Motivation and emotion/Book/2023/SSRIs and motivation

Overview

Figure 1. Venlafaxine is a SNRI (Serotonin and Norepinephrine Reuptake Inhibitor) used to treat depression (Suwala et al., 2019).

Case study

To examine the many problems of SSRI effects on motivation, here is a scenario identifying core issues surrounding SSRI usage. Patient 1 was placed on an SSRI antidepressant labelled mirtazapine, which caused symptoms of apathy and decreased initiative. Once the symptoms had been discussed with the consulting doctor, the patient was transitioned to an SNRI called venlaxafine. After four weeks of gradual increase in dosage, the patient showed a subsequent increase in motivation and emotional state (Salo et al., 2020).

Then, consider another case where patient 2, much like the first, described feeling emotionally flat and without motivation at the start of their SSRI treatment. However, ongoing treatment using venlafaxine showed gradual improvement in their mood and motivation once the dosage was increased and maintained (Salo et al., 2020).

Focus questions

What do the theories suggest about SSRI and motivation?
How do neurotransmitters affect motivation?
What are the effects of SSRIs' on motivation?[improve clarity]
How does motivation change with acute and chronic SSRI use?

What is the theory behind SSRIs?

Figure 2. Antidepressants have been shown to enhance neural connections and reduce stress-induced atrophy. (Normann et al., 2018)

Antidepressant theories rely on altering one's affinity towards adverse effects, maintaining neural networks to protect oneself from stress, and altering neurotransmitters to increase motivation. This section provides the theory of how SSRIs act as a protective barrier against neurodegenerative diseases such as anxiety and depression while boosting motivation.

Neurocognitive theory

Neurocognitive theory is the primary theory that explains pharmacological intervention on motivation and mental disorders. The theory combines biological and psychological approaches to explain antidepressant effects on the body (Godlewska, 2019). Furthermore, Godlewska (2019) explains that motivational and emotional deficits are essential for rehabilitation. For example, starting SSRI antidepressant medication leads to an immediate drop in motivation and a subsequent return to baseline levels. This theory proposes that this bias is due to one’s affinity towards experiencing more negative than positive effects. Godlewska and Harmer (2021) indicate antidepressant medication targets specific brain regions, such as the limbic system, to decrease negative bias to improve one’s mood and motivation. For example, decreasing negative views and stress will increase mood and motivation. This indicates that antidepressants change one's negative bias, directly reducing stress and allowing one to experience pleasure once harmful stimuli are removed.

Neuroplasticity theory

The second theory that seeks to explain SSRI intervention on motivation is its protective role against harmful stimuli such as stress and neurodegeneration. Firstly, it is stated that stress impacts motivation, as Yoshida et al. (2021) indicate distress deteriorates goal-directed behaviour. As such, SSRIs block stress from derailing motivational action by sustaining neural plasticity to maintain those neural pathways. This is important because stress plays a significant role in decreasing motivation due to atrophy. For example, regions such as the hippocampus, and amygdala have been implicated in shrinking due to chronic stress (Normann et al., 2018). Therefore, SSRIs protect the brain from atrophy while supporting neural pathways affected by mental disorders such as depression. However, de Oliveria et al. (2020) contradict this claim with their meta-analysis, showing that antidepressants as a stress-protective agency on hippocampal degeneration are somewhat controversial. Therefore, more analysis is needed to conclude SSRIs' efficacy in protecting the brain against stress and subsequent motivational deficits.

Monoamine theory

The final theory, monoamine theory, seeks to explain through a biological explanation of how antidepressants affect motivation. Firstly, as Khushboo et al. (2022) states, depression is caused by altered or lack of monoamines in the brain. Therefore, increasing monoamines to return an individual to healthy mental and motivational levels is the fundamental rule of antidepressants. Jiang et al. (2022) indicates monoamine theory relies on reduced (three) neurotransmitters that dictate emotions: dopamine (joy/reward), serotonin (happiness) & norepinephrine (fear/anger). Targeting these specific neurotransmitters can enhance motivation by increasing neurotransmitter activation. For example, lacking serotonin could lead one to have low happiness and mood which activities harder to perform. However, a problem that arises from this statement is the immediate onset of decreased motivation once the antidepressant intervention is initiated, as shown in the case study (Salo et al., 2020). Further sections below will strive to address this core issue.

Take Away Points

Emotional blunting acts as a negative effect suppressor
Antidepressants act as a defence against brain degeneration
Changing brain chemistry alters emotions and motivations

Choose your answers and click "Submit":

How do neurotransmitters impact motivation?

The problem with SSRI interventions is immediate drops in motivation despite increases in serotonin monoamines. This is important due to the fundamental role monoamines have in changing motivation. This section explores how SSRIs alter motivation by examining the role of two critical neurotransmitters needed for motivation.

Serotonin

Serotonin plays an essential role for motivation by regulating happiness and cognition. Roberts et al. (2020) identify serotonin to affect external factors such as reducing effort cost and stress, which negatively impacts motivation. Thus, serotonin seeks to boost motivation by lowering the cost of high effort tasks. An example of this can be seen within depression-prone individuals who experience heightened stress, increasing the effort needed to initiate a motivational behaviour. However, other studies combat this claim by studying the effects of high serotonin rats on motivation play. Siviy et al. (2011) identified serotonin to not increase play due to reduced effort cost; however, this may be due to the difference in brain structures between humans and rats.

Further studies have sought to understand the relationship between motivation and serotonin. Meyniel et al. (2016) identify serotonin to initiate behavioural motivation due to lowering the effort cost needed and not increasing incentive finding. This indicates serotonin does not increase motivation due to incentives such as conditioning effects but allows people to engage in activities by lowering the effort needed.

Dopamine

Figure 3. Dopamine is a neural transmitter essential for movement and experiencing pleasure/joy (Wise & Jordon, 2021).

The first [say what?] neurotransmitter that relates to SSRIs is dopamine’s role in initiating and maintaining behaviour. Wise and Jordan (2021) show dopamine as essential to maintaining motivation due to dopamine’s role in rewarding enjoyable behaviour. As such, dopamine conditions people to seek further stimuli to increase their enjoyment. Studies on brain areas and motivation identify the nucleus accumbens, ventral striatum, and the dorsal anterior cingulate as important regions for one to seek positive events to boost mood (Heron et al., 2018). Therefore, lowered brain activity in these areas is associated with decreased motivation. To support this claim, Voloh et al. (2021) have identified these brain regions, as well as disrupted communication to the prefrontal cortex, and executive control to be linked to apathy depletion symptoms in the form of depression. This shows that motivation will diminish when dopamine is not distributed to brain segments.

Take-away points

SSRIs flood the brain with serotonin to boost mood
Dopamine pathways are affected by altering serotonin
Movement is directly tied to emotions

The effects of SSRIs on motivation

Figure 4. Stress-induced atrophy causes the brain to misfire DA neurons, which leads to motivation deficits (Baik, 2020).

The research on SSRI effects on motivation indicates an immediate drop due to adverse side effects. Primary symptoms of SSRIs, such as emotional blunting, stress and sleep fluctuations, make antidepressants quick motivation blockers. This section discusses how the adverse side effects of SSRIs acutely reduce motivation and behaviour.

Emotional blunting onset

The first negative symptom of SSRI use is emotional blunting. As Christensen et al. (2023) states, emotional blunting is the inability to experience positive or negative emotions, leaving an person to feel detached. For example, someone who is depressed may not feel able to express any kind of emotion. Therefore, motivation is harder to initiate due to a lack of emotion prohibiting people from seeking a stimulus that will create further motivation. Christensen et al. (2023) support this claim by showing an inverse relationship between motivation and emotional blunting. As such, individuals who feel flat cannot show emotions and cannot seek pleasure or arousing stimuli. (Reeves, 2018) proposes that an immediate increase in serotonin has been linked to dopamine deficits due to borrowed neurotransmitter pathways. Therefore, immediate SSRI intervention lowers emotional and motivational levels upon starting the medication. However, more studies are needed to elaborate on this finding.

Stress fluctuations

The second motivational symptom that is affected by SSRI intervention is stress. As Balik, 2020 & Yoshida et al. 2021 state, stress negatively impacts dopamine by affecting the mesolimbic system; thus, lowering their pleasure and goal-directed behaviour. Without dopamine, it is harder to accomplish goals and acquire motivation. Kryst et al. (2022) found in their meta-analysis that fluoxetine reduced depression behaviours while inversely increasing anxiety-related symptoms. As such, hidden anxiety issues are not treated with SSRIs but suppressed. Contradictory to this conclusion, Jakubovski et al. (2019) stated in their meta-analysis that SSRIs performed positively for anxiety-related disorders. This shows controversial results on whether SSRIs increase or decrease underlying stress. Therefore, more research is needed to explore antidepressant medications for anxiety.

Reduced sleep

The third symptom that SSRIs impact are altered sleep patterns, which negatively impacts motivation. Studies on the effects of insomnia and its connection to motivation indicate a negative relationship (Wichniak et al., 2017). As a result, constant sleep depreviation[spelling?] becasuse of SSRIs will decrease motivation. which may explain apathy and anxiety-related symptoms. Quagliato et al. (2019) indicated in their meta-analysis that acute treatment of SSRIs gave individuals’ symptoms of fatigue, insomnia, and somnolence. As such, motivation is harder to initiate due to the onset of fatigue caused by SSRI use. Wichniak et al. (2017) explains this is due to a change in neurotransmitter levels such as serotonin, dopamine, and norepinephrine. This identifies the alteration caused by neurotransmitter by SSRI's as a cause for decreased motivation, particularly at high dose levels. Therefore, high doses will decrease motivation by causing symptoms of drowsiness and fatigue, making it harder to initiate behaviour as opposed to lower doses.

Take-away points

Emotional blunting will lower motivation or behaviour
Stress or anxiety negatively impact motivation
SSRIs cause insomnia and sleep problems, which lower motivation

What does the current literature say about SSRIs and motivation?

Figure 5. Fluoxetine (Prozac) is currently the most prescribed drug for mood disorders (Puścian et al., 2020)

The current antidepressant intervention for reducing anxiety and depression is the use of SSRIs. NIH MedlinePlus (2020) indicates that the most commonly prescribed SSRI antidepressants are Citalopram, Sertraline, Paroxetine, Escitalopram and lastly, Fluoxetine (Prozac), which are used to treat depression and motivation. This section evaluates the current literature on SSRIs to conclude their efficacy on motivation and to see if SSRIs can increase motivation.

Acute use of SSRIs on motivation

Antidepressant effects on motivation indicate an acute reduction in motivation. This is due to a monoamine fluctuation that negatively reduces one's motivational and emotional capacity. The current literature states that all antidepressants, including SSRIs, induce apathy. For example, Padala et al. (2020) identify in their study on apathy syndrome and SSRIs that 92% of their participants experienced a loss of motivation on SSRIs compared to a control sample without intervention. Furthermore, studies on AD usage and motivation in rats indicate that high acute doses reduce motivational play where rats were reluctant to seek high-effort tasks (Griesius et al., (2020). Thus, implicating acute high SSRI doses will lower motivational and pleasure-seeking behaviour while indicating an inverse relation between dopamine and serotonin due to SSRIs.

Chronic use of SSRIs on motivation

Unlike the research on acute SSRIs, long-term usage of SSRIs on motivation indicates a disparity in the efficacy of motivational increases. A meta-analysis on antidepressant intervention on anhedonia concluded that interests and activity seeking cannot be invoked with pharmacological intervention (Cao et al., 2019). Furthermore, it was identified that side effects such as sleep deprivation or insomnia need to be addressed before motivation is increased. This is supported by another study which examined that chronic fluoxetine impairs pleasure and reward behaviour (Puścian et al., 2021). This may explain why SSRI medications are changed during intervention to increase motivation (Sato et al., 2019). Studies by Evren (2021) and Fagiolini et al. (2021) identify a similar analysis with their studies, indicating that reduced side effects from initial medication intervention are important before motivational change can be achieved. However, the studies provided conflicting evidence on the efficacy of SSRIs on motivation, identifying that after eight weeks, adverse side effects were reduced, and subsequent motivation was increased. This indicates a disparity between reducing adverse side effects and initiating a individuals pleasure-seeking behaviour. However, it does conclude that motivation can be improved when individuals reduce or eliminate harmful side effects from SSRIs.

Increasing motivation with SSRIs

The controversial efficacy of SSRIs on motivation leads to whether motivation can be increased if the medication doesn't work. Ma et al. (2021) address this problem by illustrating that clinicians attempt to combat reduced emotional blunting with different dosage levels and antidepressant medication, indicating motivational deficits can be reversed by altering drugs. This is also supported by the case study where new medications can be used to reverse side effects.

Titration

The first form of motivational enhancement using SSRIs is known as titration, otherwise known as dosage adjustment. As Caffrey & Borrelli (2020) state, titration involves adjusting the dosage to reduce the adverse side effects of antidepressant medication. As such, motivation can be increased by reducing the adverse effects, which increase one's experience of negative effects. If you remember the case study, this was shown when the changed dosage removed side effects such as emotional blunting, which increased the patient's motivation. Torta (2012) identifies that antidepressant effects on motivation are person-dependent and not strictly drug-dependent. Therefore, tailoring to individuals and adjusting the dosage is essential to lower adverse side effects.

Switching medication

The second form of motivational enhancement is altering the medication to enhance motivation when titration is insufficient. As Keks et al. (2016) states, switching medications is an important process to reduce adverse side effects from the previous medication. This shows a complex system between SSRI use and the conflicting nature of effects on motivation. Keks et al. (2016) states the process involves gradually reducing the current antidepressant and introducing a new antidepressant to increase the success rate. As a result, switching to a new drug may decrease side effects and improve quality of life. This is supported by the case study, which identifies motivation can be increased with new pharmacological interventions when previous drugs were lowering motivation.

Take-away points

Motivation can be increased if side effects are addressed
More research is needed to reduce SSRI adverse effects
Motivational response to SSRIs is person dependent

Conclusion

SSRIs will negatively or positively affect motivation depending on various factors. Firstly, the theories behind antidepressants on motivation propose that SSRIs reduce side effects and protect neurons by changing neurotransmitters to boost mood and motivation. However, the efficacy of these theories needs to be examined further.

Secondly, the literature states that neurotransmitters are important for motivation, suggesting SSRIs alter serotonin and dopamine pathways. This is due to motivational factors such as effort cost and pleasure, which are changed due to altering neurotransmitters. However, the literature shows that the complexity of monoamine altering will induce adverse side effects, which needs more research. As shown, symptoms such as emotional blunting, reduced sleep, and increased stress are symptoms that negatively impact motivation.

The SSRI literature on motivation shows that immediate SSRI use will lower motivation due to increased emotional blunting, anxiety, and insomnia. The literature then indicates that long-term SSRI use by showing a varys[say what?] on its ability to boost motivation. This shows that more research is needed for long term SSRI use on motivation.

Lastly, factors such as type of SSRI, titration, and individual reactions to the SSRI are all factors that affect one’s affinity towards motivational change. Therefore, SSRIs will either increase or decrease motivation depending on the persons[grammar?] tolerance to SSRI side-effects.

References

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External links

2-Minute Neuroscience: Dopamine (Youtube.com)
Selective Serotonin Reuptake Inhibitors (Youtube.com)
What is Neuroplasticity? (Youtube.com)
Biology of depression (Wikipedia.com)
Why Antidepressants Make You Feel Worse (Youtube.com)