Nedley's Depression Hit Theory
- Bree
- Jan 9, 2023
- 3 min read
In 2014, a study was published in hopes of enlightening us regarding predicting depressive episodes and establishing lifestyle changes that would prevent such episodes.
Nedley and his team established 10 "cause" categories (hits or blows to the brain) and then theorized that 4 or more "hits" at a time would trigger a depressive episode.
The conclusion to this study: "identifying these factors and applying lifestyle therapies could play an important role in the treatment of depressed individuals."
The Factors:
1. Genetic: Family history of depression or suicide in a first-degree relative
2. Developmental: Early puberty in girls (beginning menstruation by age 11 years or younger), history of depression in adolescence, not being raised by both biological parents, sexual abuse, and being raised or living with someone who is an alcoholic or drug addict
3. Lifestyle: Not on a regular aerobic exercise program, not regularly exposed to daylight or a medical-grade light box for at least 30 minutes a day, and rarely breathing fresh air.
4. Circadian Rhythm: Regular insomnia, routinely sleeping more than 9 hours per day or less than 6 hours per day, and not having regular hours for sleeping and eating.
5. Addiction: Use of alcohol, cigarette or tobacco use, heavy caffeine use, recreational drug use (including marijuana), daily use of benzodiazepines, or chronic narcotic use for more than 30 consecutive days.
6. Nutrition: Low dietary tryptophan; low omega-3 fat intake; low folic acid intake; low vitamin B intake; diet high in cholesterol, saturated fat, and sugar; and marked anorexia and weight loss.
7. Toxic: High lead levels; high mercury levels; high arsenic, bismuth, or other toxin levels; or high risk of exposure to these toxins.
8. Social/Complicated Grief: Absence of social support, negative or stressful life events, low social class, being raised by grandparents, and immediate family member being an alcoholic or drug addict.
9. Medical Condition: Hepatitis C, recent head injury, stroke, heart disease, terminal cancer, Parkinson’s disease, uncontrolled diabetes, severe postpartum stress, premenstrual tension syndrome, inadequately treated thyroid disease, lupus, inadequately treated adrenal gland disease.
10. Frontal Lobe: On low carbohydrate diet, on high meat or high cheese diet or eating lots of rich food, entertainment TV or movie addiction, entertainment Internet or chat Internet addiction, frequent sexual stimulation that activates right frontal lobe, regular exposure to syncopated rhythm music and/or videos, conscious suppression of frontal lobe activity, lack of regular abstract thinking, acting against one’s conscience or known value system.
"Of these 10 hits, only the genetic and the developmental are not reversible. Most of the other reversible hits are directly related to lifestyle choices."
"Improving lifestyle and decreasing the number of hits not only helped the participants who were depressed but also those who were not depressed. According to the results of the before and after tests, they were able to improve their overall lifestyle, nutrition, health habits, and frontal lobe function as measured by their resulting hits.
Given the many potential causes of depression, it is truly amazing that even more people do not develop this prevalent mental disorder. We have found from our depression programs that the brain is resilient and can typically stand up to a combination of 3 risk factor categories and still function correctly. However, when the fourth risk factor category is added, even the healthiest brain will often develop major depression. The long list of possible factors that can contribute to or cause depression should highlight the importance of carefully considering causative factors. Because many of these factors are directly related to lifestyle choices, we foresee the future treatment of depression depending more on lifestyle changes than pharmacological treatment."
Nedley, N., & Ramirez, F. E. (2016). Nedley Depression Hit Hypothesis: Identifying Depression and Its Causes. American journal of lifestyle medicine, 10(6), 422–428. https://doi.org/10.1177/1559827614550779
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