caregivers and relief for patients still cognitively aware of the behavior.
The National Institute of Mental Health (NIMH) characterizes Obsessive Compulsive Disorder as recurring thoughts (obsessions) that compel sufferers to repeatedly perform rituals (compulsions). The most common example that probably comes to mind is the germaphobe, a la Howie Mandel. However, less well known obsessions are still common, such as hoarding, frequent thoughts of violence or persistent thoughts of performing sexual acts (even, perhaps, acts the person dislikes). Research indicates that OCD individuals experience neurotransmitter dysregulation, specifically dopaminergic hyperfunction (over production of dopamine) and serotonergic hypofunction (decreased production of seratonin).
It is no coincidence then, that Huntington’s patients who also have this dopaminergic hyperfunction often exhibit OCD behaviors. Dopamine is a very busy neurotransmitter, sending signals related to reward-motivated behavior, motor function, and the release of several important hormones. In Huntington’s, the mutated Htt protein is particularly toxic to brain cells and its effects begin at the striatum. The striatum, among other responsibilities, balances motivation. Thus allowing one to accurately act on or inhibit a behavior in complex social situations. Further, the striatum is made up of metabotropic dopamine receptors. So understanding this center of the brain, we can see that the HD affected individuals’ striatum is assaulted on two fronts: toxicity and overproduction of dopamine.
This two pronged assault can be seen in both a reduction of inhibitions and an increase in compulsive behavior. Many HD affected individuals are unaware of the severity of their obsessions, particularly in the midst of the compulsive act. If it is a fear driven compulsion, often the patient is unable to determine if the fear is irrational. As cognitive function degenerates, the obsessive behaviors may change or increase in severity. Simple instruction may be ineffective at curbing the undesirable behaviors.
Behavioral therapy and cognitive behavioral therapy are considered the first-line treatments for OCD. A common method is called exposure and ritual prevention. In this approach, the patient is routinely exposed to the trigger and practices refraining from the ritual. For instance, repeated practice of throwing out the garbage may be an exercise for someone hoarding. A similar method called associative splitting can help the brain re-associate the trigger(s). For instance, if spiders trigger a fear driven compulsion, the therapy could involve trying to associate spiders with children’s books, elimination of flies, cartoon images, etc.
Each of these methods can prove more difficult to implement with the HD patient, as the primary dysfunction of the brain system is ongoing and, generally, increasing. Medication is often prescribed to accompany these behavioral treatments, with mixed results on their efficacy versus non medicated patients. Typically these medications include the anti-anxiety, anti-psychotic, and/or anti-depressant medications already commonly prescribed to HD patients. For particularly destructive or socially unacceptable compulsions, i.e. public masturbating, inappropriate sex talk, the best method may be to remove as many triggers as possible until the compulsion can be better prevented. It is important to find a physician who is willing to aggressively treat each element of the HD patient. Because research varies so greatly from one group to another, each patient’s treatment will have to be customized to the individual and have the flexibility to accommodate the patient’s evolving disorder.