Research closely links attention deficit hyperactivity disorder (ADHD) and depression.1 While ADHD is overwhelmingly diagnosed in childhood, depression is thought to have a later onset and is typically identified in adolescence or adulthood. However, no matter when either condition is diagnosed, the right therapy and medication options can make a huge difference in how someone feels.
Signs of ADHD
ADHD features a pattern of inattention with or without hyperactivity that interferes with functioning or development. Typically identified in childhood, symptoms of ADHD need to be evident across multiple settings and with different caregivers for the diagnosis to be confirmed.2 While individuals with ADHD are often impacted throughout their lives, symptoms can be managed with behavior therapy and medication.
Although not specific to ADHD, children with ADHD can present with mild delays in language, motor, or social development.2 Criteria for ADHD are only met if the behavior under consideration occurs more frequently and is more impairing than it is in other individuals with the same developmental age.
Indications of ADHD include:3
- Sense of underachievement/low self-esteem
- Difficulty getting organized
- Chronic procrastination
- Trouble with follow-through on tasks
- Tendency to speak one’s mind, with little insight into the timing or appropriateness of the remark
- Frequent search for high stimulation
- Intolerance for boredom
- High distractibility
- Often creative, intuitive, and highly intelligent
- Difficulty following “proper” procedure
- Low tolerance for frustration
- Impulsivity
- Tendency to work endlessly
- Sense of insecurity or worry
- Mood swings
- Restlessness
- Risk for drug misuse and dependent behavior
Symptoms of ADHD
Symptoms of ADHD are first observed in childhood (i.e., before age 12). These children often display difficulties with persistence and focus in the face of challenging tasks (inattention), excessive motor activity (hyperactivity), and in thinking through the consequences of their actions (impulsivity). With regard to impulsive behaviors, individuals with ADHD are best described as having “ready, fire, aim” behaviors; they often act without thinking about the impact of their behaviors, thus demonstrating poor foresight and planning.
Symptoms of Depression
The core features of depression involve either depressed mood, loss of interest or pleasure in activities, or both for a period of at least 2 weeks.2 These features must be present for most of the day, nearly every day. It is common for either insomnia or fatigue to be the most obvious presenting feature of depression. Children and adolescents may have more obvious irritability than sadness.
Additional co-occurring symptoms of depression can include the following:
- Changes in appetite (either diminished interest or excessive eating)
- Periods of oversleeping
- Feelings of worthlessness or guilt
- Difficulty thinking/concentrating and trouble making decisions
Importantly, these episodes must cause severe distress or impairment in social, occupational, or adaptive functioning. Individuals experiencing more mild episodes of depression may demonstrate less of an impact on the daily functioning, but often report that day-to-day activities are more effortful. Depression can occur at any age, but the likelihood of being diagnosed with the disorder increases with entry to puberty.
These symptoms of depression can either be reported by the individual themselves or observed by those around them. In addition, these symptoms should reflect a change in the individual from the way they previously functioned (e.g., they should cause distress and impairment in one or more areas of daily life).2
The Connection Between ADHD & Depression
Several theories connect the diagnoses of ADHD with that of depression, ranging from problematic early-learning environments to shared neurobiology.4 These theories include how environment, genetics, and biological links connect ADHD and depression.
Environmental Links
Researchers have suggested that an ADHD diagnosis in childhood is linked to higher rates of environmental stressors that can have lasting impacts on the way individuals interpret events.1 Specifically, the lack of self-control attributed to individuals displaying symptoms of hyperactivity and impulsivity can lead to the perception that other negative experiences are out of one’s control (also known as an external locus of control), as well as demoralization and negative self-esteem. In other words, these early experiences may lead to negative thought patterns making an individual more susceptible to becoming depressed.
Additional early environmental factors that may serve as a link between ADHD and depression include family interactions and parenting practices.1 Due to the behavioral challenges that are common to children with ADHD, it is not uncommon for adults and/or caregivers to respond with negative, inconsistent, and at times coercive strategies. The unpredictable nature of these practices can lead to stressful interactions with adults and peers.4
Genetic Links
Studies of identical twins suggest that genetic factors are largely responsible for the co-occurrence of ADHD and depression.4 One study found that approximately 70% of the variance between the two disorders can be explained by genetic factors.5 One possible interpretation is that the same type of genetic predisposition could manifest as ADHD in childhood and then depression later on in life. This predisposition has been supported by recent research showing a causal effect of ADHD on major depression.4
Biological Effects
Magnetic resonance imaging (MRI) studies that have investigated the connection between brain biology and major depressive disorder have implicated a specific region of the brain: the hippocampus. Interestingly, the hippocampus is most directly linked to learning and the encoding and storing of memory. Other functions of the hippocampus include emotion regulation and social cognition.6 Researchers investigating this region of the brain in children with ADHD and depression found significantly reduced volume and connectivity.7 The experts concluded that neurobiological deficits associated with ADHD may increase the risk for depression.
Treatment of ADHD & Depression
Researchers suggest that the type of effective treatments to prevent and/or address depression in individuals with ADHD vary by the age of the patient.1 With the right therapy, and often medication, those with ADHD who are also experiencing depression can start to feel better.
Therapy
For younger children, behavioral parent training (BPT) may be the most useful way to improve long-term outcomes. BPT works primarily with caregivers to create consistent structure, supervision, and rewards for appropriate behavior. For older children with ADHD and depression, behavioral parenting interventions should be coupled with cognitive therapies to address both the environment and negative thinking styles that include perceived lack of control.
For adults, depression in the context of ADHD may be more treatment resistant, as these individuals are often more impaired.8 Specifically, the symptoms of ADHD (i.e., impulsivity, distractibility, and inability to focus) can interfere with treatment adherence, which may detract from successful outcomes.
However, key components of successful Cognitive Behavioral Therapy treatments for ADHD and/or depression are likely to benefit adults with comorbid conditions. These components include coaching on adaptive thinking, cognitive restructuring, and behavioral activation.8
Medication
While there have been effective established pharmacological interventions for either ADHD or depression, it is not fully clear how depressive disorders may impact the response of individuals with ADHD to stimulant medication.9 The results of one well-controlled study suggested that the combination of atomoxetine (Strattera) and fluoxetine (Prozac) was well tolerated by 173 patients, who showed improvement in both their ADHD and depressive symptoms.10
Statistics on ADHD & Depression
Attention-deficit/hyperactivity disorder is among the most common neurobehavioral disorders in children. ADHD affects an estimated 4%-12% of school-aged children worldwide.11 In addition, epidemiologically derived data suggest that up to 5% of college-aged students and adults meet criteria for ADHD.2
Major depressive disorder occurs in approximately 2% of children and 8% of adolescents. It has been estimated that the rate of depression in children with ADHD is approximately 5.5 times higher than that of children without ADHD, with rates ranging from 12%-50%.9 For adults, 16%-31% of those with ADHD are also likely to meet criteria for major depressive disorder.
How to Get Help for ADHD & Depression
Individuals diagnosed with ADHD, depression, or both often require the assistance of trained professionals to see meaningful improvement in their symptoms. It is common for friends or loved ones to be the first ones to identify the need for additional services; they can often spot ways that symptoms may be impacting daily functioning better than the affected individual themselves.
Primary care physicians (e.g., pediatricians, internists) can be extremely helpful in making referrals to specialists with expertise in presenting problems. Ultimately, licensed mental health providers such as psychiatrists or psychologists have the training to use evidence-based approaches to properly assess and provide treatment to improve symptoms.
Final Thoughts on ADHD & Depression
Both ADHD and depression can be chronic conditions that require substantial support. Small productive steps, taken one step at a time, are essential to ensure that struggles do not become overwhelming. Practicing self-care, including short-term goal setting and finding opportunities to laugh or interact with another person, can be extremely helpful during periods of high stress. Reaching out to healthcare providers can be an important and appropriate way to get started.
