12/11/09 – The annual meeting of the American College of Neuropsychopharmacology was told this week that pathological gambling can be successfully treated with medications that decrease urges and increase inhibitions.
Researchers presented findings that show positive outcomes in gamblers treated with medications often used for substance addictions.
Dr. Jon Grant and his team at the University of Minnesota used tasks that measure cognition to identify what motivates this extreme type of gambling behaviour. They enrolled men and women with a primary diagnosis of pathological gambling in one of three medication studies.
Study sites varied in size from 70 to 100 participants.
In order to group individuals into categories that address differences in their biology, Grant separated pathological gamblers into two major subtypes: gamblers who are driven by urge (i.e., individuals who report gambling when the desire becomes too strong to control), and those who do not show normal inhibition of impulsive behaviours (i.e., individuals who report being unable to restrict behaviours even when urges are minimal or virtually non-existent).
In the first subtype, gamblers who are driven by urge responded well to treatment with medications that block the brain opioid system (e.g., naltrexone) or certain receptors for the neurotransmitter glutamate (e.g., memantine).
Grant also found that family history plays an important role in refining this group even further. People with a family history of addiction responded even better to the opioid blocker, which has been shown in other studies to decrease the urge to use substances such as alcohol.
The second subtype, gamblers who have difficulty inhibiting their behaviours and react to the smallest desires, respond well to medications that act on a specific enzyme, catechol-O-methyl-transferase (COMT), which plays a major role in the function of the prefrontal cortex.
Researchers found that decreasing the function of COMT can increase one's ability to inhibit their desire to gamble.
"By understanding these different subtypes, we are able to target the core biology of the illness with individualized treatment," said Jon Grant, MD, JD, MPH, Associate Professor of Psychiatry at the University of Minnesota and ACNP member.