Since feeding is the least complex, this will be discussed first. A hierarchy of modulation centers that were determined by evolution determines normal feeding, like other functions. This hierarchy possesses multiple opposing stimulatory and inhibitory pathways. The location of all of the modulating centers and pathways is partially unknown. We can presume the lower level systems are in the hypothalamus and brain stem, with the hierarchy extending to the limbic system, para limbic areas and then to the cortex. Specific food preferences are determined by recognizing the need for specific nutrients.

Normal feeding is begun by feeding arousal, called appetite, at lower levels of arousal while hunger begins at higher levels of arousal. The stimulation of this sensory pathway then impacts modulation, which alters attention, processing and behavior in the direction of food-seeking behavior. The greater the hunger, the greater the extent that mental resources are shifted towards food-seeking behavior.

After food is consumed, satiation signals serve as a negative feedback loop to stop eating behavior. In individuals with no eating disorder, appetite and satiation control eating behavior. In short, signals from the viscera and lower powers control both starting and stopping. In other words, normal eating is predominantly controlled by signals, which we perceive as "from the stomach".

Other signals also impact feeding. One is the need for pleasure. When sources of pleasure are blocked, food becomes a disproportionate source of gratification. Excessive eating then overrides the normal satiation signals.

Another motivation is driven by the drug effect of the food. Food is both a nutrient and a psychoactive drug. Some foods have more of this drug effect than others, i.e.: alcohol, chocolate, sugar and caffeine. The craving drives some overeating for these drug effects.

There are also a group of psychologically driven motivators for feeding. For example, individuals with PTSD and a significant degree of repressed memory often feel emotionally empty as a result of emotional repression. When this occurs, there is a strong motivation to eat to "feel full". The stomach fullness is an effort to relieve a feeling of emotional emptiness. There are also many learned associations with eating or with specific foods which may override the basic appetite-satiation pathway.

Positive and negative social feedback, in turn, effects another group of pathways involving social stature or dominance. When we receive a comparatively high ratio of positive social feedback, self-esteem is generally higher and the social correlate of social status is also high. Conversely, a comparatively high ratio of negative social feedback is generally correlated with low self-esteem and low social stature. Individuals who feel little or no shame from negative social feedback are either asocial or antisocial. Conversely, individuals who experience excessively high levels of shame in response to negative social feedback can often become shame-phobic, which is more commonly called social phobia. Individuals with high self-esteem (the internal mental perception) and high social status may, in turn, display more social dominance. Social dominance is the concept that those, which are recognized in a more positive light, have more social power; their needs carry more significance than those who are perceived to be lower on the social hierarchy. Social dominance is, therefore, equated with an imbalance of social power. Greed is the pursuit of ones needs regardless of the needs of others. Greed increases when there is an imbalance of social power.

Deception is a part of nature. Interpersonal deception may be employed in an effort to enhance social acceptance and social power. There are probably a group of neural circuits, which facilitate deception.

Deception detection (suspicion, mistrust and, when extreme, paranoia) allows us to detect interpersonal deception. The emotional learning of interpersonal trust vs. mistrust is critical to further develop this capability. PTSD from interpersonal trauma results in difficulties with trust vs. mistrust judgment. Lust is the motivation for sexual gratification. This results in motivation from sexual pursuit. Sensuality is the pursuant of pleasurable sensation. Lust and sensuality are often pursued simultaneously.

Emotional awareness is our ability to recognize emotional status. In others, or ourselves empathy is the concern for the emotional status of another person. Altruism is the pursuit of the well being of others.

Pair bonding (mates, often with a sexual bond) and family bonding are relationships in which there is normally a significant level of empathy and altruism. Nurturance, the process of attempting to meet the needs of others (feeding, grooming etc.), is seen in parenting and courtship rituals.

Strong mate bonding is a foundation for family bonding. Before discussing mate bonding, let us first discuss gender. There are obvious differences between male and female functioning. Somehow, these can be reduced to differences in brain circuits, neural functioning, hormonal functioning etc. Gender determines difference in perception, processing, modulation and motor functioning. When we compare a large number of females to males, what differences are generally seen? Compared to males, females generally have a better sense of smell, are more perceptual, more emotionally perceptive of other's emotions, are more concerned with social acceptance, are more emotionally expressive and display more facial expressiveness. Compared to females, males modulate more towards motor rather than perceptual functioning, are more concerned with social status and control of their environment and are more visual. PET scans show considerable differences between men and women as different parts of the brain are activated while solving the same problem. What are the details of the neurochemistry that differentiates male and female functioning?

Male sexual arousal is more associated with aggressive arousal. Therefore, comfort with aggression and the development of appropriate expressions of positive aggression towards others is critical in the development of male sexual functioning.

Female sexual arousal is more associated with being the recipient of positive aggression from others. As a result, a well-developed capacity for trust assessment is critical in the development of comfort and confidence in female sexual functioning.

Attraction between two people, although opposite in some ways, has many similarities to the adversive pathways that impact interpersonal behavior. Why are we attracted to some people and repelled from others? This is determined by a combination of instinct, learning and perceiving a person's emotional status. We are attracted to others and subsequently love others who are perceived to meet our needs. All of us have different needs-sexual gratification, companionship, commitment, responsiveness, trust, respect, nurturance etc., and prioritize these and other needs in different ways. Unlike the expression "opposites attract", we are instead drawn to people who share similar values, goals, temperaments and problem solving approaches. A normal part of courtship rituals consists of reciprocal nurturance activities, which strengthen the bond between two people. Male arousal and attractiveness is generally associated with aggressive behavior and inhibited by fear. Conversely, female arousal and attractiveness is generally inhibited by aggressiveness but not inhibited by fear.¹⁰

With the development of interpersonal bonding, there are also adversive emotional reactions directed towards any others who are perceived as a threat to this bond. For example, pair bonding is associated with increases of both prolactin and arginine vasopressin, which enhances the positive bond between the two. At the same time, negative reactivity is increased toward anyone who would be a threat to the bond (the emotion of jealousy).

Nursing mothers have a high level of oxytoxin and prolactin, which enhances the nurturing relationship with the child while also enhancing a negative reaction toward others who may be a threat to this relationship.

While bonding is the formation of a bond, conversely, grief is the breaking of a bond. Grief is a normal, healthy process that allows us to emotionally disconnect from someone who is no longer emotionally accessible to us. Grief may occur when a relationship with someone ends or when we are adapting to a disappointment in our perception or imagination of that relationship.

Interpersonal abuse may occur in many forms. Most commonly, we see a high level of greed, deception, a lack of empathy and an imbalance of social power. All abuse has some common denominators. For example, the individual performing the abuse attempts to enhance their position of power, undermining the self-esteem of the proposed victim. This is accomplished by approaching the intended victim in some manner, which impairs their confidence, self-esteem and/or judgment. The perpetrator initiates some behavior that evokes a strong emotional reaction that is maladaptive, impairing the judgment of the victim. For example, the perpetrator attempts to induce shame, fear, greed, lust, revenge, anger or any other emotion, which may impair the victim's judgment. Once judgment is impaired, there is an imbalance of social power and the perpetrator pursues an interaction that is unfair to the intended victim.

Extreme abuses of power cause a pathological vicious cycle that is more appropriately called violence. Violence is a complex problem with multiple causes and deterrents. Common problems associated with violence include social system failures, a failure to form strong interpersonal bonds, substance use, a perception that others are very threatening, neurological impairments and limited coping skills. A commonly seen pattern is the combination of neurological impairments and a history of abusive relationships. In many violent situations, the perpetrator views the victim as a threat in some manner and acts defensively in an aggressive manner. Sometimes the threat is purely psychological or imaginary.

Predatory aggression, which is more difficult to understand, occurs when the perpetrator seeks out a victim. These individuals often describe a strong motivation to dominate another person. In these cases, the aggressive act gives the perpetrator a feeling of power in compensation for a more pervasive feeling of powerlessness.

The physiology of aggression is controlled by a hierarchy of mental centers, not all of which are well understood. Violence is more commonly associated with an underactivity of inhibitory centers but is occasionally associated with an overactivity of stimulatory centers. On a neurochemical level, low serotonin is associated with violence both to the self and to others.

A recent National Comorbidity study showed that the lifetime incidence of a mental disorder in our society is 48%, meaning that one in two people meet the criteria for having a mental disorder at some point in their lives. What is the total impact of this in our society?

Insight into our behavior helps to improve the quality of our lives. Anxiety/fear disorder, depression, substance abuse and personality disorders are common conditions that extract a great indirect cost upon society. Developmental and psychotic disorders also extract huge expenses as a result of their association with lifetime disabilities. The common everyday problems of anxiety, depression and substance abuse extract a great cost upon our society on a daily basis.

Anxiety as well as many other mental and physical disorders creates chronic stress which evolves into depression with time. The incidence of depression keeps rising. A recent study demonstrated that depression costs forty three billion dollars per year. Although the cost of treatment is a small fraction of this total, the greatest cost is in the loss of productivity and the loss of lives through suicides.

What we call anxiety disorders are really fear disorders. These include social phobia, most obsessive-compulsive disorders, panic disorder, posttraumatic stress disorder, generalized anxiety, hypochondrias and psychosomatic disorders. As previously discussed, the common denominator of this group of disorders is a dysregulation of the harm avoidance pathways. When we are in a fearful state and do not know how to respond to perceived threat(s), the end result is anxiety. We live in a highly complex society in which it is difficult to identify and effectively respond to threats. Our fear responsiveness, molded by genetics and evolution, is limited in its adaptive capabilities. Although carefully selected individuals can survive in space capsules or in crowded nuclear submarines under polar ice caps for extended periods, not all of us can adapt to our current environment. Being a passenger in a commercial airplane feels unnatural to some of us and we can not always overcome this instinctually based fear. Many typical situations evoke anxiety because they feel unnatural such as assembly line work, mid-management stress, the anonymity of our society and the lack of control over our own lives. Technology has advanced faster than our capacity to adapt those changes to the reality of our human nature. The end result is a massive epidemic of anxiety in which we feel an inadequate level of control over our lives.

Anxiety, Depression and Anhedonia contribute to the large epidemic of substance abuse. Why aren't they feeling good from life? People who are mentally healthy are not drawn to abuse substance to become high or to "feel good".

It is difficult to calculate the total cost from problems caused by tobacco, alcohol, cocaine, marijuana, opioids and all the other types of substances abused. This epidemic is particularly dangerous since it affects our youth. In our society, it is difficult to make the transition from childhood to adulthood. As a result, we see excessively high statistics in adolescents who demonstrate this stress through drug abuse, alcoholism, teen pregnancy, runaways, incidence of mental illness, suicide, suicide attempts, accidents and homicides. The substances available to our youth today are far more lethal, more numerous and more affordable than we have previously seen.

We can now understand and effectively treat these conditions. If we turn our backs on the need for mental health education, research and care, we will be committing a serious crime against humanity.