Drug abuse and addiction affect women and men differently, according to new studies presented at the annual meeting of the American Psychiatric Association. Some of the speakers asserted that this knowledge of gender-based differences should be used in pharmacological and behavioral treatments for addiction.
Women begin using drugs at lower doses then men, their drug use escalates more rapidly into addiction, and they face a greater risk of relapse after abstinence, according to Jill Becker, PhD, professor of psychology at the University of Michigan, Ann Arbor. In addition to the direct evidence from humans, laboratory animals show the same kind of gender differences in addiction. Studies by Christine E. Grella, PhD, research psychologist at the University of California, Los Angeles also show that women tend to enter treatment sooner after becoming dependent on substances than men, but they usually have more psychological distress, particularly with mood and anxiety disorders.
Addiction is widely considered a disorder of the memory processes, and over the past several years, studies have shown strong hemispheric gender differences in how the brain responds to memory processing after seeing emotionally arousing material. For example, men show stronger responses in the right amygdala, and women have stronger responses in the left amygdala. This research may help to explain previous evidence for effects of the menstrual cycle on craving in addition to gender differences in the effectiveness of addiction treatments such as the nicotine patch.
Karen Faith Berman, MD, and colleagues at the National Institute of Mental Health in Bethesda, Maryland, had found that fluctuations in steroid hormone levels during the menstruation cycle affect neurological responses to rewards. When anticipating an uncertain reward, men showed more activity in the ventral putamen than women; when receiving a reward, women showed more activity in the anterior medial prefrontal cortex than men.
Becker’s team has also found significant gender differences in the concentration and location of receptors for the neurotransmitter dopamine, which controls anticipation and reward. The female hormone estradiol enhances dopamine release among women, for example. “Since the effect of estradiol is seen only in females,” Becker said, “this mechanism may offer unique pharmacological opportunities for the treatment of drug abuse in women.”
Cocaine also seems to dampen normal gender differences in response to stress, craving, and relaxation, said Marc N. Potenza MD, PhD, associate professor in the department of psychiatry at Yale University.
Larry Cahill, PhD, associate professor of neurobiology and behavior at the School of Biological Sciences, University of California, Irvine, said, “It is dangerous at best, and completely wrong at worst, to assume that any neurological disorder has the same underlying causes in men and women, and thus to assume that treatments for the disorder will be essentially the same…Yet that is precisely the assumption that continues to pervade much of both the clinically applied and basic science worlds.”
Source: Psychiatric Times, May 2009