Homesickness is the distress caused by being away from home. Its cognitive hallmark is preoccupying thoughts of home and attachment objects. Sufferers typically report a combination of depressive and anxious symptoms, withdrawn behavior and difficulty focusing on topics unrelated to home.

In its mild form, homesickness prompts the development of coping skills and motivates healthy attachment behaviors, such as renewing contact with loved ones. Indeed, nearly all people miss something about home when they are away, making homesickness a nearly universal experience. However, intense homesickness can be painful and debilitating.

Fortunately, prevention and treatment strategies exist for both children and adults. There are protective factors which can help people to cope with homesickness. Youth-serving organizations, such as the American Camp Association, have developed a homesickness prevention program. One study showed that this inexpensive intervention can lower the intensity of homesickness of first-year campers by an average 50%.

As an important side note when the elderly are moved, not of their own desire, into a nursing home and out of their own home they are more vulnerable to death due to the stress of homesickness. More studies are needed on this, however, the patient's dislike of the new nursing home seems to cancel out the care newly or better provided.

Whereas separation anxiety disorder is characterized by "inappropriate and excessive fear or anxiety concerning separation from those to whom the individual is attached" symptoms of homesickness are most prominent "after "a separation and include "both "depression "and" anxiety. In DSM terms, homesickness may be related to Separation Anxiety Disorder, but it is perhaps best categorized as either an Adjustment Disorder with mixed anxiety and depressed mood (309.28) or, for immigrants and foreign students as a V62.4, Acculturation Difficulty. As noted above, researchers use the following definition: "Homesickness is the distress or impairment caused by an actual or anticipated separation from home. Its cognitive hallmark is preoccupying thoughts of home and attachment objects." Recent pathogenic models support the possibility that homesickness reflects both insecure attachment and a variety of emotional and cognitive vulnerabilities, such as little previous experience away from home and negative attitudes about the novel environment.

The prevalence of homesickness varies greatly, depending on the population studied and the way homesickness is measured. One way to conceptualize homesickness prevalence is as a function of severity. Nearly all people miss something about home when they are away, so the absolute prevalence of homesickness is close to 100%, mostly in a mild form. Roughly 20% of university students and children at summer camp rate themselves at or above the midpoint on numerical rating scales of homesickness severity. And only 5–7% of students and campers report intense homesickness associated with severe symptoms of anxiety and depression. However, in adverse or painful environments, such as the hospital or the battlefield, intense homesickness is far more prevalent. In one study, 50% of children scored themselves at or above the midpoint on a numerical homesickness intensity scale (compared to 20% of children at summer camp). Soldiers report even more intense homesickness, sometimes to the point of suicidal misery. Naturally, aversive environmental elements, such as the trauma associated with war, exacerbate homesickness and other mental health problems.

In sum, homesickness is a normative pathology that can take on clinical relevance in its moderate and severe forms.

Culture shock is a subcategory of a more universal construct called transition shock. Transition shock is a state of loss and disorientation predicated by a change in one's familiar environment that requires adjustment. There are many symptoms of transition shock, including:

- Anger

- Boredom

- Compulsive eating/drinking/weight gain

- Desire for home and old friends

- Excessive concern over cleanliness

- Excessive sleep

- Feelings of helplessness and withdrawal

- Getting "stuck" on one thing

- Glazed stare

- Homesickness

- Hostility towards host nationals

- Impulsivity

- Irritability

- Mood swings

- Physiological stress reactions

- Stereotyping host nationals

- Suicidal or fatalistic thoughts

- Withdrawal

Culture shock is an experience a person may have when one moves to a cultural environment which is different from one's own; it is also the personal disorientation a person may feel when experiencing an unfamiliar way of life due to immigration or a visit to a new country, a move between social environments, or simply transition to another type of life. One of the most common causes of culture shock involves individuals in a foreign environment. Culture shock can be described as consisting of at least one of four distinct phases: honeymoon, negotiation, adjustment, and adaptation.

Common problems include: information overload, language barrier, generation gap, technology gap, skill interdependence, formulation dependency, homesickness (cultural), infinite regress (homesickness), boredom (job dependency), response ability (cultural skill set). There is no true way to entirely prevent culture shock, as individuals in any society are personally affected by cultural contrasts differently.

Paris syndrome (, , "Pari shōkōgun") is a transient mental disorder exhibited by some individuals when visiting or going on vacation to Paris, as a result of extreme shock derived from their discovery that Paris is not what they had expected it to be. The syndrome is characterized by a number of psychiatric symptoms such as acute delusional states, hallucinations, feelings of persecution (perceptions of being a victim of prejudice, aggression, or hostility from others), derealization, depersonalization, anxiety, and also psychosomatic manifestations such as dizziness, tachycardia, sweating, and others, such as vomiting. Similar syndromes include Jerusalem syndrome and Stendhal syndrome. The condition is commonly viewed as a severe form of culture shock. It is particularly noted among Japanese travelers.

Professor Hiroaki Ota, a Japanese psychiatrist working in France, is credited as the first person to diagnose the condition in 1986. However, later work by Youcef Mahmoudia, physician with the hospital Hôtel-Dieu de Paris, indicates that Paris syndrome is "a manifestation of psychopathology related to the voyage, rather than a syndrome of the traveller." He theorized that the excitement resulting from visiting Paris causes the heart to accelerate, causing giddiness and shortness of breath, which results in hallucinations in the manner similar to the Stendhal syndrome described by Italian psychiatrist Graziella Magherini in her book "La sindrome di Stendhal".

As with other anxiety disorders, children with SAD face more obstacles at school than those without anxiety disorders. Adjustment and relating school functioning have been found to be much more difficult for anxious children. In some severe forms of SAD, children may act disruptively in class or may refuse to attend school altogether. It is estimated that nearly 75% of children with SAD exhibit some form of school refusal behavior.

This is a serious problem because, as children fall further behind in coursework, it becomes increasingly difficult for them to return to school.

Short-term problems resulting from academic refusal include poor academic performance or decline in performance, alienation from peers, and conflict within the family.

Although school refusal behavior is common among children with SAD, it is important to note that school refusal behavior is sometimes linked to generalized anxiety disorder or possibly a mood disorder. That being said, a majority of children with separation anxiety disorder have school refusal as a symptom. Up to 80% of children who refuse school qualify for a diagnosis of separation anxiety disorder.

Just how SAD affects a child's attendance and participation in school, their avoidance behaviors stay with them as they grow and enter adulthood. Recently, "the effects of mental illness on workplace productivity have become a prominent concern on both the national and international fronts". In general, mental illness is a common health problem among working adults, 20 to 30% of adults will suffer from at least one psychiatric disorder. Mental illness is linked to decreased productivity, and with individuals diagnosed with SAD their levels at which they function decreases dramatically resulting in partial work-days, increase in number of total absences, and "holding back" when it comes to carrying out and completing tasks.

Disordered eating describes a variety of abnormal eating behaviors that, by themselves, do not warrant diagnosis of an eating disorder.

Disordered eating includes behaviors that are common features of eating disorders, such as:

- Chronic restrained eating.

- Compulsive eating.

- Binge eating, with associated loss of control.

- Self-induced vomiting.

Disordered eating also includes behaviors that are not characteristic of any eating disorder, such as:

- Irregular, chaotic eating patterns.

- Ignoring physical feelings of hunger and satiety (fullness).

- Use of diet pills.

- Emotional eating.

- Night eating.

- "Secretive food concocting": the consumption of embarrassing food combinations, such as mashed potatoes mixed with sandwich cookies. See also Food craving § Pregnancy and Nocturnal sleep-related eating disorder § Symptoms and behaviors.

Disordered eating can represent a change in eating patterns caused by other mental disorders (e.g. clinical depression), or by factors that are generally considered to be unrelated to mental disorders (e.g. extreme homesickness).

Certain factors among adolescents tend to be associated with disordered eating, including perceived pressure from parents and peers, nuclear family dynamic, body mass index, negative affect (mood), self-esteem, perfectionism, drug use, and participation in sports that focus on leanness. These factors are similar among boys and girls alike. However, the reported incidence rates of are consistently and significantly higher in female than male participants, with 61% of females and 28% of males reporting disordered eating behaviors in a study of over 1600 adolescents.