PTSD and Alcohol Addiction

Trauma and Learned Helplessness
by National Institute of Health

(Page 2 of 4)

Research in the past quarter century has shown that experiencing trauma does not necessarily lead to psychopathology. It is not uncommon for people to experience a traumatic event. As much as 70 percent of the U.S. population has experienced at least one trauma, such as a traffic accident, assault, or an incident of physical or sexual abuse. Many people are able to cope with their traumatic experiences and do not suffer from prolonged consequences. For about 8 percent of the population, however, the consequences of experiencing trauma do not abate and may indeed get worse with time. The degree to which a person or animal can control a traumatic event is an important factor in understanding the impact of the event. In fact, an event can have very different effects depending on the victim's ability to cope with the event. Children who are victimized have very little control over the traumatic event and may experience severe emotional distress as a result.

After experiencing uncontrollable traumatic events, animals and humans show physiological, behavioral, and emotional symptoms of distress. For example, rats that have been exposed to shocks that they cannot control often become strikingly passive when later placed in new traumatic situations. They appear numb to the new trauma as if they have "given up." Alternatively, they also become especially fearful of environments where they experience similar traumas and will try to avoid such situations. Seligman and colleagues termed this behavior "learned helplessness".

In addition, animals exposed to uncontrollable footshocks, unlike animals exposed to electric footshocks that they can escape, show depletion in catecholamines and elevations in stress hormones. These biochemical changes are associated with organic diseases such as gastric ulceration, immunosuppression and even decreased resistance to the injection of tumor cells. For example, in one study rats were given injections of cancer cells following experience with shocks that were either uncontrollable, controllable, or nonexistent. The rats that received the uncontrollable shock (the learned helplessness rats) were less able to resist the cancer cells, and less than one-third survived. In contrast, some rats experienced the same intensity electric footshock but could turn off the shock by pressing a lever. Two-thirds of these rats survived. Other rats were placed in the shock compartments but experienced no shocks. A little more than half of these rats survived.

Learned Helplessness and PTSD

The grouping of symptoms that follow experience with uncontrollable trauma is called "learned helplessness effects". As described above, animals that experience uncontrollable trauma learn that their responses are of no consequence, leaving them helpless to cope with a traumatic situation.

Although originally proposed as an animal model of depression, learned helplessness has many similarities with PTSD. Both PTSD and learned helplessness develop following exposure to negative stressors or uncontrollable events. In addition, learned helpless animals and patients with PTSD suffer from a variety of similar behavioral symptoms, such as increased generalized arousal (marked by exaggerated startle response or hypervigilance). For example, someone with PTSD may easily jump when he or she hears a car backfire, responding as if a gun had been fired. Similarly, after experiencing uncontrollable trauma, rats will be fearful in an open field and hesitant to venture out and explore the environment. Both conditions are associated with anticipatory fear prompted by situations that resemble the traumatic event. If reexposed to the traumatic event, both animals and humans more easily "give up" and appear strikingly passive. The biochemical changes observed in animals following uncontrollable trauma parallel those changes sometimes seen in humans following uncontrollable traumatic events. Stress hormone levels are often elevated between episodes of trauma. Also, as is the case with animals exposed to uncontrollable stress, patients with chronic PTSD have high rates of medical problems, such as autoimmune diseases.

Another similarity between learned helplessness as seen in animal models and PTSD is the co-occurrence of excessive alcohol consumption. In an experiment in which some rats were exposed to shocks they could escape from and others were exposed to shocks that were inescapable, rats that were presented with inescapable shocks increased alcohol preference compared with rats that received escapable shocks. The rats' alcohol consumption did not increase on the days that they experienced the shocks, however, but did increase 1 day later.

The behavioral and physiological similarities between learned helplessness in animals and patients with PTSD suggest that learned helplessness is a good model to understand PTSD.

Poststress Alcohol Consumption

In both animals and humans, traumatic events and increased alcohol consumption are clearly related; but alcohol use typically increases following the trauma, rather than during the trauma. Much of the confusing literature on stress and alcohol use is understood better when one assesses alcohol use in relationship to when the trauma occurred. For example, in a study with rats we found very modest increases in alcohol consumption on days when shocks were administered but dramatic increases in alcohol preference on subsequent days. We termed this the "happy hour effect" and have noted that even among social drinkers, alcohol consumption increases following, but not during, exposure to stress. These results were the opposite of what we expected based on a tension-reduction theory of alcohol use. If one uses alcohol solely to reduce anxiety, alcohol consumption should increase during times of stress rather than after the stress.

Research in humans has also identified a strong association between PTSD and alcoholism. For example, in a sample of Vietnam combat veterans with PTSD, more than half subsequently showed signs of alcohol addiction. Similarly, women exposed to childhood rape often report turning to alcohol to reduce symptoms of PTSD. In addition, investigators found that 40 percent of inpatients receiving treatment for substance abuse also met criteria for PTSD.

About the Author

NIH is the nation's medical research agency - making important medical discoveries that improve health and save lives. The National Institutes of Health (NIH), a part of the U.S. Department of Health and Human Services, is the primary Federal agency for conducting and supporting medical research.