Movement disorders should be a criterion for schizophrenia in DSM-V

Impaired motor development in children with familial high risk of schizophrenia or bipolar disorder and the association with psychotic experiences: a 4-year Danish observational follow-up study

BACKGROUND

Motor abnormalities have clinical relevance as a component of psychotic illness; they are not only a proxy of altered neurodevelopment, but also intimately related to psychotic risk. We aimed to assess motor development and its association with psychotic experiences in children with familial high risk (FHR) of schizophrenia or bipolar disorder compared with controls.

METHODS

The Danish High Risk and Resilience Study is a prospective longitudinal cohort study, for which participants were extracted from Danish registers. Children born in Denmark between Sept 1, 2004, and Aug 31, 2009, with no, one, or two parents born in Denmark with schizophrenia or bipolar disorder, could be included in the study. No ethnicity data were collected. Children with no biological parent diagnosed with schizophrenia spectrum disorder or bipolar disorder were matched to children with FHR of schizophrenia (one or two parents with schizophrenia spectrum disorder) on the basis of sex, age, and municipality. Children with FHR of bipolar disorder (one or two parents with bipolar disorder) were included as a non-matched group. We assessed motor function in children with FHR of schizophrenia, children with FHR of bipolar disorder, and children in the control group at approximately age 8 years (baseline; 2013-16) and age 12 years (follow-up; 2017-20) using the Movement Assessment Battery for Children-Second Edition (Movement ABC-2). Psychotic experiences were assessed using the psychosis section of the Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version. Raters were masked regarding familial risk status. Motor development from baseline to follow-up in the different groups was assessed using a linear mixed model. Logistic regression examined the relationship between definite motor problems (≤5th percentile on Movement ABC-2) and psychotic experiences.

FINDINGS

Between March 1, 2017, and June 30, 2020, we studied 437 children (234 [54%] boys, 203 [46%] girls; mean age 11·99 years [SD 0·26, range 11·08-12·86]). Children with FHR of schizophrenia showed stable motor developmental deficits in manual dexterity (difference in intercept -1·62 [95% CI -2·39 to -0·85], p<0·0001; difference in slope 0·17 [-0·48 to 0·81], p=0·61) and balance (difference in intercept -1·58 [-2·34 to -0·82], p<0·0001; difference in slope 0·32 [-0·34 to 0·99], p=0·34), and a developmental lag in aiming and catching (difference in slope -1·07 [-1·72 to -0·41], p=0·0015; difference in intercept -0·59 [-1·35 to 0·17], p=0·13) compared with controls. Children with FHR of bipolar disorder showed no motor developmental differences on a group basis. Compared with controls, children with FHR of schizophrenia were more likely to have definite motor problems (odds ratio [OR] 2·86 [95% CI 1·60 to 5·11], p=0·0004), as were children with FHR of bipolar disorder (OR 2·45 [1·28 to 4·70], p=0·0068). Children with definite motor problems across all groups were more likely (OR 1·90 [1·12 to 3·21, p=0·017] to have had psychotic experiences than children with no definite motor problems.

INTERPRETATION

Clinicians should be aware that motor impairment in childhood can reflect neurodevelopmental vulnerability to psychosis. Our findings contribute to the identification of early risk markers for severe mental illness, both for use by clinicians and for establishing a basis for future primary preventive intervention studies in the premorbid phase.

FUNDING

The Independent Research Fund Denmark, the Mental Health Services of the Capital Region of Denmark, the Lundbeck Foundation Initiative for Integrative Psychiatric Research (iPSYCH), Aarhus University, the Beatrice Surovell Haskell Fund, the Tryg Foundation, and the Innovation Fund Denmark.

TRANSLATION

For the Danish translation of the abstract see Supplementary Materials section.

A systematic review of the prognostic value of motor abnormalities on clinical outcome in psychosis

Schizophrenia spectrum disorders have heterogeneous outcomes and currently no marker predicts the course of illness. Motor abnormalities (MAs) are inherent to psychosis, the risk of psychosis, symptom severity, and brain alterations. However, the prognostic value of MAs is still unresolved. Here, we provide a systematic review of longitudinal studies on the prognostic role of MAs spanning individuals at clinical high risk for psychosis (CHR), patients with first-episode psychosis (FEP), and chronic schizophrenia. We included 68 studies for a total of 23,630 subjects that assessed neurological soft signs (NSS), hypo- or hyperkinetic movement disorders and/or catatonia as a prognostic factor on clinical and functional outcomes. We found increased levels of MAs, in particular NSS, parkinsonism, and dyskinesia, were related to deteriorating symptomatic and poor functional outcome over time. Collectively, the findings emphasize the clinical, prognostic and scientific relevance of MA assessment and detection in individuals with or at risk of psychosis. In the future, instrumental measures of MA are expected to further augment detection, early intervention and treatment strategies in psychosis.

Instrumental measurements of spontaneous dyskinesia and schizotypy in subjects with auditory verbal hallucinations and healthy controls

Spontaneous dyskinesia is associated with non-affective psychosis. Few studies investigated dyskinesia in individuals with subclinical psychotic experiences. We examined dyskinesia using instrumental measurements of force variability in 34 individuals with frequent auditory verbal hallucinations but without a clinical psychotic disorder and 31 matched healthy controls. Schizotypy was assessed using the Schizotypal Personality Questionnaire. We found a positive correlation between dyskinesia and schizotypy in the total group. In addition, when using a cut-off point based on the 95th percentile of force variability in the control group, we found a greater proportion of subjects with dyskinesia in the group with auditory verbal hallucinations than in the control subjects. Current findings are in agreement with the concept of psychosis as a continuous phenomenon and with movement disorders being an integral part of psychosis.

Long-stay psychiatric patients: a prospective study revealing persistent antipsychotic-induced movement disorder

OBJECTIVE

The purpose of this study was to assess the frequency of persistent drug-induced movement disorders namely, tardive dyskinesia (TD), parkinsonism, akathisia and tardive dystonia in a representative sample of long-stay patients with chronic severe mental illness.

METHOD

Naturalistic study of 209, mainly white, antipsychotic-treated patients, mostly diagnosed with psychotic disorder. Of this group, the same rater examined 194 patients at least two times over a 4-year period, with a mean follow-up time of 1.1 years, with validated scales for TD, parkinsonism, akathisia, and tardive dystonia.

RESULTS

The frequencies of persistent movement disorders in the sample were 28.4% for TD, 56.2% for parkinsonism, 4.6% for akathisia and 5.7% for tardive dystonia. Two-thirds of the participants displayed at least one type of persistent movement disorder.

CONCLUSIONS

Persistent movement disorder continues to be the norm for long-stay patients with chronic mental illness and long-term antipsychotic treatment. Measures are required to remedy this situation.

Movement disorders are associated with schizotypy in unaffected siblings of patients with non-affective psychosis

BACKGROUND

Movement disorders and schizotypy are both prevalent in unaffected siblings of patients with schizophrenia and both are associated with the risk of developing psychosis or schizophrenia. However, to date there has been no research into the association between these two vulnerability factors in persons with an increased genetic risk profile. We hypothesized that unaffected siblings of patients with non-affective psychosis have more movement disorders and schizotypy than healthy controls and that these co-occur.

METHOD

In a cross-sectional design we assessed the prevalence and inter-relationship of movement disorders and schizotypy in 115 unaffected siblings (mean age 27 years, 44% males) and 100 healthy controls (mean age 26 years, 51% males). Movement disorders were measured with the Abnormal Involuntary Movement Scale (AIMS), the Unified Parkinson Disease Rating Scale (UPDRS), the Barnes Akathisia Rating Scale (BARS), and one separate item for dystonia. Schizotypy was assessed with the Structured Interview for Schizotypy--Revised (SIS-R).

RESULTS

There were significant differences in the prevalence of movement disorders in unaffected siblings versus healthy controls (10% v. 1%, p<0.01) but not in the prevalence of schizotypy. Unaffected siblings with a movement disorder displayed significantly more positive and total schizotypy (p=0.02 and 0.03 respectively) than those without. In addition, dyskinesia correlated with positive schizotypy (r=0.51, p=0.02).

CONCLUSIONS

The association between movement disorders (dyskinesia in particular) with positive and total schizotypy in unaffected siblings suggests that certain vulnerability factors for psychosis or schizophrenia cluster in a subgroup of subjects with an increased genetic risk of developing the disease.