There is a strong agreement in the scientific community that there is no specific cause of emetophobia. Some emetophobics report a traumatic experience with vomiting, almost always in childhood, but many do not. Some suggest that sufferers are victims of childhood abuse – sexual or physical. While this is occasionally true, it seems to be no more prevalent than in the general population. (Christie, 2004) Some experts believe that emetophobia may be linked to worries about lack of control. Many people try to control themselves and their environment in every possible way, but vomiting is difficult or impossible to control.

There are many factors that can cause a legitimate case of emetophobia. It can affect the minds of young children, but emetophobia can also affect a person at any age. While some emetophobics are indeed severely mentally ill, many are not and have been diagnosed as such and treated inappropriately.

Dr. Angela L. Davidson "et al". conducted an experiment where it was concluded through various surveys that people suffering from emetophobia are more likely to have an internal locus of control pertaining to their everyday life as well as health-related matters. A locus of control is an individual's perception of where control comes from. Having an internal locus of control means that an individual perceives that they have their own control over a situation whereas an external locus of control means that an individual perceives that some things are out of their control.

She explains how this phobia is created through the locus of control by stating, "Thus far, it seems reasonable to stipulate that individuals with a vomiting phobia deem events as being within their control and may therefore find it difficult to relinquish this control during the act of vomiting, thus inducing a phobia."

In an internet survey conducted by Dr. Joshua D. Lipsitz et al. given to emetophobic people, respondents gave many different reasons as to why they became emetophobic. Among some of the causes listed were severe bouts of vomiting as children and being firsthand witnesses to severe vomiting in others due to illness, pregnancy, or alcoholism.

Exposure methods, using video-taped exposure to others vomiting, hypnosis, exposure to nausea and exposure to cues of vomiting Systemic behavior therapy, psychodynamic and psychotherapy have also shown positive effects for the treatment of emetophobia. However in some cases it may cause re-traumatization, and the phobia may become more intense as a result.

Anorexia nervosa has been increasingly diagnosed since 1950; the increase has been linked to vulnerability and internalization of body ideals. People in professions where there is a particular social pressure to be thin (such as models and dancers) were more likely to develop anorexia, and those with anorexia have much higher contact with cultural sources that promote weight loss. This trend can also be observed for people who partake in certain sports, such as jockeys and wrestlers. There is a higher incidence and prevalence of anorexia nervosa in sports with an emphasis on aesthetics, where low body fat is advantageous, and sports in which one has to make weight for competition. Family dynamics can play big part in the cause of anorexia. When there is a constant pressure from people to be thin, teasing, bullying can cause low self-esteem and other psychological symptoms.

Early theories of the cause of anorexia linked it to childhood sexual abuse or dysfunctional families; evidence is conflicting, and well-designed research is needed. The fear of food is known as "sitiophobia", "cibophobia", or "sitophobia" and is part of the differential diagnosis. Other psychological causes of anorexia include low self-esteem, feeling like there is lack of control, depression, anxiety, and loneliness.