One of the most common issues in troubled ADHD/non-ADHD partnerships is that of parent/child dynamics. That is, a non-ADHD partner becomes the partner in control, while an ADHD partner loses authority. This is typically a result of a couple's interactions around undermanaged ADHD symptoms. As in one example, an ADHD partner might promise to finish a chore around the house, but then get distracted (an ADHD symptom) and forget. The non-ADHD partner might remind the ADHD partner, who might well become distracted again. Eventually, the non-ADHD partner decides it's easier to do it herself (or himself) and takes the task on. (Or, perhaps takes responsibility for the task's completion by reminding the ADHD partner about it until it gets done.)
The problem with this interaction is that over time it will put too much responsibility on the shoulders of the non-ADHD partner. ADHD symptoms are chronic, not temporary, and until treatment strategies are in place the distraction, memory issues or other symptoms that drive the inconsistency of the ADHD partner will persist.
Parent/child dynamics usually start well before couples know about ADHD. Non-ADHD partners often have good organizational skills and they often don't mind using those skills in the service of their relationship. But at some point - often when a couple starts having a famiy—there are simply too many responsibilities for the non-ADHD partner to shoulder. To keep her life from blowing apart in the face of the chaotic nature of ADHD, the non-ADHD partner starts to ask for more assistance. When ADHD symptoms get in the way of that assistance, the non-ADHD partner adapts by taking more control. He or she becomes a 'parent figure' while the ADHD partner is deemed inconsistent or untrustworthy.
We typically think of adaptation as healthy in a relationship. And in some situations, it is. But research by John Gottman shows a strong link between healthy relationships and those in which women (in particular) don't adapt to problems early in a relationship. Instead, presumably, they bring issues to light immediately and negotiate solutions with their partners before the problems become unmanageable.
The unbalanced power in a parent/child adult relationship tends to be negatively reinforcing. The more power a non-ADHD partner wields, the more resentful the ADHD partner tends to become, sometimes leading to active resistance to the more powerful non-ADHD partner. That resistance discourages the effort needed to treat ADHD symptoms in a way that will improve reliability and increase power for the ADHD partner. In addition, being the 'childlike' partner in the parent/child dynamic is debilitating. When the 'story' of the relationship becomes that one partner is incompetent, both partners may find ways to reinforce that message or, perhaps, interpret events through that lens.
Parent/child dynamics are not much fun for the non-ADHD partner, either. Few adults want to feel as if the only way something will get done is if they boss their partner around or nag. Nor do they want the crushing responsibility that taking on so much of their partner's work entails. Parent figures typically become very frustrated and short with their partners, and long for the support of another "competent adult" figure in their life.
And, of course, an unbalanced partnership is not at all romantic. Who wants to be intimate with a parent figure…or a 'child figure'?
Having ADHD in your relationship does not in any way guarantee that parent/child dynamics will ensue. However, having parent/child dynamics will almost always result in marital dysfunction. Moving away from the unequal power structure of parent/child dynamics is critical to the success of ADHD-impacted relationships.
More information about parent/child dynamics can be found in The Couple's Guide to Thriving with ADHD, due to be released in April of 2014.