Anhedonia is a symptom defined by the subjective decrease in the ability to experience pleasure, especially when compared to similar experiences that were perceived as pleasurable in the past. Anhedonia is a common symptom of depression as well as other mental health disorders. Overall, anhedonia remains a difficult symptom to treat, and first-line drug therapies are not always sufficient to correct it.

What is it ?

Anhedonia is a symptom defined by the subjective decrease in the ability to feel pleasure, especially when compared to similar experiences that were perceived as pleasant in the past. It is the French psychologist Théodule Ribot who created, in 1896, the neologism “anhédonie” from the Greek “a”, “without” and “hêdonê”, “pleasure”. It is a common symptom of depression as well as other mental health disorders.

Anhedonia is a progressive symptom. It depends on the notion of pleasure, which includes many categories and different degrees, which can be described and quantified. Thus, like the concept of pleasure, anhedonia can manifest itself in several ways:

• Physical anhedonia refers to a decrease in the ability to experience pleasure when engaging in physical activities such as eating, touching, and having sex;
• Social anhedonia refers to a decrease in the ability to experience pleasure in interactions with other living things such as talking and connecting with friends and family.

However, the concept of pleasure is complex and incorporates, in addition to the subjectivity of the pleasure experienced, distinct components: positive reinforcement, desire and motivation, cognitive ability to anticipate the usefulness of a behavior, reward processing and memory of the behavior. experienced with pleasure. These new data recently led to the specification of two new categories of anhedonia:

• Consumption anhedonia or consuming anhedonia – appreciating what you do;
• Motivational anhedonia or anticipatory anhedonia – wanting to do.

How to recognize anhedonia

The first symptoms of anhedonia to appear are often:

• The characteristic indifference of patients to social interactions;
• The absence of emotion;
• The extinction of affection for family and friends;
• Loss of satisfaction in various activities.

To diagnose anhedonia, two criteria must be met:

• The person declares a decrease in pleasure during the practice of certain activities, physical and / or social;
• The person has experienced pleasure, or more pleasure than now, from these activities.

When other mental or physical symptoms are present, anhedonia can be conceptualized as a pathological symptom of the primary condition, similar to depression or schizophrenia.

Risk factors

The risk factors that can cause anhedonia are the following:

• The Depression ;
• Schizophrenia ;
• Substance dependence (drug addicts);
• Anxiety;
• Suicide-related events;
• Post-traumatic stress disorder;
• Autism spectrum disorder;
• Parkinson’s disease ;
• Strokes;
• Certain chronic diseases.

Alteration of reward and pleasure circuits

Advances in neuroscience have revolutionized our understanding of the processes linked to the reward and pleasure circuits. Currently, the clinico-biological construct of anhedonia is closely related to the concepts of reward assessment, decision making, anticipation and motivation. These different cognitive processes are underpinned by neural circuits mainly located at the level of the ventral striatum and the prefrontal cortical regions.

Alteration of the dopaminergic system

On the brain level, researchers believe the condition is due to an alteration in the dopaminergic system, the mechanism by which dopamine – a chemical found in the brain – produces feelings of pleasure and satisfaction. Altered, this system would then no longer be able to produce pleasure, satisfaction and well-being in situations such as depression, schizophrenia and the withdrawal period for drug addicts.

Different neurological pathways involved

The preclinical literature describes the relationship between consuming anhedonia and motivational anhedonia as “taste” and “desire”, respectively. The preclinical literature also suggests that these different aspects of pleasure involve different neurobiological pathways. Drug anhedonia, which refers to “taste” deficits, likely involves changes in opioid function. Motivational anhedonia, on the other hand, which refers to the “deficiency” of craving, likely involves changes in dopamine function. Future research should determine how the nature of anhedonia differs, or does not, from one disease setting to another.

Complex physiological processes

A 2005 study demonstrated that people with anhedonia had cerebral blood flow patterns similar to controls in response to aversive stimuli, but different from controls in response to enriching stimuli. Such studies add to the theoretical development of anhedonia, supporting the idea that anhedonia refers to a specific deficit in the ability to experience pleasure and does not necessarily affect the ability to experience pain or sadness. .

Drug treatments

In the case of loss of sexual desire, anhedonia can be caused by taking certain antidepressants or by treatments for schizophrenia – antipsychotics – and other drugs – such as benzodiazepines and stimulants.

Loss of positive emotions

Anhedonia is not always a black-and-white problem. Although the patient may still enjoy eating chocolate ice cream or listening to jazz, he or she will no longer experience the same joy or the same positive emotions while practicing these activities, without being able to explain it to himself.

Social isolation

Anhedonia makes relationships, including those with friends and family, difficult and can lead to isolation and social anxiety. Once the reward for fun wears off, it’s hard to motivate yourself to spend time with others. Relationships thrive on positive feedback too, and without it, they can wither.

Loss of libido

Anhedonia can cause a loss of libido and interfere with a romantic relationship.

Suicide

Anhedonia is considered a risk factor for suicide in patients with major affective disorders.

To treat anhedonia, of course, you have to look for the cause. It is therefore necessary to diagnose the disease causing the symptom such as depression, schizophrenia, certain personality disorders, post-traumatic stress syndrome or disorders inherent in substance use.

For situations where drug therapy appears to be the cause, anhedonia can be treated by changing the dose, stopping the offending drug, or changing the nature of the treatment.

With depression, people on antidepressants – selective serotonin reuptake inhibitors (SSRIs) – may find that anhedonia improves with the rest of their depression symptoms, but this is not always the case. Sometimes these drugs ease the emotions and make the problem worse.

Scientists are working on new treatments. Ketamine, a psychotropic drug used as a general anesthetic and antidepressant in the United States, appears to be a promising drug.

Overall, anhedonia remains a difficult symptom to treat, and first-line drug therapy is not always sufficient to correct it.

Some research is also looking at a treatment based on the restructuring of the cognitive distortion – reality distortion – caused by motivation anhedonia. This treatment involves behavioral and cognitive therapy. The goal is to help the person to identify the mechanisms at the origin of his problems and to adopt new behaviors in order to be able to gradually get out of his psychological suffering.

Finally, some tips can help reduce the symptom of anhedonia:

• Take walks in nature, in childhood places filled with happy memories;
• Respect your sleep, with nights of at least 8 hours,
• Adopt a healthy diet, especially fruits;
• Practice a sport regularly;
• And many more