Do you remember? Memory problems in adults with attention deficit hyperactivity disorder (ADHD)
Classic symptoms of ADHD are problems in attention and impulsivity. Many individuals with ADHD have problems focusing attention, are easily distractible, or have difficulties sustaining attention over a longer period of time. Numerous studies showed that cognitive impairments in ADHD are also linked to problems in executive functions, a term used to describe higher processes of cognition such as planning, organizing, strategizing, switching between tasks and inhibition.
“Memory functions of adults with ADHD, however, have been widely neglected in research for a long period of time. This is surprising as many patients with ADHD report to often lose things, to not follow through on instructions or to be forgetful in daily activities. This is even more surprising considering that some of these behaviors are indicative of the presence of ADHD as outlined in international diagnostic criteria.”
In a recent series of studies, we examined memory functioning of adults with ADHD using various tests. For example, we presented participants lists of incoherent words, we read out short stories depicting coherent events and we outlined rules of certain planning tasks. At a later time, we asked participants to recognize the words, to recall the stories as well as to perform planning tasks which have been presented before (Fuermaier et al., 2013a; Fuermaier et al., 2013b).
Our results clearly indicated that our participants with ADHD suffered from considerable impairments in memory, thereby showing that ADHD is a disorder not exclusively associated with obvious problems in attention and executive functions. Thorough analysis further revealed that these impairments in memory functioning were largely caused by executive dysfunctions, such as deficits in planning and organizing. For example, we found that adults with ADHD were (1) inefficient in storing new information in memory and (2) also had problems in retrieving the information from memory storage when a recall was required. Learning new information as well as recalling information from memory storage requires high organizational skills in which adults with ADHD have commonly problems (e.g. clustering words with similar meaning, creating memory hooks, strategic and systematic recall of all information). However, we also demonstrated that adults with ADHD had intact abilities in retaining information in memory once information was successfully stored. This means that core memory functions of adults with ADHD appear to be intact.
“Even though adults with ADHD report to encounter considerable memory problems in daily life, these problems are most likely not caused by forgetfulness but may rather result from impairments of encoding (at the time when information is learned) and retrieval (at the time when stored information is recalled).”
In addition, we showed that executive dysfunctions of adults with ADHD also adversely affect prospective memory and source memory, two specific memory components highly important for daily life. Prospective memory refers to the performance of an intended action at a particular point in the future, e.g. keeping an appointment or giving a message to a colleague when seeing him next time at work or so. Source memory comprises all information about where and when an event took place and how information was acquired. Detailed source information causes events to become vivid and rich and therefore represents a crucial quality of human memory. Just imagine your wedding. How would the afterglow be without all the memories around your wedding such as the weather at this day or the whole atmosphere? In our studies, we found that in particular planning deficits and inhibitory deficits were responsible for impaired prospective memory and source memory of adults with ADHD.
In conclusion, our studies demonstrated that adults with ADHD have not only problems in attention and executive functions but they do also suffer from considerable impairments in several aspects of memory which are crucial for everyday life. However, memory impairments are not caused by an increased forgetfulness but are rather associated with executive dysfunctions (such as deficits in planning and inhibition). In the light of these results, we believe that the detrimental effect of executive dysfunctions on memory is so important that it should be considered in behavioral based interventions which focus on planning as well as structuring and organizing information. Hence, memory functioning of adults with ADHD might be markedly improved by treating disorganization and planning deficits.
Relevant Publications and Links
Fuermaier, A.B.M., Tucha, L., Koerts, J., Aschenbrenner, S., Weisbrod, M., Lange, K.W., & Tucha, O. (2013a). Source discrimination in adults with attention deficit hyperactivity disorder. PLoS ONE, 8(5), e65134.
Fuermaier, A.B.M., Tucha, L., Koerts, J., Aschenbrenner, S., Westermann, C., Weisbrod, M., Lange, K.W., & Tucha, O. (2013b). Complex prospective memory in adult patients with attention deficit hyperactivity disorder. PLoS ONE, 8(3), e58338.