Antidepressants or antipsychotic medications may be used for more severe cases if intrusive thoughts do not respond to cognitive behavioral or exposure therapy alone. Whether the cause of intrusive thoughts is OCD, depression, or post-traumatic stress disorder, the selective serotonin reuptake inhibitor (SSRI) drugs (a class of antidepressants) are the most commonly prescribed. Intrusive thoughts may occur in persons with Tourette syndrome (TS) who also have OCD; the obsessions in TS-related OCD are thought to respond to SSRI drugs as well.

Antidepressants which have been shown to be effective in treating OCD include fluvoxamine (trade name Luvox), fluoxetine (Prozac), sertraline (Zoloft), paroxetine (Paxil), citalopram (Celexa), and clomipramine (Anafranil). Although SSRIs are known to be effective for OCD in general, there have been fewer studies on their effectiveness for intrusive thoughts. A retrospective chart review of patients with sexual symptoms treated with SSRIs showed the greatest improvement was in those with intrusive sexual obsessions typical of OCD. A study of ten patients with religious or blasphemous obsessions found that most patients responded to treatment with fluoxetine or clomipramine. Women with postpartum depression often have anxiety as well, and may need lower starting doses of SSRIs; they may not respond fully to the medication, and may benefit from adding cognitive behavioral or response prevention therapy.

Patients with intense intrusive thoughts that do not respond to SSRIs or other antidepressants may be prescribed typical and atypical neuroleptics including risperidone (trade name Risperdal), ziprasidone (Geodon), haloperidol (Haldol), and pimozide (Orap).

Studies suggest that therapeutic doses of inositol may be useful in the treatment of obsessive thoughts.

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.

Cognitive behavioral therapy (CBT) is a newer therapy than exposure therapy, available for those unable or unwilling to undergo exposure therapy. Cognitive therapy has been shown to be useful in reducing intrusive thoughts, but developing a conceptualization of the obsessions and compulsions with the patient is important.

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.

Cognitive-behavioral therapy (CBT) is a commonly implemented therapeutic intervention for compulsive hoarding. As part of cognitive behavior therapy, the therapist may help the patient to:

- Discover why he or she is compelled to hoard.

- Learn to organize possessions in order to decide what to discard.

- Develop decision-making skills.

- Declutter the home during in-home visits by a therapist or professional organizer.

- Gain and perform relaxation skills.

- Attend family and/or group therapy.

- Be open to trying psychiatric hospitalization if the hoarding is serious.

- Have periodic visits and consultations to keep a healthy lifestyle.

This modality of treatment usually involves exposure and response prevention to situations that cause anxiety and cognitive restructuring of beliefs related to hoarding. Furthermore, research has also shown that certain CBT protocols have been more effective in treatment than others. CBT programs that specifically address the motivation of the sufferer, organization, acquiring new clutter, and removing current clutter from the home have shown promising results. This type of treatment typically involves in-home work with a therapist combined with between-session homework, the completion of which is associated with better treatment outcomes. Research on Internet-based CBT treatments for the disorder (where participants have access to educational resources, cognitive strategies, and chat groups) has also shown promising results both in terms of short- and long-term recovery.

Other therapeutic approaches that have been found to be helpful are:

1. Motivational interviewing: originated in addiction therapy. This method is significantly helpful when used in hoarding cases in which insight is poor and ambivalence around change is marked.

2. Harm reduction rather than symptom reduction: also borrowed from addiction therapy. The goal is to decrease the harmful implications of the behavior, rather than the hoarding behaviors.

3. Group therapy: reduces social isolation and social anxiety and is cost-effective compared to one-on-one intervention.

4. Eye movement desensitization and reprocessing (EMDR) has been employed, although there is insufficient evidence for EMDR to be considered effective for treating compulsive hoarding (as for treating obsessive-compulsive disorders in general).

Individuals with hoarding behaviors are often described as having low motivation and poor compliance levels, and as being indecisive and procrastinators, which may frequently lead to premature termination (i.e., dropout) or low response to treatment. Therefore, it was suggested that future treatment approaches, and pharmacotherapy in particular, be directed to address the underlying mechanisms of cognitive impairments demonstrated by individuals with hoarding symptoms.

Mental health professionals frequently express frustration regarding hoarding cases, mostly due to premature termination and poor response to treatment. Patients are frequently described as indecisive, procrastinators, recalcitrant, and as having low or no motivation, which can explain why many interventions fail to accomplish significant results. To overcome this obstacle, some clinicians recommend accompanying individual therapy with home visits to help the clinician:

Likewise, certain cases are assisted by professional organizers as well.

Many people with sexual obsessions are alarmed that they seem to lose their sex drive. People with OCD may see this as evidence that they no longer have normal sexual attractions and are in fact deviant in some way. Some may wonder if medication is the answer to the problem. Medication is a double-edged sword. Drugs specifically for erectile dysfunction (i.e. Viagra, Cialis) are not the answer for people with untreated OCD. The sexual organs are working properly, but it is the anxiety disorder that interferes with normal libido.

Medications specifically for OCD (typically SSRI medications) will help alleviate the anxiety but will also cause some sexual dysfunction in about a third of patients. For many the relief from the anxiety is enough to overcome the sexual problems caused by the medication. For others, the medication itself makes sex truly impossible. This may be a temporary problem, but if it persists a competent psychiatrist can often adjust the medications to overcome this side-effect.

Treatment for OCPD includes psychotherapy, cognitive behavioral therapy, behavior therapy or self-help. Medication may be prescribed. In behavior therapy, a person with OCPD discusses with a psychotherapist ways of changing compulsions into healthier, productive behaviors. Cognitive analytic therapy is an effective form of behavior therapy.

Treatment is complicated if the person does not accept that they have OCPD, or believes that their thoughts or behaviors are in some sense correct and therefore should not be changed. Medication alone is generally not indicated for this personality disorder. Selective serotonin reuptake inhibitors (SSRIs) may be useful in addition to psychotherapy by helping the person with OCPD be less bogged down by minor details, and to lessen how rigid they are.

People with OCPD are three times more likely to receive individual psychotherapy than people with major depressive disorder. There are higher rates of primary care utilization. There are no known properly controlled studies of treatment options for OCPD. More research is needed to explore better treatment options.

The medications most frequently used are the selective serotonin reuptake inhibitors (SSRIs). Clomipramine, a medication belonging to the class of tricyclic antidepressants, appears to work as well as SSRIs but has a higher rate of side effects.

SSRIs are a second line treatment of adult obsessive compulsive disorder (OCD) with mild functional impairment and as first line treatment for those with moderate or severe impairment. In children, SSRIs can be considered as a second line therapy in those with moderate-to-severe impairment, with close monitoring for psychiatric adverse effects. SSRIs are efficacious in the treatment of OCD; people treated with SSRIs are about twice as likely to respond to treatment as those treated with placebo. Efficacy has been demonstrated both in short-term (6–24 weeks) treatment trials and in discontinuation trials with durations of 28–52 weeks.

In 2006, the National Institute of Clinical and Health Excellence (NICE) guidelines recommended antipsychotics for OCD that does not improve with SSRI treatment. For OCD the evidence for the atypical antipsychotic drugs risperidone and quetiapine is tentative with insufficient evidence for olanzapine. A 2014 review article found two studies that indicated that aripiprazole was "effective in the short-term" and found that "[t]here was a small effect-size for risperidone or anti-psychotics in general in the short-term"; however, the study authors found "no evidence for the effectiveness of quetiapine or olanzapine in comparison to placebo." While quetiapine may be useful when used in addition to an SSRI in treatment-resistant OCD, these drugs are often poorly tolerated, and have metabolic side effects that limit their use. None of the atypical antipsychotics appear to be useful when used alone. Another review reported that no evidence supports the use of first generation antipsychotics in OCD.

A guideline by the APA suggested that dextroamphetamine may be considered by itself after more well supported treatments have been tried.

People with sexual obsessions can devote an excessive amount of time and energy attempting to understand the obsessions. They usually decide they are having these problems because they are defective in some way, and they are often too ashamed to seek help. Because sexual obsessions are not as well-described in the research literature, many therapists may fail to properly diagnose OCD in a client with primary sexual obsessions. Mental health professionals unfamiliar with OCD may even attribute the symptoms to an unconscious wish (typically in the case of psychoanalysts or psychodynamic therapists), sexual identity crisis, or hidden paraphilia. Such a misdiagnosis only panics an already distressed individual. Fortunately, sexual obsessions respond to the same type of effective treatments available for other forms of OCD: cognitive-behavioral therapy and serotonergic antidepressant medications (SSRIs). People with sexual obsessions may, however, need a longer and more aggressive course of treatment.

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

In the case of pathological gambling, along with fluvoxamine, clomipramine has been shown effective in the treatment, with reducing the problems of pathological gambling in a subject by up to 90%. Whereas in trichotillomania, the use of clomipramine has again been found to be effective, fluoxetine has not produced consistent positive results. Fluoxetine, however, has produced positive results in the treatment of pathological skin picking disorder, although more research is needed to conclude this information. Fluoxetine has also been evaluated in treating IED and demonstrated significant improvement in reducing frequency and severity of impulsive aggression and irritability in a sample of 100 subjects who were randomized into a 14-week, double-blind study. Despite a large decrease in impulsive aggression behavior from baseline, only 44% of fluoxetine responders and 29% of all fluoxetine subjects were considered to be in full remission at the end of the study. Paroxetine has shown to be somewhat effective although the results are inconsistent. Another medication, escitalopram, has shown to improve the condition of the subjects of pathological gambling with anxiety symptoms. The results suggest that although SSRIs have shown positive results in the treatment of pathological gambling, inconsistent results with the use of SSRIs have been obtained which might suggest a neurological heterogeneity in the impulse-control disorder spectrum.

Research on treating BDD is limited. Yet anti-depressant medication, such as selective serotonin reuptake inhibitors (SSRIs), and cognitive-behavioral therapy (CBT) are considered effective. SSRIs can help relieve obsessive-compulsive and delusional traits, while cognitive-behavioral therapy can help patients recognize faulty thought patterns. Before treatment, it can help to provide psychoeducation, as with self-help books and support websites.

The inclusion of this problem in the obsessive-compulsive disorders and its relation with depression has led to some use of antidepressants as a treatment. Within antidepressant drugs, special attention has been paid to those related to serotonin, a brain neurotransmitter. This substance is supposed to be related to deficiencies in stimulus control, so that medicines like fluoxetine and fluvoxamine, which raise the level of serotonin in the brain, would be a pharmacological alternative to treat shopping addiction. Even though results are not conclusive, in the nineties some research was carried out which supported the effectiveness of tese treatments, at least in certain cases.

Treatment is similar to that for other forms of obsessive–compulsive disorder. Exposure and response prevention (ERP), a form of behavior therapy, is widely used for OCD in general and may be promising for scrupulosity in particular. ERP is based on the idea that deliberate repeated exposure to obsessional stimuli lessens anxiety, and that avoiding rituals lowers the urge to behave compulsively. For example, with ERP a person obsessed by blasphemous thoughts while reading the Bible would practice reading the Bible. However, ERP is considerably harder to implement than with other disorders, because scrupulosity often involves spiritual issues that are not specific situations and objects. For example, ERP is not appropriate for a man obsessed by feelings that God has rejected and is punishing him. Cognitive therapy may be appropriate when ERP is not feasible. Other therapy strategies include noting contradictions between the compulsive behaviors and moral or religious teachings, and informing individuals that for centuries religious figures have suggested strategies similar to ERP. Religious counseling may be an additional way to readjust beliefs associated with the disorder, though it may also stimulate greater anxiety.

Little evidence is available on the use of medications to treat scrupulosity. Although serotonergic medications are often used to treat OCD, studies of pharmacologic treatment of scrupulosity in particular have produced so few results that even tentative recommendations cannot be made.

Treatment of scrupulosity in children has not been investigated to the extent it has been studied in adults, and one of the factors that makes the treatment difficult is the fine line the therapist must walk between engaging and offending the client.

The treatment of shopping addiction – in contrast to other addictions as the gambling, alcohol or smoking - cannot seek to permanently remove the addicts from the behaviour. After therapy, they must be able to face consumer stimuli which surround them and maintain self-control. Because of this, the most usual therapies are behavioural ones., especially stimuli control and exposure and response prevention.

In psychology, relationship obsessive–compulsive disorder (ROCD) is a form of obsessive-compulsive disorder focusing on intimate relationships (whether romantic or non-romantic). Such obsessions can become extremely distressing and debilitating, having negative impacts on relationships functioning.

The phenomenological similarity and the suggested common basic biological dynamics of kleptomania and OCD, pathological gambling and trichotillomania gave rise to the theory that the similar groups of medications could be used in all these conditions. Consequently, the primary use of selective serotonin reuptake inhibitor (SSRI) group, which is a form of antidepressant, has been used in kleptomania and other impulse control disorders such as binge eating and OCD. Electroconvulsive therapy (ECT), lithium and valproic acid (sodium valproate) have been used as well.

The SSRI's usage is due to the assumption that the biological dynamics of these conditions derives from low levels of serotonin in brain synapses, and that the efficacy of this type of therapy will be relevant to kleptomania and to other comorbid conditions.

Opioid receptor antagonists are regarded as practical in lessening urge-related symptoms, which is a central part of impulse control disorders; for this reason, they are used in treatment of substance abuse. This quality makes them helpful in treating kleptomania and impulse control disorders in general. The most frequently used drug is naltrexone, a long-acting competitive antagonist. Naltrexone acts mainly at μ-receptors, but also antagonises κ- and λ-receptors.

There have been no controlled studies of the psycho-pharmacological treatment of kleptomania. This could be as a consequence of kleptomania being a rare phenomenon and the difficulty in achieving a large enough sample. Facts about this issue come largely from case reports or from bits and pieces gathered from a comparatively small number of cases enclosed in a group series.

The cause of OCPD is unknown. However, it is believed to involve a combination of genetic and environmental factors. Under the genetic theory, people with a form of the DRD3 gene will probably develop OCPD and depression, particularly if they are male. But genetic concomitants may lie dormant until triggered by events in the lives of those who are predisposed to OCPD. These events could include trauma faced during childhood, such as physical, emotional, or sexual abuse, or other psychological trauma. Under the environmental theory, OCPD is a learned behavior.

Those suffering from primarily obsessional OCD might appear normal and high-functioning, yet spend a great deal of time ruminating, trying to solve or answer any of the questions that cause them distress. Very often, Pure O sufferers are dealing with considerable guilt and anxiety. Ruminations may include trying to think about something 'in the right way' in an attempt to relieve this distress.

For example, an intrusive thought "I could just kill Bill with this steak knife" is followed by a catastrophic misinterpretation of the thought, i.e. "How could I have such a thought? Deep down, I must be a psychopath." This might lead a person to continually surf the Internet, reading numerous articles on defining psychopathy. This reassurance-seeking ritual will, ironically, provide no further clarification and could exacerbate the intensity of the search for the answer. There are numerous corresponding cognitive biases present, including thought-action fusion, over-importance of thoughts, and need for control over thoughts.

Despite how real and imposing the intrusive thoughts may be to an individual, the sufferer will probably never carry out actions related to these thoughts, even if one believes themselves capable of doing so. One of the reasons for this is because the person in question will go to extreme lengths to avoid circumstances which could trigger their intrusive thoughts.

The disorder is particularly easy to miss by many well-trained clinicians, as it closely resembles markers of generalized anxiety disorder and does not include observable, compulsive behaviors. Clinical "success" is reached when the sufferer becomes indifferent to the need to answer the question. While many clinicians will mistakenly offer reassurance and try to help their patient achieve a definitive answer (an unfortunate consequence of therapists treating primarily obsessional OCD as generalized anxiety disorder), this method only contributes to the intensity or length of the patient's rumination, as the neuropathways of the OCD brain will predictably come up with creative ways to "trick" the person out of reassurance, negating any temporary relief and perpetuating the cycle of obsessing.

The most effective treatment for primarily obsessional OCD appears to be cognitive-behavioral therapy. (more specifically exposure and response prevention (ERP)) as well as cognitive therapy (CT) which may or may not be combined with the use of medication, such as SSRIs. People suffering from OCD without overt compulsions are considered by some researchers more refractory towards ERP compared to other OCD sufferers and therefore ERP can prove less successful than CT.

ERP of Pure-O is theoretically based on the principles of classical conditioning and extinction. The spike often presents itself as a paramount question or disastrous scenario. A response that answers the spike in a way that leaves ambiguity is sometimes warranted. "If I don't remember what I had for breakfast yesterday my mother will die of cancer!" Using the antidote procedure, a cognitive response would be one in which the subject accepts this possibility and is willing to take the risk of his mother dying of cancer or the question recurring for eternity. No effort is expended in directly answering the question in an effort to find resolution. In another example, the spike would be, "Maybe I said something offensive to my boss yesterday." A recommended response would be, "Maybe I did. I'll live with the possibility and take the risk he'll fire me tomorrow." Using this procedure, it is imperative that the distinction be made between the therapeutic response and rumination. The therapeutic response does not seek to answer the question but to accept the uncertainty of the unsolved dilemma.

Acceptance and commitment therapy (ACT) is a newer approach that also is used to treat purely obsessional OCD, as well as other mental disorders such as anxiety and clinical depression. Mindfulness-based stress reduction (MBSR) may also be helpful for breaking out of the ruminative thinking process.

Treatment for perfectionism can be approached from many therapeutic directions. Some examples of psychotherapy include: cognitive-behavioral therapy (the challenging of irrational thoughts and formation of alternative ways of coping and thinking), psychoanalytic therapy (an analysis of underlying motives and issues), group therapy (where two or more clients work with one or more therapists about a specific issue, this is beneficial for those who feel as if they are the only one experiencing a certain problem), humanistic therapy (person-centered therapy where the positive aspects are highlighted), and self-therapy (personal time for the person where journaling, self-discipline, self-monitoring, and honesty with self are essential). Cognitive-behavioral therapy has been shown to successfully help perfectionists in reducing social anxiety, public self-consciousness, and perfectionism. By using this approach, a person can begin to recognize his or her irrational thinking and find an alternative way to approach situations. Cognitive-behavioral therapy is intended to help the person understand that it is okay to make mistakes sometimes and that those mistakes can become lessons learned.

Most treatment for problem gambling involves counseling, step-based programs, self-help, peer-support, medication, or a combination of these. However, no one treatment is considered to be most efficacious and no medications have been approved for the treatment of pathological gambling by the U.S. Food and Drug Administration (FDA). Only one treatment facility has been given a license to officially treat gambling as an addiction, and that was by the State of Virginia.

Gamblers Anonymous (GA) is a commonly used treatment for gambling problems. Modeled after Alcoholics Anonymous, GA uses a 12-step model that emphasizes a mutual-support approach. There are three in-patient treatment centers in North America. One form of counseling, cognitive behavioral therapy (CBT) has been shown to reduce symptoms and gambling-related urges. This type of therapy focuses on the identification of gambling-related thought processes, mood and cognitive distortions that increase one's vulnerability to out-of-control gambling. Additionally, CBT approaches frequently utilize skill-building techniques geared toward relapse prevention, assertiveness and gambling refusal, problem solving and reinforcement of gambling-inconsistent activities and interests.

As to behavioral treatment, some recent research supports the use of both activity scheduling and desensitization in the treatment of gambling problems. In general, behavior analytic research in this area is growing There is evidence that the SSRI paroxetine is efficacious in the treatment of pathological gambling. Additionally, for patients suffering from both pathological gambling and a comorbid bipolar spectrum condition, sustained release lithium has shown efficacy in a preliminary trial. The opioid antagonist drug nalmefene has also been trialled quite successfully for the treatment of compulsive gambling.

Cognitive-behavioural therapy (CBT) has primarily substituted the psychoanalytic and dynamic approach in the treatment of kleptomania. Numerous behavioural approaches have been recommended as helpful according to several cases stated in the literature. They include: hidden sensitisation by unpleasant images of nausea and vomiting, aversion therapy (for example, aversive holding of breath to achieve a slightly painful feeling every time a desire to steal or the act is imagined), and systematic desensitisation. In certain instances, the use of combining several methods such as hidden sensitisation along with exposure and response prevention were applied. Even though the approaches used in CBT need more research and investigation in kleptomania, success in combining these methods with medication was illustrated over the use of drug treatment as the single method of treatment.

Primarily cognitive obsessive-compulsive disorder (also commonly called "primarily obsessional OCD", purely obsessional OCD, Pure-O, OCD without overt compulsions or with covert compulsions) is a lesser-known form or manifestation of OCD. For people with primarily obsessional OCD, there are fewer observable compulsions, compared to those commonly seen with the typical form of OCD (checking, counting, hand-washing, etc.). While ritualizing and neutralizing behaviors do take place, they are mostly cognitive in nature, involving mental avoidance and excessiverumination. Primarily obsessional OCD often takes the form of intrusive thoughts of a distressing or violent nature.

Other step-based programs are specific to gambling and generic to healing addiction, creating financial health, and improving mental wellness. Commercial alternatives that are designed for clinical intervention, using the best of health science and applied education practices, have been used as patient-centered tools for intervention since 2007. They include measured efficacy and resulting recovery metrics.

Some treatments for internalizing disorders include antidepressants, electroconvulsive therapy, and psychotherapy.