The mind (thoughts, feelings, actions, memory, , learning,  consciousness and other activities) functions by means of electrochemical impulses produced in the brain through the activity of neurotransmitters.

Disorders of thinking and behavior are biologically-based disorders of the brain . Abnormal behaviour stems from chemical imbalances in the brain. You cannot overcome them through "will power". They are not related to a person's "character". Like Diabetes is a disorder of the pancreas interfering with sugar metabolism, imbalance in body and brain chemistry interferes with mental health and influences how we behave.

What is Neuro-Behavioural medicine?

Neuro-behavioral medicine applies the principles of neuro-science to diagnosis, treatment (including case management) and prevention of behavioral, cognitive, and emotional disorders known to, or suspected to be due to disorder, disease, injury, or dysfunction of the brain.

A simple amino acid Tyrosine (found in soya, chicken, turkey, fish, peanuts, almonds, avocados, milk, cheese, curd / yoghurt, panneer / cottage cheese, lima beans, pumpkin seeds, and sesame seeds) is used, in our bodies,  to synthesize two very powerful chemicalsDopamine and Noradrenaline that can change the destiny of a human being by influencing circuits in the brain that control emotions and thinking. These neurotransmitters can decide whether the person becomes a peaceful, pleasure loving person or a violent, fear-generating terrorist.

Neurotransmitters are the chemicals which allow the transmission of signals from one neuron (brain cell) to the next across synapses (connections). They are produced by some glands such as the pituitary and the adrenal glands. Neurotransmitters are involved in thinking, feeling and action. In short neurotransmitters control the mind.

There are more than 40 identified Neurotransmitters. Here we shall see how the most common neurotransmitters act on the mind.

Acetylcholine

In the brain , acetylcholine and the associated neurons form  the cholinergic system, which tends to cause excitatory actions. Stimulation of acetylcholine receptors in the brain by nicotine from tobacco and arecoline from betal nuts causes addiction to these substances. Damage to the cholinergic (acetylcholine-producing) system results in memory deficits associated with Alzheimer's disease

Noradrenaline

Our nervous system is brought into a state of "high alertness by Noradrenaline.  The adrenal glands release it into the blood stream, along with adrenalin.  It is also important for forming memories. Noradrenaline along with dopamine, plays a large role in attention and focus.

As a stress hormone, Noradrenaline affects parts of the brain responsible for attention and responding actions. Along with adrenaline, nit underlies the fight-or-flight response. Stress tends to deplete our store of adrenalin, while exercise tends to increase it.  Street drugs such as Amphetamines work by releasing noradrenaline, as well as other neurotransmitters like dopamine and seratonin.

Disturbances in the noadrenaline system can cause depression.

Serotonin

Serotonin is an inhibitory neurotransmitter that is intimately involved in emotion and mood. It has various functions, including the regulation of mood, appetite, sleep, muscle contraction, and some cognitive functions including memory and learning.

Insufficient availability of serotonin can result in:

• depression
• problems with anger control
• obsessive-compulsive disorder
• suicide
• increased appetite for carbohydrates (starchy foods)
• trouble sleeping

Low levels of serotonin may also be associated with intense spiritual experiences. Extremely high levels of serotonin can have toxic and potentially fatal effects, causing a condition known as serotonin syndrome. It can also cause migraines, irritable bowel syndrome, and fibromyalgia.

Dopamine

Dopamine  is an inhibitory neurotransmitter that blocks the functioning of neurons.  

Dopamine has many functions in the brain, including important roles in behavior and cognition, motivation, punishment and reward, sexual gratification, sleep, mood, attention, working memory, and learning.

It is strongly associated with reward mechanisms in the brain providing feelings of enjoyment and reinforcement.  Dopamine is released by naturally rewarding experiences such as food, sex, drugs, and neutral stimuli that become associated with them. Recent studies indicate that aggresssion may also stimulate the release of dopamine. Drugs like cocaine, opium, heroin, and alcohol increase the levels of dopamine, as does nicotine.  If it feels good, dopamine neurons are probably involved!

Psychosis has been shown to involve excessive amounts of dopamine in the frontal lobes of the brain responsible for information processing. 

Reduced dopamine concentrations in this region of the brain can cause a decline in memory, attention, and problem solving and causing attention deficit disorder (ADHD). 

Reduced dopamine activity reduces motivation, and cause  inability to experience pleasure. 

Low dopamine may related  also to social anxiety. 

Dopamine plays a role in pain processing with low levels of dopamine  associated with chronic pain.

Dopamine increases  arousal and goal directed behaviors and decreases latent inhibition thereby increasing the creative drive.

Endorphins

Endorphin is short for "endogenous morphine."  It is similar to morphine in structure and has similar functions.

Endorphins are produced during long, continuous moderate and high intensity workouts, when breathing becomes difficult. They are also released during excitement, pain, consumption of spicy food and orgasm, and they resemble the opiates in their abilities to dull pain and produce a feeling of well-being.

Endorphins work as "natural pain relievers." and "pleasure producers". The opioid drugs work by attaching to endorphin's receptor sites. 

Profound relaxation triggers the production of endorphins.

GABA

GABA acts like a brake to the excitatory neurotransmitters that lead to anxiety.  People with too little GABA tend to suffer from anxiety disorders.

If GABA is lacking in certain parts of the brain, epilepsy results.

Glutamate

Glutamate is the most common neurotransmitter in the central nervous system - as much as half of all neurons in the brain - and is especially important in regards to memory.  Glutamate is also toxic to neurons, and an excess will kill them.  Sometimes brain damage or a stroke will lead to an excess of Glutamate resulting in death of  many more brain cells than from the original trauma. 

Glutamate occurs as part of the ischemic cascade (due to decreased blood supply to the brain) and is associated with stroke and diseases autism, some forms of mental retardation and Alzheimer's disease.

Glutamate has been implicated in epileptic seizures.

As your grandmother may have told you, a glass of warm milk  helps you to sleep.  In fact a little milk before bedtime increases the levels of serotonin. Serotonin is a derivative of tryptophan, which is found in milk.