There is a relatively recent publication that came out within the last couple of weeks on the relatively high rate of occurrence in bed wetting (enuresis) among ADHD children, which I believe is worth sharing. We have previously investigated this ADHD and bed wetting connection (note that bed wetting may be more likely to be seen alongside the inattentive subtype of ADHD). However, this study offers some additional insight into this strange association between the two disorders. Here are some important points worth mentioning:
- Overlapping Drug Treatment for ADHD and bedwetting: It stands to reason that if a particular drug or agent is effective in treating multiple disorders, there may be a distinct possibility that those two or more disorders may share some type of underlying cause(s) or defect(s). For example, Tofranil or Imipramine, a drug used to treat enuresis and depressive disorders can possibly be useful as a treatment option for ADHD. We have also investigated the potential role of Reboxetine as a potential ADHD treatment in previous entries. Some work has found Reboxetine to be useful in treating therapy-resistant enuresis as well.
- Prevalence of Enuresis in ADHD: Enuresis refers to urinary incontinence which is limited to the night-time. Additionally, the term is typically limited to individuals over the age of 5 (i.e. a 3-year-old child who frequently pees in their pants would not be considered as suffering from enuresis, at least in the context of this study). The article cites other studies in which the rate of bedwetting (enuresis) in ADHD is as high as 30%, although other studies have it down around 10-20%. Still, compared to the general population, (factoring in things such as the age of the child, of course)the high rate of bed wetting in ADHD is especially noteworthy. There is some evidence from other studies that ADHD and enuresis may be more intricately linked than previously imagined. For example, one particular study has shown that treating urinary incontinence has a higher rates of failure in children with ADHD vs. non-ADHD children.
- The role of Oppositional Defiant Disorder (ODD) on Bed wetting: The study examine several different psychiatric disorders which frequently occur alongside of (or are comorbid to) ADHD. These include depression, anxiety disorders, obsessive compulsive disorders, tic disorders, nail biting, bruxism (teeth grinding), conduct disorders and oppositional defiant disorders. However, out of all of these different disorders which often appear alongside ADHD, the only one which exhibited a statistically significant correlation to increases in bedwetting was oppositional defiant disorder. Interestingly, oppositional defiant disorders have been associated with bedwetting in other ADHD studies.
As its name suggests, Oppositional Defiant Disorder is a disorder in which a child exhibits disobedience, irritability and hostility towards authority figures beyond the range of normal age-appropriate behaviors. Of course there is a significant gray area with regards to what is age appropriate, especially when the child's environment is considered. Nevertheless, Oppositional Defiant Disorder (or ODD) is much more than just routine temper tantrums. Oppositional Defiant Disorders may also be associated with auditory processing issues and ADHD. It is somewhat interesting that anxiety disorders, which have also been correlated to oppositional behaviors, did not elicit a significant positive correlation to bed wetting. - The autonomic nervous system as a potential underlying cause of ADHD, bedwetting and Oppositional Defiant Disorders: The autonomic nervous system is the part of the nervous system responsible for involuntary muscle actions such as digestive processes, blood vessel contraction, etc. It is subdivided into the sympathetic and parasympathetic nervous systems, which often act in a sort of "push-pull" opposition to each other. For example, the sympathetic nervous system does things such as boosting heart rate and constricting blood vessels, while the parasympathetic nervous system is in charge of activities such as reducing heart rates and relaxing sphincter muscles (which plays a role in bladder control).
Typically, the sympathetic and parasympathetic components of the nervous system are kept in balance, but this balance may be thrown out of whack and result in numerous disorders. For example, it is believed that the parasympathetic nervous system is over dominant in cases of Oppositional Defiant Disorders (ODD). The study found that for ADHD and Oppositional Defiant Disordered children, functions such as heart rate were controlled excessively (if not almost exclusively) by the parasympathetic portion of the nervous system (while non-ODD and non-ADHD children had both sympathetic and parasympathetic controls operating on their heart rates. This suggests a common underlying imbalance among the different components of the nervous system which is common to ADHD and ODD individuals and often separates them from the non-ADHD'ers. Interestingly, other studies have indicated that bedwetting or generalized incontinence problems may also be caused by an overactive parasympathetic nervous system, which suggests that ADHD, ODD and night-time bedwetting may all share some underlying causes within the nervous system.
- Connection to Parental Depression: I personally found this observation to be interesting. The study found that the prevalence of bedwetting in ADHD children was higher if the father (but not the mother) of the child was suffering from some sort of major depressive illness. The article did not express an opinion as to whether these depressive symptoms were due in part to the child's bed wetting problems or whether there was some underlying mechanism at work.
- ADHD medications may Influence Enuresis: The authors highlight some other works in which popular ADHD medications may either increase or decrease the risk of bedwetting in ADHD children. For example, the article highlighted a case study (by the same author) in which treatment with methylphenidate induced nocturnal enuresis. Methylphenidate is one of the most common ADHD drugs, and often goes by the common trade names Ritalin, Concerta, Metadate and Daytrana (the patch form of the drug). Of course this is based on only one individual case, but for those of you who have read this blog on a frequent basis, will know that I like to report on some of these abnormal occurrences (for reference sake, here is an earlier blog post I have done on the possible connection between methylphenidate and excessive talking. While based on an isolated case report, I believe that this zany potential side effect was at least worth a mention). On the flip side, however, the non-stimulant alternative ADHD drug, Atomoxetine (Strattera) can be a useful treatment for enuresis. This blogger would personally like to see additional studies on whether ADHD children with a comorbid bedwetting condition actually saw a better reduction in their ADHD symptoms while on Strattera than while on methylphenidate. If this were the case, then bedwetting may actually served as a useful tip-off as to which type of ADHD medication would work best for that particular child.