Animal hoarding is keeping a higher-than-usual number of animals as domestic pets without ability to properly house or care for them, while at the same time denying this inability. Compulsive hoarding can be characterized as a symptom of mental disorder rather than deliberate cruelty towards animals. Hoarders are deeply attached to their pets and find it extremely difficult to let the pets go. They typically cannot comprehend that they are harming their pets by failing to provide them with proper care. Hoarders tend to believe that they provide the right amount of care for them. The American Society for the Prevention of Cruelty to Animals provides a "Hoarding Prevention Team", which works with hoarders to help them attain a manageable and healthy number of pets.

In the United States, animal hoarders can be prosecuted under state animal cruelty laws for failing to provide a certain level of care to their animals. The following provides some examples of the standards currently in effect. In Alaska, the cruelty statute defines a minimum standard of care for animals that includes (1) food and water sufficient to maintain each animal in good health; (2) an environment compatible with protecting and maintaining the good health and safety of the animal; and (3) reasonable medical care at times and to the extent available and necessary to maintain the animal in good health. Likewise, in Colorado, a person commits cruelty to animals if he or she knowingly, recklessly, or with criminal negligence deprives an animal of necessary sustenance, neglects any animal, allows the animal to be housed in a manner that results in chronic or repeated serious physical harm, or fails to provide the animal with proper food, drink, or protection from the weather consistent with the species, breed, and type of animal involved. In Colorado's animal cruelty statute, “neglect” means failure to provide food, water, protection from the elements, or other care generally considered to be normal, usual, and accepted for an animal's health and well-being consistent with the species, breed, and type of animal.

Since failure to provide proper care for animals is an act of omission or neglect rather than an affirmative act, the failure to care for an animal is considered a misdemeanor offense in most states. For instance, in Alaska, if an animal owner fails to provide the aforementioned standards of care, the state has prima facie evidence of a failure to care for an animal. If the prosecutor can prove the owner’s failure to care for an animal was done with criminal negligence and the failure to care for the animal caused its death or severe physical pain or prolonged suffering, then the owner may be guilty of a Class A misdemeanor. In Colorado, failure to provide an animal with the proper standard of care is a Class 1 misdemeanor. In Virginia, each owner must provide for each of his companion animals: adequate feed; adequate water; adequate shelter that is properly cleaned; adequate space in the primary enclosure for the particular type of animal depending upon its age, size, species, and weight; adequate exercise; adequate care, treatment, and transportation; and veterinary care when needed to prevent suffering or disease transmission. Violation of these standards is a Class 4 misdemeanor. A second or subsequent violation may result in a higher grade misdemeanor. Likewise, under Virginia's animal cruelty statute, any person who deprives any animal of necessary food, drink, shelter or emergency veterinary treatment is guilty of a Class 1 misdemeanor.

However, some states, like California and New Hampshire, may provide felony provisions for depriving an animal of necessary sustenance, drink, and shelter. In Colorado, it is a class 6 felony upon a second or subsequent conviction of animal cruelty. In Maine, a person who is guilty of cruelty to animals may face criminal or civil charges at the discretion of the state’s attorney.

Not only are there significant health risks associated with compulsive hoarding, but scientists are also trying to pinpoint how significant the interference is with occupational and social functioning in a hoarder's daily life. In a pool of compulsive hoarders, 42% found their behavior problematic to the 63% of their family and friends who saw the behavior as problematic. The findings suggest that individuals who hoard may exhibit impaired sensitivity to their own and others’ emotions, and conversely, relate the world around them by forming attachments to possessions rather than to people. Lower emotional intelligence among hoarding patients may also impact their ability to discard and organize their possessions. With such detrimental characteristics, comprehensive research has been performed to find a cure. Although this is ongoing research, most investigations have found that only a third of patients who hoard show an adequate response to these medications and therapeutic interventions.

With the modifications to the DSM, insurance coverage for treatments will change as well as special education programs.

Obsessive-compulsive disorders are treated with various serotonergic antidepressants including the tricyclic antidepressant clomipramine and various SSRI medications. With existing drug therapy, OCD symptoms can be controlled, but not cured. Several of these compounds (including paroxetine, which has an FDA indication) have been tested successfully in conjunction with OCD hoarding.

Digital hoarding (also known as e-hoarding) is excessive acquisition and reluctance to delete electronic material no longer valuable to the user. The behavior includes the mass storage of digital artifacts and the retainment of unnecessary or irrelevant electronic data. The term is increasingly common in pop culture, used to describe the habitual characteristics of compulsive hoarding, but in cyberspace. As with physical space in which excess items are described as "clutter" or "junk," excess digital media is often referred to as "digital clutter."

Digital hoarding can lead to many problems:

- Digital clutter can make it more difficult to locate specific files among the extra irrelevant material.

- Excessive digital content takes up more hard drive space than it merits, and may even require the addition of extra digital storage to one’s computer or mobile phone.

- Server farms use more electricity as they need more disk drives. The extra load is especially notable in corporate domains. This adds to an individual’s or company’s electricity expenses and carbon footprint.

- Digital clutter can be mentally draining, requiring time and attention. For example, hoarded emails can make an inbox seem overwhelming. The user wastes time sifting through excess emails, which can result in lowered employee productivity.

- Digital hoarding can create an unhealthy attachment to digital content and foster a sort of “media addiction.” It is often good for one’s mental health to let go of useless clutter, and decluttering digital devices can help with decluttering the mind.

Compulsive decluttering is a pattern of behavior that is characterized by an excessive desire to discard objects in one's home and living areas. Other terms for such behavior includes obsessive compulsive spartanism. The homes of compulsive declutterers are often empty. It is the antonym of compulsive hoarding.

The most common methods for the treatment of specific phobias are systematic desensitization and in vivo or exposure therapy.

Treatment involves becoming conscious of the addiction through studying, therapy, group work, etc...

Research done by Michel Lejoyeux and Aviv Weinstein suggests that the best possible treatment for CB is through cognitive behavioral therapy. They suggest that a patient first be "evaluated for psychiatric comorbidity, especially with depression, so that appropriate pharmacological treatment can be instituted." Their research indicates that patients who received cognitive behavioral therapy over 10 weeks had reduced episodes of compulsive buying and spent less time shopping as opposed to patients who did not receive this treatment (251).

Lejoyeux and Weinstein also write about pharmacological treatment and studies that question the use of drugs on CB. They declare "Few controlled studies have assessed the effects of pharmacological treatment on compulsive buying, and none have shown any medication to be effective" (252). The most effective treatment is to attend therapy and group work in order to prevent continuation of this addiction.

Selective serotonin reuptake inhibitors such as fluvoxamine and citalopram may be useful in the treatment of CBD, although current evidence is mixed. Opioid antagonists such as naltrexone and nalmefene are promising potential treatments for CBD. A review concluded that evidence is limited and insufficient to support their use at present, however. Naltrexone and nalmefene have also shown effectiveness in the treatment of gambling addiction, an associated disorder.

Bibliomania is not to be confused with bibliophilia, which is the usual love of books and is not considered a clinical psychological disorder.

Other abnormal behaviours involving books include book-eating (bibliophagy), compulsive book-stealing (bibliokleptomania), and book-burying (bibliotaphy).

The consequences of oniomania, which may persist long after a spree, can be devastating, with marriages, long-term relationships, and jobs all feeling the strain. Further problems can include ruined credit history, theft or defalcation of money, defaulted loans, general financial trouble and in some cases bankruptcy or extreme debt, as well as anxiety and a sense of life spiraling out of control. The resulting stress can lead to physical health problems and ruined relationships, or even suicide.

Compulsive talking goes beyond the bounds of what is considered to be a socially acceptable amount of talking. The two main factors in determining if someone is a compulsive talker are talking in a continuous manner, only stopping when the other person starts talking, and others perceiving their talking as a problem. Personality traits that have been positively linked to this compulsion include assertiveness, willingness to communicate, self-perceived communication competence, and neuroticism. Studies have shown that most people who are talkaholics are aware of the amount of talking they do, are unable to stop, and do not see it as a problem.

Formal diagnosis may be performed by a psychologist, psychiatrist, clinical social worker, or other licensed mental health professional. To be diagnosed with OCD, a person must have obsessions, compulsions, or both, according to the Diagnostic and Statistical Manual of Mental Disorders (DSM). The Quick Reference to the 2000 edition of the DSM states that several features characterize clinically significant obsessions and compulsions. Such obsessions, the DSM says, are recurrent and persistent thoughts, impulses or images that are experienced as intrusive and that cause marked anxiety or distress. These thoughts, impulses or images are of a degree or type that lies outside the normal range of worries about conventional problems. A person may attempt to ignore or suppress such obsessions, or to neutralize them with some other thought or action, and will tend to recognize the obsessions as idiosyncratic or irrational.

Compulsions become clinically significant when a person feels driven to perform them in response to an obsession, or according to rules that must be applied rigidly, and when the person consequently feels or causes significant distress. Therefore, while many people who do not suffer from OCD may perform actions often associated with OCD (such as ordering items in a pantry by height), the distinction with clinically significant OCD lies in the fact that the person who suffers from OCD "must" perform these actions, otherwise they will experience significant psychological distress. These behaviors or mental acts are aimed at preventing or reducing distress or preventing some dreaded event or situation; however, these activities are not logically or practically connected to the issue, or they are excessive. In addition, at some point during the course of the disorder, the individual must realize that their obsessions or compulsions are unreasonable or excessive.

Moreover, the obsessions or compulsions must be time-consuming (taking up more than one hour per day) or cause impairment in social, occupational or scholastic functioning. It is helpful to quantify the severity of symptoms and impairment before and during treatment for OCD. In addition to the peron's estimate of the time spent each day harboring obsessive-compulsive thoughts or behaviors, concrete tools can be used to gauge the people’s condition. This may be done with rating scales, such as the Yale–Brown Obsessive Compulsive Scale (Y-BOCS). With measurements like these, psychiatric consultation can be more appropriately determined because it has been standardized.

OCD is sometimes placed in a group of disorders called the obsessive–compulsive spectrum.

Although most commonly done with the help of a therapist in a professional setting, exposure to dogs is also possible as a self-help treatment. First, the patient is advised to enlist the help of an assistant who can help set-up the exposure environment, assist in handling the dog during sessions, and demonstrate modeling behaviors. This should also be someone whom the patient trusts and who has no fear of dogs. Then, the patient compiles a hierarchy of fear provoking situations based on their rating of each situation. For example, on a scale from 0 to 100, a patient may feel that looking at photos of dogs may cause a fear response of only 50, however, petting a dog's head may cause of fear response of 100. This list of situations looking at dog photos) to most fearful (petting a dog's head) and the assistant helps the patient to identify common elements that contribute to the fear (i.e., size of the dog, color, how it moves, noise, whether or not it is restrained, etc.). Next, the assistant helps the patient recreate the least fearful situation in a safe, controlled environment, continuing until the patient has had an opportunity to allow the fear to subside thus reinforcing the realization that the fear is unfounded. Once a situation has been mastered, the next fearful situation is recreated and the process is repeated until all the situations in the hierarchy have been experienced.

Sample videos showing humans and dogs interacting without either exhibiting significant fear are available.

Theodore Millon identified five subtypes of the compulsive personality (2004). Any compulsive personality may exhibit one or more of the following:

Bibliomania can be a symptom of obsessive–compulsive disorder which involves the collecting or even hoarding of books to the point where social relations or health are damaged.

Zoophobia or animal phobia is a class of specific phobias to particular animals, or an irrational fear or even simply dislike of any non-human animals.

Examples of specific zoophobias would be entomophobias, such as that of bees (apiphobia). Fears of spiders (arachnophobia), birds (ornithophobia) and snakes (ophidiophobia) are also common. See the article at -phobia for the list of various phobias. Sigmund Freud mentioned that an animal phobia is one of the most frequent psychoneurotic diseases among children.

Zoophobia is not the sensible fear of dangerous or threatening animals, such as wild dogs (example: wolves, dingoes, and coyotes), big cats, bears or venomous snakes. It is a phobia of animals that causes distress or dysfunction in the individual's everyday life.

Compulsive behavior is defined as performing an act persistently and repetitively without it necessarily leading to an actual reward or pleasure. Compulsive behaviors could be an attempt to make obsessions go away. The act is usually a small, restricted and repetitive behavior, yet not disturbing in a pathological way. Compulsive behaviors are a need to reduce apprehension caused by internal feelings a person wants to abstain from or control. A major cause of the compulsive behaviors is said to be obsessive–compulsive disorder (OCD). "The main idea of compulsive behavior is that the likely excessive activity is not connected to the purpose to which it appears directed." Furthermore, there are many different types of compulsive behaviors including, shopping, hoarding, eating, gambling, trichotillomania and picking skin, checking, counting, washing, sex, and more. Also, there are cultural examples of compulsive behavior.

Impulse-control disorders have two treatment options: psychosocial and pharmacological. Treatment methodology is informed by the presence of comorbid conditions.

The fifth edition of the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-5), a widely used manual for diagnosing mental disorders, defines obsessive–compulsive personality disorder (in Axis II Cluster C) as an extensive pattern of preoccupation with perfectionism, orderliness, and interpersonal and mental control, at the cost of efficiency, flexibility and openness. Symptoms must appear by early adulthood and in multiple contexts. At least four of the following should be present:

1. Is preoccupied with details, rules, lists, order, organization, or schedules to the extent that the major point of the activity is lost.

2. Shows perfectionism that interferes with task completion (e.g., is unable to complete a project because his or her own overly strict standards are not met).

3. Is excessively devoted to work and productivity to the exclusion of leisure activities and friendships (not accounted for by obvious economic necessity).

4. Is overconscientious, scrupulous, and inflexible about matters of morality, ethics, or values (not accounted for by cultural or religious identification).

5. Is unable to discard worn-out or worthless objects even when they have no sentimental value.

6. Is reluctant to delegate tasks or to work with others unless they submit to exactly his or her way of doing things.

7. Adopts a miserly spending style toward both self and others; money is viewed as something to be hoarded for future catastrophes.

8. Shows rigidity and stubbornness.

Species dysphoria is the experience of dysphoria, sometimes including clinical lycanthropy (delusion or hallucination of one's self as an animal) and dysmorphia (excessive concern over one's body image), associated with the feeling that one's body is of the wrong species. Earls and Lalumière (2009) describe it as "the sense of being in the wrong (species) body... a desire to be an animal". Outside of psychological literature, the term is common within the otherkin and therian communities. The phenomenon is sometimes experienced in the context of sexual arousal to the image of one's self as an animal.

The naturally occurring sugar inositol has been suggested as a treatment for OCD.

Nutrition deficiencies may also contribute to OCD and other mental disorders. Vitamin and mineral supplements may aid in such disorders and provide nutrients necessary for proper mental functioning.

μ-Opioids, such as hydrocodone and tramadol, may improve OCD symptoms. Administration of opiate treatment may be contraindicated in individuals concurrently taking CYP2D6 inhibitors such as fluoxetine and paroxetine.

Much current research is devoted to the therapeutic potential of the agents that affect the release of the neurotransmitter glutamate or the binding to its receptors. These include riluzole, memantine, gabapentin, N-acetylcysteine, topiramate and lamotrigine.

Boanthropy is a psychological disorder in which a human believes himself or herself to be a bovine.

Lovesickness refers to an informal affliction that describes negative feelings associated with rejection, unrequited love or the absence of a loved one. It can manifest as physical as well as mental symptoms. It is not to be confused with the condition of being lovestruck, which refers to the physical and mental symptoms associated with falling in love. The term lovesickness is rarely used in medical or psychological fields.

Many people believe lovesickness was created as an explanation for longings, but it can be associated with depression and various mental health problems.

Kleptomania is characterized by an impulsive urge to steal purely for the sake of gratification.

In the U.S. the presence of kleptomania is unknown but has been estimated at 6 per 1000 individuals. Kleptomania is also thought to be the cause of 5% of annual shoplifting in the U.S. If true, 100,000 arrests are made in the U.S. annually due to kleptomaniac behavior.