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The Neuroscience of Psychiatric Medicine

Instruction manual for Clinical Psychologists part 2

brain neurotransmitters

The second part of this article encompasses the basics of how psychiatric medicine works. This is important for Psychologists and Therapists to know for various reasons but one important reason is for us to be able to clarify the doubts and queries that the patients/clients might have regarding psychiatric consultation and medication. 

When we talk about mental health issues, there are three basic neurotransmitters that play a part, namely: 

  1. Nor-Epinephrine 

  2. Serotonin 

  3. Dopamine 

The content below describes the role of these neurotransmitters in Psychiatry the basic mechanism of action of the medicines that affect these neurotransmitters 


What is it?

Norepinephrine, often known as noradrenaline (NE), is a hormone and a neurotransmitter. It is mostly produced in the adrenal glands and brainstem and is essential to the body's fight-or-flight reaction.


  • Arousal and awareness: Norepinephrine heightens awareness and prepares the body to react quickly to outside stimuli, facilitating prompt responses in high-stress scenarios.

  • Blood Pressure: Norepinephrine raises vascular resistance and constricts blood vessels, which aids in preserving steady blood pressure levels.

  • Sleep-Wake Cycle: Norepinephrine promotes wakefulness and decreases sleepiness, having a profound impact on the sleep-wake cycle.

  • Mood and Memory: Norepinephrine has a critical role in the regulation of mood and cognitive processes, as well as the development of memories.

Mental Health Disorders Involving Norepinephrine

  •  Depression: Prolonged sadness and a lack of interest in daily activities are two signs of depression that are linked to low norepinephrine levels.

  • Anxiety Disorders: Increased stress and anxiety are brought on by a dysregulation of norepinephrine, which can lead to panic attacks and generalised anxiety disorder.

  • Attention Deficit Hyperactivity Disorder (ADHD): The symptoms of ADHD are caused by insufficient norepinephrine activity, which interferes with impulse control and attention.

  • Post-Traumatic Stress Disorder (PTSD): Hyperarousal and heightened stress responses are associated with abnormal norepinephrine levels in PTSD.

  • Bipolar Disorder: The manic and depressed episodes that are typical of bipolar disorder can be attributed to fluctuations in norepinephrine levels.

 Medicines Targeting Norepinephrine Dysregulation

  • Antidepressants: 

  • Serotonin- Norepinephrine Reuptake Inhibitors, or SNRIs, are antidepressants that elevate serotonin and norepinephrine levels by blocking their reuptake, which elevates mood and emotional equilibrium.

  • Tricyclic antidepressants, or TCAs, are medications that also increase serotonin and norepinephrine's availability in the brain and lessen depressive symptoms by preventing their absorption.

  • Stimulants: 

  • Amphetamines: These medications improve alertness and focus while lowering the symptoms of ADHD by increasing the release of norepinephrine, dopamine, and other neurotransmitters.

  • Norepinephrine Reuptake Inhibitors: By preventing norepinephrine from being absorbed and keeping levels higher in the synaptic cleft, these drugs can help treat diseases including depression and ADHD by enhancing mood, energy, and focus.


What is it?

Serotonin, also known as 5-hydroxytryptamine (5-HT), is an essential monoamine hormone and neurotransmitter. It is mostly found in the central nervous system, blood platelets, and the gastrointestinal tract and is synthesised from the amino acid tryptophan. Serotonin is a neurotransmitter that influences a number of physiological and psychological processes by sending messages from nerve cells in the brain to other parts of the body. Because of its positive effects on happiness and well-being, it is frequently described as the body's natural "feel-good" chemical. It regulates mood, sleep, appetite, digestion, memory, and social behaviour.


  • Mood Regulation: Because of its favourable effects on happiness and well-being, serotonin—often referred to as the "feel-good" chemical—plays a crucial role in mood regulation and emotional stability.

  • Sleep: Melatonin, a hormone that controls the sleep-wake cycle, is produced only when serotonin is present, which affects the quality of sleep by regulating sleep cycles.

  •  Digestion: Serotonin plays a major role in hunger, digestion, and gut health by regulating bowel movements and function. Serotonin's quick release into the stomach causes nausea, which aids in the body's removal of toxic materials.

  • Sexual Desire: Serotonin is involved in sexual function and desire, influencing libido and sexual behavior.

Mental Health Disorders Involving Serotonin

  • Depression: Dysregulation of Serotonin in the body can lead to several negative consequences, a few of which include loss of interest in daily activities, sleep dysregulation and anhedonia, all of which are symptoms of depression 

  • Anxiety: Problems in the secretion, production and uptake of serotonin can lead to feelings of excessive worry and fear which are hallmarks of anxiety 

  •  Obsessive-Compulsive Disorder (OCD): Repetitive Behavious and obsessive thoughts are the primary characteristics of OCD which are known to have been influenced by the levels of Serotonin

  •  Post-Traumatic Stress Disorder (PTSD): Serotonin significantly affects an individual’s response to stress and their capacity of emotional regulation. Disturbed stress tolerance and emotional Dysregulation are important symptoms that are observed in PTSD 

  •  Panic Disorders: Severe anxiety episodes and panic attacks can be triggered by dysregulated levels of serotonin. 

  •  Sleep Disorders: Serotonin levels directly affect sleep patterns, influencing conditions like insomnia.

  •  Schizophrenia: The complex symptoms of schizophrenia, such as hallucinations and cognitive abnormalities, may be exacerbated by serotonin dysregulation.

  •  Phobias: Serotonin abnormalities have been connected to phobias and severe, illogical anxieties.

 Medications Targeting Serotonin Dysregulation

  • Selective Serotonin Reuptake Inhibitors (SSRIs): Drugs, like paroxetine, function by selectively preventing serotonin from being reabsorbed in the brain. This increases the amount of serotonin that is available to nerve cells and helps lessen the feelings of anxiety, depression, and other mood disorders.

  • Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs): This class of drugs includes venlafaxine, which targets serotonin in addition to blocking norepinephrine's reuptake, another neurotransmitter important in mood regulation. Serotonin and norepinephrine reuptake inhibitors (SNRIs) can affect mood and emotional stability more broadly by preventing their reuptake.

  • Tricyclic Antidepressants (TCAs): One example of a TCA is amitriptyline, which acts by preventing serotonin and norepinephrine from being reabsorbed. Even though TCAs are an older class of antidepressants, they are nevertheless given when SNRIs and SSRIs are poorly tolerated or ineffective. They may be especially helpful for chronic pain disorders and some forms of depression.

  •  Monoamine Oxidase Inhibitors (MAOIs):  MAOIs, for example, phenelzine works by preventing the breakdown of neurotransmitters such as dopamine, norepinephrine, and serotonin by the enzyme monoamine oxidase. The brain's levels of these neurotransmitters are increased by MAOIs by inhibiting this enzyme, which might elevate mood and lessen depressive symptoms. However, MAOIs are less frequently used as first-line therapies since they have dietary limitations and can interact with specific foods and drugs.


What is it?

Dopamine functions as a complex chemical messenger in the brain, playing a role in a number of physiological and psychological functions. Its roles in controlling locomotion, motivation, and reward experiences go much beyond pleasure. Dopamine affects coordination and voluntary movement by modulating motor control within the intricate neuronal circuitry of the brain. It also coordinates the complex interactions between emotions and is essential to the brain's reward system, which mediates pleasurable experiences and promotes motivated actions. The complex behaviours of this neurotransmitter highlight its importance in influencing not only our motor behaviours but also our affective states and intrinsic motivations.


  • Movement regulation: Dopamine plays a critical role in voluntary movement regulation by promoting communication amongst the many brain areas engaged in motor control. Dopamine, which is produced in the substantia nigra, aids in motor coordination and ensures precise performance. Dopamine's importance in motor function is highlighted by the fact that dysfunction in dopaminergic pathways can result in movement disorders such as Parkinson's disease, which is characterised by tremors and rigidity.

  •  Regulating emotions: Emotion regulation: Dopamine affects the reward system in the brain, which includes the prefrontal cortex and nucleus accumbens, to regulate emotions. In reaction to pleasurable stimuli, it elicits pleasure and motivation, driving actions intended to reap rewards. Dopamine signalling dysregulation is linked to mood disorders such major depressive disorder and bipolar disorder, highlighting the significance of dopamine in emotional regulation.

  • Regulating pleasure and reward: Dopamine acts as a mediator between reward and pleasure experiences, strengthening actions linked to pleasurable stimuli. Dopamine is released in reaction to positive experiences and encourages people to look for similar experiences in the future. Its participation in reward pathways affects anticipatory and gratification-driven learning, memory, and decision-making processes.

Mental Health Disorders Involving Dopamine

  • Depression: Depressive symptoms, including low motivation, diminished enjoyment from activities, and hopelessness, are associated with low dopamine levels.

  • Schizophrenia: A severe mental illness marked by delusions, disorganised thought patterns, and hallucinations, is thought to be caused by dysregulation of dopamine.

  • Addiction: Dysregulation of dopamine signalling is involved in addiction to substances like heroin, alcohol, and nicotine. Dopamine is a key component of the brain's reward system.

 Medications Targeting Serotonin Dysregulation

  • Antipsychotics: These drugs are widely used to treat psychotic diseases such as schizophrenia. They lessen psychotic symptoms including delusions and hallucinations by inhibiting dopamine receptors in the brain. Antipsychotics assist control neurotransmitter levels and restore equilibrium in those suffering from psychosis by inhibiting dopamine action.

  •  Antidepressants: By raising dopamine and norepinephrine levels in the brain, certain antidepressants, such as bupropion, are used to reduce the symptoms of depression. Bupropion increases the availability of these neurotransmitters by blocking their reuptake, which may help people with depression feel better and regain emotional equilibrium.

  • Dopamine agonists: These drugs mimic the actions of dopamine in the brain and are used to treat a number of ailments, such as Parkinson's disease, restless legs syndrome, and some forms of Parkinson's

This article is part of a series of instruction manuals for psychologists compiled by Team CINQ.IN. We will be regularly posting articles on various topics to support psychologists working in clinical settings.

About CINQ.IN: We provide evidence-based therapy for anxiety, depression, and more. We offer therapy and counselling services in Baner, Pune. For more information, contact us at +91 8009105005 / 8007566553.

  • Article by : Bharvi Ratanghayra

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