Describe symptoms and prevalence of two disorders (anxiety, affective, or eating disorders)
Prevalence is a statistical concept in medicine (or psychiatry). It refers to the percentage of individuals within a population who are affected by a specific disorder either currently or during their lifetime. Prevalence rates change cross-culturally and between genders.
Affective disorder: major depression
Typical symptoms of major depression (depressive episodes without mania) according to the DSM-V include
- Physiological: Fatigue or loss of energy, significant weight loss or gain, loss of appetite, headaches, and pain.
- Cognitive: Feelings of worthlessness or excessive guilt; difficulties concentrating; negative attitudes towards the self, the world and the future. (Feelings of guilt and worthlessness seem to be symptoms that are primarily experienced in Western cultures).
- Emotional: Distress and sadness, loss of interest in the world.
- Behavioral: Disturbed sleep patterns, self-destructive behavior (suicidal thoughts), and avoidance of social company.
- The National Comorbidity Study (1994) found that prevalence for lifetime major depression in the USA was 17.1%.
- The National Institute of Mental Health (NIMH) in the USA found that lifetime prevalence of depression was 16.6% with 13.2 % for males and 20.2 for females (Kessler et al. 2005).
- Andrade and Caraveo (2003) found that lifetime prevalence of depression varies across cultures (e.g. 3% in Japan and 17% in the USA).
- Kessler et al. (1993) found a lifetime prevalence for major depression of 21.3% in women compared to 12.7% in men.
Eating disorder: bulima nervosa
Typical symptoms of bulimia according to the DSM-IV-TR include:
- Physiological: Nutritional deficiencies and hormonal changes could lead to disturbances in the menstrual cycle, fatigue, digestive problems, muscle cramping.
- Cognitive: Distorted body image, low self-esteem, sense of lack of control during binge-eating episodes
- Emotional: Fear of becoming fat (fat phobia), body dissatisfaction, and depressed mood.
- Behavioral: Self-starvation in combination with recurrent binge eating episodes and compensatory behavior such as vomiting and misuse of laxatives to avoid weight gain.
- Fairburn and Beglin (1990) found that bulimia nervosa affected between 1 and 2 % of young women in the USA and the UK. APA (200) estimated 1–3% of young adult females to have Bulimia. The disorder occurs much less frequently in men.
- Drewnowski et al. (1988) conducted a telephone survey with a representative sample of 1,007 male and female students in the USA. They found that 1% of the women and 0.2% of the men were classified as bulimic. Bulimia nervosa was most prevalent among undergraduate women living on campus (2.2%).
Keel and Klump (2003) performed a meta-analysis of research on bulimia nervosa and found an increase in people diagnosed with bulimia from 1970 to 1993. There are no incidence data for bulimia prior to 1970. The diagnostic criteria for bulimia have become more stringent over the years and this has resulted in the increase of incidences. According to the researchers, self-report surveys tend to produce higher estimates of bulimia nervosa prevalence than structured clinical interviews.