Managing the comorbidity of schizophrenia and ADHD

Longitudinal study on all-cause and suicide mortality among individuals with attention deficit hyperactivity disorder

BACKGROUND

Previous research has linked attention deficit hyperactivity disorder (ADHD) with an increased risk of all-cause mortality, primarily owing to unnatural causes such as accidents and suicides. This increase may be attributable to the co-occurrence of major psychiatric disorders, including schizophrenia (SCZ), bipolar disorder (BD), major depressive disorder (MDD), autism spectrum disorder (ASD), anxiety disorders, substance use disorders (SUDs), and personality disorders (PDs). This study examined the all-cause and specific-cause mortality rates in individuals with ADHD and the influence of psychiatric comorbidities.

METHODS

Between 2003 and 2017, 1.17 million individuals were enrolled in the study, of which 233,886 received a diagnosis of ADHD from the Taiwan's National Health Insurance Research Database. A 1:4 sex- and birth year-matched control group without ADHD was also included. Hazard ratios (HRs) for mortality rates were estimated between groups after adjusting for demographic data.

RESULTS

During the follow-up period, 781 individuals with ADHD died. The HR for all-cause mortality was 1.45 (95% confidence interval [CI]: 1.30-1.61), largely owing to unnatural causes, particularly suicide. Suicide rates were particularly high in individuals with ADHD and psychiatric comorbidities: the HRs for suicide were 47.06 in ADHD with SUDs (95% CI: 6.12-361.99), 32.02 in ADHD with SCZ (7.99-128.29), 23.60 in ADHD with PDs (7.27-76.66), 10.11 in ADHD with anxiety disorders (5.74-17.82), 9.30 in ADHD with BD (4.48-19.33), 8.36 in ADHD with MDD (5.66-12.35), and 6.42 in ADHD with ASD (1.83-22.53) relative to ADHD only.

DISCUSSION

ADHD was associated with increased mortality rates, primarily owing to suicide. The presence of major psychiatric comorbidities was associated with a further increase in suicide mortality risk.

Associations between ADHD and risk of six psychiatric disorders: a Mendelian randomization study

BACKGROUND

Observational studies and diagnostic criteria have indicated that Attention Deficit Hyperactivity Disorder (ADHD) frequently comorbid with various psychiatric disorders. Therefore, we conducted a Mendelian randomization (MR) study to explore this potential genetic association between ADHD and six psychiatric disorders.

METHODS

Using a two-sample Mendelian randomization (MR) design, this study systematically screened genetic instrumental variables (IVs) based on the genome-wide association studies (GWAS) of ADHD and six psychiatric disorders, with the inverse variance weighted (IVW) method as the primary approach.

RESULTS

The study revealed a positive and causal association between ADHD and the risk of ASD, with an odds ratio (OR) of 2.328 (95%CI: 1.241-4.368) in the IVW MR analysis. Additionally, ADHD showed a positive causal effect on an increased risk of schizophrenia, with an OR of 1.867 (95%CI: 1.260-2.767) in the IVW MR analysis. However, no causal effect of Tic disorder, Mental retardation, Mood disorders and Anxiety disorder with ADHD was found in the analysis mentioned above.

CONCLUSION

Our MR analysis provides robust evidence of the causal role of ADHD in increasing the risk of ASD and schizophrenia. However, ADHD is not associated with the risk of Tic Disorder, Mental Retardation, Mood Disorders and Anxiety Disorder. This suggests the need for increased attention to the co-occurrence of ADHD-ASD or ADHD-schizophrenia and the implementation of timely intervention and treatment.

Psychosis Induced by Methylphenidate in Children and Young Patients With Attention-Deficit Hyperactivity Disorder

Attention-deficit hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders diagnosed in children of this era. ADHD in children and adults is challenging but highly manageable. Children with ADHD cannot focus, are hyperactive, and appear withdrawn. These symptoms make them endure difficulties in learning and create academic challenges. Methylphenidate (MPH) is one of the psychostimulants used as a first-line therapy for ADHD. In this literature review, we have gathered information that describes the evidence of psychotic symptoms in children and young patients with ADHD as a side effect of MPH. We used articles from the National Library of Medicine (PubMed) and Google Scholar to gather the relevant information. Our findings concluded that MPH can increase the risk of psychosis, particularly when taken in high doses. It is still unclear whether the psychotic range of symptoms occurred due to an increased dopamine (DA) level caused by MPH or as a predominant feature of ADHD or if there was another comorbid feature in the history of the patient that led to psychosis. However, a necessary step for every medical practitioner prescribing psychostimulants is that they enlighten the patient and caregiver that this rare but threatening side effect is a possibility.

Internalizing and externalizing comorbidity and symptom burden in a VA ADHD specialty evaluation clinic

The purpose of this study was to evaluate psychiatric diagnosis and symptom comorbidity in veterans diagnosed with attention-deficit/hyperactivity disorder (ADHD). Study design was retrospective chart review from an ADHD evaluation clinic at a Veterans Affairs hospital. Participants were 227 military veterans who completed a standardized ADHD assessment and produced valid Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) profiles. There were no differences in rates of internalizing or externalizing psychiatric conditions diagnosed in inattentive compared to combined ADHD presentations. However, compared to a subsample with no psychiatric diagnoses, individuals diagnosed with ADHD endorsed significantly more internalizing symptom burden, with combined ADHD veterans also endorsing significantly greater levels of negative emotions and neuroticism. Base rates of comorbid classes of psychiatric diagnoses were not increased in individuals with ADHD, though higher rates of trauma disorders were seen in the combined group compared to the inattentive group. Multivariate base rates of MMPI-2-RF Restructured Clinical scales across various subgroups are presented. There was evidence for differential phenotypes of psychiatric symptoms across ADHD presentations in clinically referred veterans, predominantly related to higher rates of internalizing symptoms.

Prolonged epigenomic and synaptic plasticity alterations following single exposure to a psychedelic in mice

Clinical evidence suggests that rapid and sustained antidepressant action can be attained with a single exposure to psychedelics. However, the biological substrates and key mediators of psychedelics' enduring action remain unknown. Here, we show that a single administration of the psychedelic DOI produces fast-acting effects on frontal cortex dendritic spine structure and acceleration of fear extinction via the 5-HT2A receptor. Additionally, a single dose of DOI leads to changes in chromatin organization, particularly at enhancer regions of genes involved in synaptic assembly that stretch for days after the psychedelic exposure. These DOI-induced alterations in the neuronal epigenome overlap with genetic loci associated with schizophrenia, depression, and attention deficit hyperactivity disorder. Together, these data support that epigenomic-driven changes in synaptic plasticity sustain psychedelics' long-lasting antidepressant action but also warn about potential substrate overlap with genetic risks for certain psychiatric conditions.

Functional MHCI deficiency induces ADHD-like symptoms with increased dopamine D1 receptor expression

Inappropriate synaptic development has been proposed as a potential mechanism of neurodevelopmental disorders, including attention-deficit hyperactivity disorder (ADHD). Major histocompatibility complex class I (MHCI), an immunity-associated molecule expressed by neurons in the brain, regulates synaptic development; however, the involvement of MHCI in these disorders remains elusive. We evaluated whether functional MHCI deficiency induced by β2m^-/-Tap1^-/- double-knockout in mice leads to abnormalities akin to those seen in neurodevelopmental disorders. We found that functional MHCI deficiency induced locomotor hyperactivity, motor impulsivity, and attention deficits, three major symptoms of ADHD. In contrast, these mice showed normal spatial learning, behavioral flexibility, social behavior, and sensorimotor integration. In the analysis of the dopamine system, upregulation of dopamine D1 receptor (D1R) expression in the nucleus accumbens and a greater locomotor response to D1R agonist SKF 81297 were found in the functional MHCI-deficient mice. Low-dose methylphenidate, used for the treatment of ADHD patients, alleviated the three behavioral symptoms and suppressed c-Fos expression in the D1R-expressing medium spiny neurons of the mice. These findings reveal an unexpected role of MHCI in three major symptoms of ADHD and may provide a novel landmark in the pathogenesis of ADHD.

Prodopaminergic Drugs for Treating the Negative Symptoms of Schizophrenia: Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND

The negative symptoms of schizophrenia pose a heavy burden on patients and relatives and represent an unmet therapeutic need. The observed association of negative symptoms with impaired reward system function has stimulated research on prodopaminergic agents as potential adjunctive treatments.

METHODS

We conducted a systematic review and meta-analysis of published randomized controlled trials of amphetamine, methylphenidate, modafinil, armodafinil, lisdexamphetamine, L-dopa, levodopa, bromocriptine, cabergoline, quinagolide, lisuride, pergolide, apomorphine, ropinirole, pramipexole, piribedil, and rotigotine augmentation in schizophrenia and schizoaffective disorder.Medline, EMBASE, and several other databases as well as trial registries were searched for placebo-controlled trials.

RESULTS

Ten randomized controlled trials were included in the meta-analysis, 6 trials on modafinil, 2 on armodafinil, 1 on L-dopa, and 1 on pramipexole. Overall, prodopaminergic agents did not significantly reduce negative symptoms. Restricting the analysis to studies requiring a minimum threshold for negative symptom severity, modafinil/armodafinil showed a significant but small effect on negative symptoms. A subset of studies allowed for calculating specific effects for the negative symptom dimensions diminished expression and amotivation, but no significant effect was found. Prodopaminergic agents did not increase positive symptom scores.

CONCLUSIONS

The currently available evidence does not allow for formulating recommendations for the use of prodopaminergic agents for the treatment of negative symptoms. Nevertheless, the observed improvement in studies defining a minimum threshold for negative symptom severity in the absence of an increase in positive symptoms clearly supports further research on these agents.