Psychology also helps us to understand the causes of alcohol addiction. Addiction is a harmful behavior. Psychological research has helped us to understand why people repeat certain behaviors, even when these behaviors are harmful. This is because people learn to anticipate some benefit from the addiction even though it is harmful. These benefits can range from stress reduction, relief from boredom, pleasurable sensations, coping with negative feelings or situations, or simply the benefit of avoiding withdrawal symptoms. People have varying abilities to cope with unpleasant emotions or circumstances. When people have poor coping skills they are more vulnerable to addiction. Likewise, people have varying degrees of stress and varying skills in stress reduction. People with high stress, that lack stress reduction skills, are also more vulnerable to addiction. Psychological research also helps us to understand that motivation is critical. Without sufficient motivation, people cannot easily change unhealthy behaviors. Simply being aware of an alcohol problem is usually insufficient motivation to discontinue unhealthy behavior. However, psychologists can help strengthen people's motivation through therapy and specialized techniques. Many psychological disorders such as depression and anxiety often co-occur with addiction. These other psychological disorders make people more vulnerable to addiction. This is because people may use alcohol to temporarily relieve the unpleasant symptoms of these disorders.