Treatment with psychostimulants and atomoxetine in people with psychotic disorders: reassessing the risk of clinical deterioration in a real-world setting

BACKGROUND

Although attention-deficit hyperactivity disorder (ADHD) is often comorbid with schizophrenia spectrum and other psychotic disorders (SZSPD), concerns about an increased risk of psychotic events have limited its treatment with either psychostimulants or atomoxetine.

AIMS

To examine whether the risk of hospital admission for psychosis in people with SZSPD was increased during the year following the introduction of such medications compared with the year before.

METHOD

This was a retrospective cohort study using Quebec (Canada) administrative health registries, including all Quebec residents with a public prescription drug insurance plan and a diagnosis of psychotic disorder, defined by relevant ICD-9 or ICD-10 codes, who initiated either methylphenidate, amphetamines or atomoxetine, between January 2010 and December 2016, in combination with antipsychotic medication. The primary outcome was time to hospital admission for psychosis within 1 year of initiation. State sequence analysis was also used to visualise admission trajectories for psychosis in the year following initiation of these medications, compared with the previous year.

RESULTS

Out of 2219 individuals, 1589 (71.6%) initiated methylphenidate, 339 (15.3%) amphetamines and 291 (13.1%) atomoxetine during the study period. After adjustment, the risk of hospital admission for psychosis was decreased during the 12 months following the introduction of these medications when used in combination with antipsychotics (adjusted HR = 0.36, 95% CI 0.24-0.54; P < 0.0001).

CONCLUSIONS

These findings suggest that, in a real-world setting, when used concurrently with antipsychotic medication, methylphenidate, amphetamines and atomoxetine may be safer than generally believed in individuals with psychotic disorders.

Clozapine and Sweet's syndrome: case report

A patient developed fever, raised inflammatory markers and a maculopapular rash following commencement of clozapine for treatment of his schizoaffective disorder. Skin biopsy confirmed Sweet's syndrome. Identification of the cause was challenging, with a number of possible considerations including infection, malignancy and various potential drug triggers.This case highlights the difficulties in the diagnosis of Sweet's syndrome, as well as in identifying the original trigger, which can have significant consequences for management. Withdrawal of potentially causative drugs must be balanced with their benefits, and decisions must be made in the best interests of the patient. Following two courses of prednisolone and withdrawal of clozapine, the patient's rash and systemic symptoms resolved. This confirmed the diagnosis of drug-induced Sweet's syndrome, with clozapine as the offending agent. His mental state stabilised on an alternative antipsychotic.