Here, 'sex' refers to gender assigned at birth (hormonal profile, chromosomal complement). 'Drugs' refers to all licit and illicit substances (incl alcohol, nicotine, caffeine, cannabis, psychedelics, amphetamines, club drugs/MDMA, opiates, sedatives, inhalants, etc).
There are well-known sex differences in drug and alcohol use disorders. Women initiate use of some drugs at an earlier age, transition from first use to harmful use more quickly, experience more severe symptoms, are more susceptible to toxic drug and alcohol effects, are less likely to receive treatment, and show worse treatment outcomes than men. Thus, there is an urgent need to understand why women are more at risk to the harmful effects of drug and alcohol use, and to develop more successful therapies for women.
Ovarian hormones (estrogen, progesterone) are thought to play a role in the increased risks from drug use among women. Estrogen and progesterone are known to influence the effects of drugs differently. So, as these hormones fluctuate across the menstrual cycle, the effects of drugs and alcohol may also vary. Thus, if the strength of drug and alcohol effects differs from one day to another, it becomes much more difficult to adjust and control consumption.
We are currently studying how natural and synthetic ovarian hormones alter the effects of alcohol and other drugs on mood and behavior. Our goal is to better understand hormone-related variation in drug effects how this influences risk for hazardous drug use. Ultimately, we hope the findings will advance more effective treatment approaches for women.
Drug and alcohol use disorders can be treated with current therapies. However, many people experience relapses to drug use. A major barrier to long term successful treatment of drug and alcohol disorders are learned associations between the drug and the people, places, and paraphernalia (called ‘cues’ or ‘triggers’) linked with previous drug experiences. These memories are remarkably persistent and can cause relapse to drug use even after long periods of abstinence. Drug:cue associations are also a key feature in some of the foremost theories of addiction, yet there is little clinical evidence of how these associations are formed and how they come to profoundly control behavior. The long-term goal of this line of research is to understand how drug cues become powerfully linked with drug experiences, how they influence cognition and behavior, and how they promote drug consumption and development of substance use disorders. We hope that this knowledge will help us to develop therapies that target drug:cue associations to promote long term recovery and prevent relapse.
Drug Effects on Mood
It is thought that psychoactive substances are primarily consumed for the pleasurable mood states that they produce (at least during initial use). Thus, in our studies we measure how drugs change mood and emotions, and how strong these effects are. There is wide variation in the emotional experiences produced by a given drug between different people. For example, alcohol produces a wide range of different effects between people; in some people it produces positive rewarding stimulant-like effects while in others it produces primarily negative sedative effects. An individual's sensitivity to the positive mood effects produced by drugs like alcohol can influence their susceptibility to continue using that drug and go on to develop problematic use disorders. But, we don't know why some people experience positive alcohol effects and others don't. We also don't know why the strength of effects differs between people. If we have a better understanding of the factors that cause different drug experiences, we will be able to design new treatment approaches tailored to an individual's specific needs and develop personalized therapies.