Huntington's Disease and Addiction.
Is there a relationship?

It would be a modern day tragedy if pre-symptomatic Huntington's Disease sufferers were being lured into an addictive lifestyle through no fault of their own. I wonder what percentage of pre-symptomatic Huntington's Disease sufferers become drug addicts as compared to the general population. I wonder how many pre-symptomatic Huntington's Disease suffers never receive proper recognition of their condition or even die without Huntington's Disease ever being suspected of being implicated.

I'm in the very early stages of looking at this as a pure lay person with no medical training beyond basic First Aid. I do however have an enormous amount of hands on practical experience with drug addicts that has been gained over many years. It is those at risk of Huntington's Disease or who are suffering from it that interest me enormously. I am very concerned that there maybe pre-symptomatic Huntington's Disease sufferers who are leading miserable lives or worse still, are being incarcerated or dying as a result of drug related activities induced  by Huntington's Disease. I feel it is time to consider drug addicts at risk of Huntington's Disease as special cases when they come to notice for any drug related activity. Although they maybe deemed pre-symptomatic of Huntington's Disease, I seriously wonder if that is in fact true. Perhaps a drug abuse type syndrome exists that is attributable to very early stage Huntington's disease.

Pisani, A., P. Bonsi, et al. (2001). "Role of tonically-active neurons in the control of striatal function: cellular mechanisms and behavioral correlates." Prog Neuropsychopharmacol Biol Psychiatry 25(1): 211-30. Below is an extract from here.

1. The striatum is primarily involved in motor planning and motor learning. Human diseases involving its complex circuitry lead to movement disorders such as Parkinson's disease (PD) and Huntington's disease (HD). Moreover the striatum has been involved in processes linked to reward, cognition and drug addiction.
2. The high content of acetylcholine (ACh) found in the striatum is due to the presence of cholinergic interneurons. The intrinsic electrical and synaptic properties of these interneurons have been recently characterized. However, their functional significance is far from being fully elucidated.
3. In vivo electrophysiological experiments from behaving monkeys have identified these cholinergic interneurons as "Tonically Active Neurons" (TANs). They are activated by presentation of sensory stimuli of behavioral significance or linked to reward.
4. Experimental evidence showed that integrity of the nigrostriatal dopaminergic system is essential for TANs to express learned activity.
5. PD is known to be due to the loss of the nigrostriatal dopaminergic pathway and the ensuing imbalance between the content of dopamine and acetylcholine in the striatum. This evidence supports the hypothesis that cholinergic interneurons, or TANs, play a key role in the modulation of striatal function.

DALLAS – July 17, 2003 – Abnormally high calcium levels spurred on by a mutated gene may lead to the death of neurons associated with Huntington’s disease.  Below is an extract from Here

This discovery by researchers at UT Southwestern Medical Center at Dallas, published in the current issue of Neuron, sheds new light on the process that causes the selective death of neurons in the region of the brain called the striatum. Neurons in this area control emotions, body movements and several other neurological processes, including addiction.

Assistant Professor of Pharmacology and Toxicology.
(b. 1961); B.S. 1984, Case Western Reserve University; M.S. 1989, University of Pittsburgh; Ph.D. 1992, University of Pittsburgh; Post-doctoral fellow 1992-1995, NIMH.  Below is an extract from here.

My laboratory is interested in the structure and function of the basal ganglia, a group of subcortical nuclei in the brain involved in the control of movement and cognition. The importance of the basal ganglia for normal behavior is highlighted by the profound deficits observed in patients with Parkinson's disease, Huntington's disease, schizophrenia, and drug addiction -- diseases that are associated with dysfunction in the basal ganglia.

Cellular mechanisms of striatum-dependent behavioral plasticity and drug addiction.
Fasano S, Brambilla R.

San Raffaele Research Institute and University, Milano, Italy. Below is an extract from here.

The striatum has long been known to be involved in the control of motor behavior, since disruption of dopamine-mediated function in this brain structure is directly linked to Parkinson's disease and other disorders of movement. However, it is now accepted that both dorsal and ventral striatal nuclei are also essential for a variety of cognitive processes, which depend on reward-based stimulus-response learning. Since the neuroanatomical and neurochemical organization of dorsal and ventral striatum is only partially overlapping, it is likely that both common and nucleus-specific cellular and molecular events contribute to synaptic plasticity, learning and memory processes mediated by these cerebral structures. Alterations in cell signaling in the striatum may be particularly important in the response to both acute and chronic administration of drugs of abuse, resulting in maladaptive changes in the reward-based associative learning involved in addiction, withdrawal and relapse.

Below is an extract from Here.  

Psychiatric disturbances.  Individuals with HD develop significant personality changes (72%), affective psychosis (20- 90%), or schizophrenic psychosis (4-12%) [Mayeux et al 1986 , Folstein et al 1987 , Shiwach 1994 , Mendez 1994 , Cummings 1995]. Suicide occurs in up to 12% of individuals [Mendez 1994 , Cummings 1995]. Behavioral disturbances such as intermittent explosiveness, apathy, aggression, alcohol abuse, sexual dysfunction and deviations, and increased appetite are frequent [Folstein 1989]. Delusions, often paranoid, are common. Hallucinations are less common.