The Effects of Candida On Mental Health by William Crook, M.D.

author of a million copy bestseller published in the 1980s and The Yeast Connection Handbook, which provides new information for the 21st Century
The Yeast Connection Handbook


Yeasts are single-cell living organisms that are neither animal nor vegetable. They live on the surfaces of all living things, including fruits, vegetables, grains and your skin. They’re part of the “microflora” (tiny plants) which contribute in various ways to the health of their host. Yeast itself is nutritious and small amounts of yeast gives bread its good yeasty taste. Yeast is a kind of fungus. Mildew, mold, mushrooms, monilia and candida are all names that are used to describe different types of yeast.
One family of yeasts, Candida albicans, normally lives on the inner warm creases and crevices of the digestive tract and vagina. When your immune system is strong, candida yeasts cause no problems. But when you take broad-spectrum antibiotics for such conditions as acne, respiratory infections or cystitis (bladder infection), these drugs knock out friendly germs while they’re knocking out enemies.
Candida yeasts aren’t affected by antibiotics so they multiply and raise large families. These yeasts put out toxins that weaken the immune system.. So you may experience repeated infections. Each infection is treated with another round of antibiotics, encouraging further yeast overgrowth, and a vicious cycle develops.
A diet rich in sugar and other simple carbohydrates promotes yeast overgrowth.
The “yeast connection” is a term to indicate the relationship of superficial yeast infections in your digestive tract (or vagina) to fatigue, headache, depression, PMS, irritability, and other symptoms that can make you feel “sick all over.”
Many of these problems develop because your immune system, your endocrine system and your brain are intimately related.
Other causes must also be considered. If you’re like most people with a candida-related health problem, you resemble an overburdened camel. To regain your health, to look good, feel good and enjoy life, you’ll need to unload many “bundles of straw.” This may take months – even a year or two – but then your camel will be off and running.
Millions of Americans suffer from depression. Many of them have taken Prozac, Zoloft and other medications. These medications, like many others, may cause adverse reactions. Because of these possibilities, many therapists say that these drugs should not be given to people without looking for the underlying physical and psychological causes of the person’s depression.
Like fatigue, headache, PMS and other chronic complaints, depression may develop from many different causes. Moreover, such causes are often multiple. In my experience and that of many other practicing physicians, Candida albicans ranks high on the list…especially in women between the ages of 25 and 45.
If you suffer from depression and/or any other disabling disorder and have a history of…
  • Repeated or prolonged courses of antibiotic drugs
  • Persistent digestive symptoms
  • And/or recurrent vaginal yeast infections, prostrate infections, jock itch or nail fungus…
…a comprehensive treatment program that features oral antifungal medications and a special diet may provide you with sometimes dramatic relief from recurring depressions.
Manic Depression
During the past few years, I’ve received a number of letters from people with manic depression who responded to antifungal therapy. Here are excerpts from a New Zealand woman’s story, which I found to be especially dramatic:
“Imagine the whole world spray painted gray or being in a small windowless cell or in a tunnel. I felt that I had 50-pound weights on each foot and all my favorite things suddenly became meaningless and sterile.
“If someone had given me two round-trip air tickets to London and Paris and $15,000 spending money, I would have been completely unmoved. Nothing could trigger a flicker of interest or enthusiasm…”
Then, after a week or two of this hell, she would swing into a manic world of exhaustion and even delirium.
“I was king of the castle, drunk with joy, bursting with crazy schemes, talking nonstop, spending money like water, issuing dinner and party invitations, smashing up the car. You’d have to have seen it to believe it…”
This woman struggled with her depression for eight long years. She was put into a psychiatric hospital and received out-patient therapy for many months.
Then a general practitioner prescribed a diet, nystatin (an antibiotic for treating candida), and nutritional supplements. On this treatment program the bouts of mania stopped immediately, and the depressions became brief and much less severe; within three months they disappeared.
In the early 1980’s I saw a five-year-old boy who had been troubled with recurrent ear infections and hyperactivity during the first two years of life. Yet his developmental milestones were normal until the age of two and one half when specialists at a university center made a diagnosis of “pervasive developmental disorder with symptoms of autism.”
On a comprehensive treatment program that included nystatin, a special diet and the avoidance of chemical pollutants, the child improved significantly – even dramatically although he continued to experience developmental problems.
During the 1980’s, Bernard Rimland, Ph. D., of the Autism Research Institute, told me he had received numerous reports from parents whose autistic children improved following anticandida therapy. During the late 1980’s, I saw several more children in my practice with autistic-like symptoms who improved on a sugar-free, special diet and nystatin. All through the 1990’s, I received many, many calls and letters form parents of autistic children.. Almost without exception, autistic symptoms in these children first appeared during the second and third years of life following repeated ear and other infections.
The October 1994 issue of Autism Research Review International included a two-page review, “Parents Ratings of the Effectiveness of Drugs and Nutrients.” Here are excerpts from this report:
“The parents of autistic children represent a vastly important reservoir of information of the benefits and adverse effects…of the large variety of drugs and other interventions that have been tried with their children…The data presented in this paper have been collected from the more than 8,700 parents who have filled out questionnaires designed to collect such information…
“The 31 drugs listed first were prescribed by the child’s physician in each case. Note that Ritalin, the drug most often prescribed, is near the bottom of the list. Only 26 percent of the parents reported improvement, while 46 percent said the child got worse on Ritalin.”
I studied the charts in the report and I noted that nystatin ranked higher than any other prescription drug. Of the 208 children who were given one of these medications, 49 percent found that the child was “better” on the nystatin and only four percent said that the child was “worse.” The better/worse ratio was more than 12 to 1.
By contrast, none of the other drugs showed a better/worse ratio of more than 2.7 to 1 and many prescription medications, including Ritalin, which was given to 1,661 children, showed a better/worse ratio of 0.5 to 1. (This means that twice as many children were made worse by Ritalin than were helped.)
In other research, William Shaw, Ph. D., and colleagues in studies of children with brain dysfunction found elevated fungal metabolites and other abnormal acids in the urine of children with autism and ADHD. Following treatment with the antifungal medications and dietary changes, all of the autistic children improved.
Autism, like many other chronic and often devastating disorders, develops from many different causes. Yet there’s now clear evidence that in many children it is yeast-connected.
Children with ADHD often give a history of repeated ear infections in infancy. Such ear problems are usually treated with amoxicillin and/or other broad-spectrum antibiotic drugs. A research study found that 69% of children being evaluated for school failure who were receiving medication for hyperactivity gave a history of greater than ten ear infections. By contrast, only 20% of non-hyperactive children had more than ten infections.
Antibiotics wipe out friendly bacteria in the gut while they’re knocking out enemies. As a result, the usually benign microorganism, Candida albicans, multiplies. Based on research studies, candida puts out toxins which affect the nervous system, the immune system and other parts of the body.
I sent questionnaires to 16 practicing physicians interested in the management of children with ADHD. Five of the responders said that antiyeast therapy was “very effective” in managing these children and eight said it was “somewhat effective” in managing these children. One responder said it was “not effective” and another responder said he had not tried this therapy. Diet is another factor. Although I didn’t know that systemic and nervous symptoms in my pediatric patients could be yeast-related, beginning in the late 1950’s I learned that such symptoms were often caused by food sensitivities. Common troublemakers included especially milk, wheat, corn, chocolate and egg.
Yet it wasn’t until the early ’70’s that I learned that the ingestion of cane, beet or corn sugar was an important cause of hyperactivity – even though I didn’t understand the mechanism. In the 1970’s, at the suggestion of the late Dr. Amos Christie (my pediatric chief at Vanderbilt), I kept a record of every new patient who came to see me because of complaints of hyperactivity, attention deficits and other behavior and learning problems.
During a five-year period I saw 182 children with these complaints. Most were between four and eight years old. Each child was given a comprehensive workup which include a carefully planned and executed seven-day elimination diet. The eliminated foods included beet and cane sugar, milk, wheat, corn, egg, chocolate, yeast, citrus and food coloring and additives. If and when the child’s symptoms improved (as they usually did), the eliminated foods were returned to the diet one food per day and reactions were noted. At the end of a five-year period, through questionnaires and personal and telephone interviews, I obtained the following information:
Seventy percent (128) of the parents were absolutely certain that their child’s hyperactivity was related to specific foods in the diet.
The foods causing hyperactivity in 136 children included: sugar, 77;colors, additives and flavors (especially red food coloring ), 48; milk, 38; corn, 30; chocolate, 28; and wheat, 15.
Many other foods were reported as causing trouble.
As a final note on Candida and mental health, Dr. Carl Pfeiffer, one of the pioneers in the nutritional treatment of mental disorders, noted in his book Nutrition and Mental Illness that chronic Candida infection is one of the less well-known causes of schizophrenia..
You can get well!! And believing that you can is the first important step. Read, study, and learn. Be responsible. Although you’ll need help from kind and caring health professionals, you must make the major decisions. With an educated understanding, you can make the choices that will improve life for yourself or the ones you love.
For more information about the relationship of candida yeasts to health problems which affect people of all ages and both sexes, read Dr. Crook’s latest book, The Yeast Connection Handbook and visit
You’ll find information about Dr. Crook’s other books and the International Health Foundation. This small, nonprofit foundation was established in 1985 to respond to thousands of people seeking help for yeast-related problems. It was approved as a tax- exempt organization in 1986.
P.O. BOX 3494