PSY 699 Assignment Analyze the Etiology of Psychopathlogy Disorders Through One Lens

PSY 699 Assignment Analyze the Etiology of Psychopathlogy Disorders Through One Lens

PSY 699 Assignment Analyze the Etiology of Psychopathlogy Disorders Through One Lens

Psychopathology is the scientific study of the abnormal mind. Genetics have been significantly attributed to the development of psychopathology disorders. The purpose of this paper is to describe the etiology and etiology of psychopathology disorders according to the perspective of genetics/neuroscience.



Twin Studies have explained the genetic etiology of schizophrenia by showing that the rate of schizophrenia among monozygotic twins is four-fold that of dizygotic twins and 50% times that of the general population. Identical twins reared apart have the same schizophrenia prevalence rate (Trifu et al., 2020). On the other hand, adoption studies show that children born to schizophrenic parents and brought up by non-schizophrenic parents have a similar rate to their controls (Trifu et al., 2020). However, children raised by schizophrenic patients but born of non-schizophrenic patients do not have high rates of developing schizophrenia.

Regarding neuroscience, the development of Schizophrenia is associated with abnormalities in the neurotransmitters norepinephrine, serotonin, acetylcholine, and GABA. Increased limbic dopamine activity is linked with positive psychotic symptoms, whereas decreased frontal dopamine activity is linked with negative symptoms (Kesby et al., 2018). Reduced GABA activity results in increased dopamine activity leading to psychotic symptoms. Besides, elevated norepinephrine levels in psychosis lead to increased sensitization to sensory input.


            Antipsychotic agents are used primarily in the treatment of schizophrenia. They are classified into two major classes: Typical and atypical antipsychotics. The antipsychotic effects of Typical antipsychotics owe their competitive blockage to dopamine receptors. They are effective in the treatment of positive symptoms of schizophrenia. Examples of Typical antipsychotics include chlorpromazine, thioridazine, fluphenazine, and haloperidol. Atypical antipsychotics have a broader spectrum of receptor activity, with effects on Serotonin, dopamine, and GABA (Kesby et al., 2018). They block both serotonin and dopamine and have fewer extrapyramidal adverse effects than the typical agents. Current antipsychotic therapy commonly employs the use of atypical agents to minimize the risk of debilitating movement disorders associated with the typical drugs that act primarily at the D2 dopamine receptor. However, it is important to note that the Atypical antipsychotics exhibit an efficacy that is equivalent to, or occasionally exceeds, that of the typical agents.

Personality Disorders


Twin and adoption studies have established that personality disorders are moderate to strongly heritable. The heritability of personality disorders is approximately 30%- 80% (Gescher et al., 2018). Besides, Paranoid and Schizotypal Personality disorders have been genetically linked with schizophrenia. The heritability of paranoid personality disorder (PPD) was approximated at 50% in a study of 122 twins 4–15 years and at 21% and 28% in others. In addition, family and twin studies have found evidence that Schizotypal personality disorder is heritable, and is influenced by familial-genetic and unique environmental factors.

Regarding Antisocial personality disorder, it is approximated that genetic factors account for about half of the variance in antisocial behavior. Twin and adoption studies on antisocial behavior found that 32% of the variance in antisocial behavior can be attributed to additive genetic factors. Furthermore, some genetic studies suggest a link between polymorphism of the serotonin transporter gene and the schizoid trait in persons with schizoid personality disorder (Gescher et al., 2018). Moreover, the heritability of Narcissistic personality disorder (NPD) is estimated at 77% and 24% in the general population, with no shared environmental influence or sex effect. Furthermore, the heritability estimate of Histrionic personality disorder is about 63% from a clinical sample and roughly 31% in the general population. The heritability of Avoidant personality disorder is approximated at 28% in a clinical sample and 35% in a community sample.

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Family and twin studies on Borderline Personality Disorder (BPD) reveal familial aggregation and genetic predisposition for BPD. Skoglund et al. (2021) conducted a study that found that relatives of persons with BPD had a higher risk of developing BPD than persons without familial vulnerability. For instance, the study found a 4.7 times increased risk for full siblings. In addition, the heritability of clinically diagnosed BPD was approximated at 46%, which shows the heritability of dimensional BPD traits in general population twin samples. Furthermore, biological factors, like abnormal monoaminergic functioning, especially in serotonergic function and prefrontal neuropsychological dysfunction, have been linked with BPD. Serotonin transporter (5-HTT) genes have been linked with borderline, anxious, depressive, and obsessive-compulsive features.


There are no approved pharmacological treatments for personality disorders. Treatment usually entails psychotherapy interventions. The commonly used psychotherapies in patients with personality disorders are Psychodynamic psychotherapy, cognitive behavioral therapy (CBT), and Interpersonal therapy (Setkowski et al., 2023). Medications are used to manage specific symptoms of personality disorders like anxiety and depression. Small doses of antidepressants, antipsychotics, and psychostimulants have been found effective in some patients. Benzodiazepines help to alleviate interpersonal anxiety.


The forms of dementia with a genetic etiology include Alzheimer’s disease (AD), Huntington’s disease, and some forms of Frontotemporal dementia (FTD).


Genetics plays a role in the development of Alzheimer’s dementia. Almost 40% of AD patients have a family history of Alzheimer’s disease. Besides, the concordance rate for monozygotic twins is 43%, while for dizygotic twins is 8%. Apolipoprotein E gene found in chromosome 19 is the most important gene associated with Dementia of the Alzheimer’s type. The gene occurs in three forms in humans: types 2, 3, and 4. Every individual carries two Apolipoprotein genes, which can be the same type or a mixture of two types (Jiao et al., 2021). Studies have found that persons with at least one type 4 and especially those with two, such as 4,4, are at a higher risk of developing Alzheimer’s disease earlier in life than persons with the other types of Apolipoprotein E. However, there exists a rare form of Alzheimer’s dementia, which is passed from generation to generation called Familial Alzheimer’s disease (FAD). If a parent has a mutated gene that causes FAD, each offspring has a 50% likelihood of inheriting it. The presence of the gene means that the individual will eventually develop Alzheimer’s disease, mostly in their 40s or 50s.

Huntington’s disease is a genetic autosomal dominant disorder with complete penetrance. It is characterized by choreoathetoid movement and dementia. The probability of the development of Huntington’s disease in a person with one parent with the disease is 50% (Jiao et al., 2021). Huntington’s disease develops following a mutation in the gene for a protein named huntingtin. The defect results in the building blocks of DNA called cytosine, adenine, and guanine (CAG) repeating multiple times than normal.

FTD is categorized into familial FTD and sporadic FTD. Familial FTD is described as when multiple individuals in a family across back-to-back generations have FTD or a related disorder. Some familial FTDs are caused by a single gene, which is called genetic FTD (Jiao et al., 2021). Approximately 10–20% of all FTD cases are regarded as genetic FTD. Genetic FTD is caused by a single gene variant, called an illness-causing gene mutation.


The treatment of Alzheimer’s dementia includes cholinesterase inhibitors like Donepezil, rivastigmine, and galatamine. Cholinesterase inhibitors improve cognition and slow cognitive decline in patients with mild to moderate Alzheimer’s dementia. The newest drug for AD dementia is mementine, which acts on glutamate receptors (Jiao et al., 2021). Treatment of Huntington’s disease includes benzodiazepines and antidepressants, which are used to treat symptoms of anxiety, insomnia, and depression. Psychotic symptoms are treated with antipsychotic medication, usually atypical antipsychotics. There are no current treatments available to cure FTD or slow its progression. However, antidepressants are often used to alleviate anxiety and control obsessive-compulsive behaviors. Antipsychotics are used to alleviate irrational and compulsive behaviors. 

Eating Disorders

The commonly diagnosed eating disorders are Anorexia nervosa and Bulimia nervosa.


Neuro-scientific and genetic factors have been implicated with Anorexia nervosa (AN). Starvation leads to many biochemical changes, some of which usually occur in depression, like hypercortisolemia and non-suppression by dexamethasone. Concerning genetics, AN has a strong genetic element and often has a familial presentation. Studies reveal a four-fold increase in the tendency to AN among family members (Paolacci et al., 2020). Besides, female relatives of patients diagnosed with AN have an 11 times greater risk of developing the condition compared to the general population. Evidence shows increased AN in sisters. Furthermore, studies have shown that genes contribute to a 50%- 74% risk of developing AN. Monozygotic twins have higher odds of developing AN than dizygotic twins.

Serotonin and norepinephrine have been associated with Bulimia nervosa. Plasma endorphin levels are usually elevated in some patients with bulimia nervosa who vomit. The feeling of well-being after inducing vomiting that some of patients experience is mediated by elevated endorphin levels. Regarding the genetic etiology, an increased frequency of bulimia nervosa has been found in first-degree relatives of persons with the condition. A study by Yao et al. (2021) found the heritability of clinically diagnosed AN and bulimia nervosa to be 43% and 41%, respectively. About 41% of the observed variation of bulimia nervosa was explained by genetic variance, while the remaining variance was linked to unique environmental variance.


Inpatient treatment programs are recommended for patients diagnosed with anorexia nervosa who are 20% below the expected weight for height. For patients who are 30% below their expected weight psychiatric hospitalization is recommended. Some studies support the use of cyproheptadine, which has antihistaminic and antiserotonergic properties, for patients with anorexia nervosa restricting type. Amitriptyline is also reported to have some benefits in anorexia nervosa (Yao et al., 2021). Treatment also entails psychotherapy interventions like Dynamic psychotherapy, Cognitive-behavioral therapy, and Family therapy.

Inpatient treatment is usually indicated in patients with Bulimia nervosa who have electrolyte and metabolic disturbances as a result of severe purging. Antidepressants have been found helpful in treating bulimia including SSRIs, Imipramine, desipramine, trazodone, and monoamine oxidase inhibitors (MAOIs). Psychotherapy interventions used in managing bulimia include Cognitive-behavioral therapy and dynamic psychotherapy.

Sleep Disorders

            Insomnia is the most common sleep disorder and its etiology has a genetic component. Sleep-wake traits, like sleep duration and timing, are heritable and regulated by multiple genes. Human studies have associated genetic mechanisms in the etiology of insomnia (Melhuish et al., 2021). The current evidence indicates marked heritability and multi-gene association in the pathophysiology of insomnia. Genes associated with brain functioning, regulation of arousal, and sleep-wake processes have consistently been found to be linked with insomnia. The complex interplay of these genes accounts for the heterogeneity identified in insomnia symptoms and implications. Large genome-wide association studies (GWAS) have identified 57 to 248 genetic associations with insomnia. These include genetic associations linked to sleep quality, duration, and timing. Various genes are associated with insomnia, including GABRB3, which is involved in the regulation of GABAergic inhibition (Melhuish et al., 2021). Another gene is 3111T/C Clock, which is involved in the timing of the circadian rhythm. In addition, 5HTTLPR regulates serotonin in the synapse.


Insomnia treatment comprises both pharmacological and non-pharmacological interventions.  Pharmacological therapies include Benzodiazepines like triazolam, temazepam, flurazepam, quazepam and estazolam. These benzodiazepines have demonstrated therapeutic benefits on sleep onset and maintenance (Krystal et al., 2019). Z drugs like zolpidem are used to treat sleep onset and maintenance problems in younger adults. Melatonin receptor agonists are also used, mainly melatonin and ramelteon. Antidepressants are also used to treat insomnia and the commonly used ones are trazodone, doxepin, mirtazapine, and Amitriptyline.

The most widely used non-pharmacological treatment is cognitive behavioral therapy for insomnia (CBT‐I). It comprises educational, cognitive, and behavioral components (Krystal et al., 2019). CBT‐I has been found effective in alleviating insomnia and improving sleep across a wide range of patient populations. Other non-pharmacological treatment interventions include transcendental meditation, deconditioning techniques, relaxation tapes, and sleep hygiene measures.

Substance Abuse

Substance use disorders (SUDs) are influenced by genetic factors. Twin and family studies reveal strong familial inheritance patterns for SUDs. According to Deak and Johnson (2021), heritability estimates across SUDs differ but generally indicate that genetic influences account for about 50% of the risk. Nicotine and opiates have been found to have the highest evidence of substance-specific genetic factors. The heritability estimates for alcohol use disorder (AUD) range from 0.50 to 0.64. Besides, heritable factors have been linked across the stages of cigarette smoking and nicotine use disorder, with a range of heritability approximated for nicotine dependence of 0.30 to 0.70.

Additionally, twin and family studies have identified shared genetic and environmental factors across the stages of cannabis use and abuse.  The heritability estimates from twin studies of cannabis use disorder range from 0.51 to 0.59, which is to some extent, higher than the estimates for cannabis use (Deak & Johnson, 2021). Twin and family studies estimated that approximately 50% of the risk of opioid dependence is a result of additive genetic factors. It is approximated that 38% of the variation in opioid addiction is because of genetic factors particular to opioids. Moreover, the heritability of cocaine-use disorder is estimated at 0.40 to 0.80. There is also evidence of a common genetic vulnerability of cocaine-use disorder with other SUDs, particularly cannabis, but minimal evidence of cocaine-specific genetic influence.


The treatment of SUDs includes a combination of pharmacological and non-pharmacological therapies. Alcohol, nicotine, and opioids are the only substances with FDA-approved pharmacological treatments. AUD is treated with Disulfiram, Naltrexone, and Acamprosate (Deak & Johnson, 2021). Treatment options for opioid use disorder include naltrexone, methadone, and buprenorphine, which are usually combined with naloxone to lower the risk of misuse. Nicotine use disorder is treated with varenicline, bupropion, and nicotine replacement therapy (NRT).

Anxiety Disorders

Anxiety disorders are associated with genetic factors. Penninx et al. (2021) explain that the heritability of anxiety disorders varies, but heritability estimates meet rates of approximately 35% for generalized anxiety disorder (GAD) and approximately 50% for social anxiety disorder, panic disorder, and agoraphobia. The mechanism of inheritance of anxiety disorders is complex, with numerous genetic variants of small effects interacting with, or adding to other risk factors. The genetic element of anxiety disorders overlaps within the various disorders and with the non-pathological anxiety dimension. Furthermore, fear disorders like agoraphobia and panic disorder share some genetic risk with distress disorders (Penninx et al., 2021). Genetic correlations further suggest that depression and GAD have significant genetic overlap and that they are genetically partly distinct from fear disorders.

Meier and Deckert (2019) explain that the risk in first-degree relatives of patients to develop an anxiety disorder is about four to six times higher compared with relatives of healthy subjects. Heritability estimates from twin studies ranged approximately 30–50%. Furthermore, family and twin studies suggest that genetic contributions cross the diagnostic boundaries of anxiety disorders and are common in normal and pathological anxiety. First-degree relatives of patients with one anxiety disorder also have a risk of developing a range of other anxiety disorders. Besides, twin studies have established a genetic overlap of almost all anxiety disorders.


Treatment for anxiety disorders includes both psychotherapy and pharmacotherapy. Cognitive behavioral therapy is the most widely used and effective psychotherapy intervention for anxiety disorders. It is the recommended first-line psychotherapy. The pharmacological agents with the highest level of supporting evidence in treating anxiety disorder are selective serotonin reuptake inhibitors (SSRI) and selective noradrenaline reuptake inhibitors (SNRI) Garakani et al., 2020). SSRIs and SNRIs are the first-line therapies for panic disorder, GAD, and social anxiety disorder. Other treatments include Benzodiazepines, tricyclic antidepressants (TCAs), Buspirone, trifluoperazine, and mixed antidepressants.

Mood Disorders

Depressive disorders are the most diagnosed mood disorders and have been attributed to genetic factors. Family and twin studies show the contribution of genetic factors to the risk of the onset of depressive disorders. According to Shadrina et al. (2018), family and twin studies provide strong evidence of the input of genetic factors to the risk of depression. For example, a twin research study shows depression to have a heritability rate of 37%. Besides, data from family studies reveal a 2-3 fold increase in the risk of developing depression in first-degree offspring of patients with depression. Furthermore, heritability has been found to contribute to the severe forms of depression.


The treatment of depressive disorders includes both pharmacological and psychotherapy interventions. Pharmacologic therapies include SSRIs, SNRIs, TCAs, Monoamine Oxidase Inhibitors, and Bupropion. SSRIs are the first-line therapy options for depressive disorders. Psychotherapy interventions include CBT, Interpersonal Psychotherapy, Mindfulness-based cognitive therapy (MBCT), and Family-focused treatment. Other therapies include Electroconvulsive therapy (ECT), Transcranial Magnetic stimulation, Light therapy, and Vagus nerve stimulation.


The above write-up has examined the etiological genetic/neuroscience perspective of various psychopathology disorders. Numerous studies have investigated the role genetics play in the development of psychopathology disorders. They have established that individuals with first-line relatives with psychopathology disorders have a higher risk of developing particular disorders compared to the general population.


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Gescher, D. M., Kahl, K. G., Hillemacher, T., Frieling, H., Kuhn, J., & Frodl, T. (2018). Epigenetics in personality disorders: today’s insights. Frontiers in psychiatry9, 579.

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Paolacci, S., Kiani, A. K., Manara, E., Beccari, T., Ceccarini, M. R., Stuppia, L., Chiurazzi, P., Dalla Ragione, L., & Bertelli, M. (2020). Genetic contributions to the etiology of anorexia nervosa: New perspectives in molecular diagnosis and treatment. Molecular genetics & genomic medicine8(7), e1244.

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Setkowski, K., Palantza, C., van Ballegooijen, W., Gilissen, R., Oud, M., Cristea, I. A., Noma, H., Furukawa, T. A., Arntz, A., van Balkom, A. J. L. M., & Cuijpers, P. (2023). Which psychotherapy is most effective and acceptable in the treatment of adults with a (sub)clinical borderline personality disorder? A systematic review and network meta-analysis. Psychological medicine, 53(8), 3261–3280.

Shadrina, M., Bondarenko, E. A., & Slominsky, P. A. (2018). Genetics Factors in Major Depression Disease. Frontiers in psychiatry9, 334.

Skoglund, C., Tiger, A., Rück, C., Petrovic, P., Asherson, P., Hellner, C., … & Kuja-Halkola, R. (2021). Familial risk and heritability of diagnosed borderline personality disorder: a register study of the Swedish population. Molecular psychiatry26(3), 999-1008.

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