This epidemiological study examined demographic characteristics of patients with schizophrenia and schizoaffective disorder eligible for paliperidone treatment. It explored illness phase, core symptoms, psychosocial functioning, treatment patterns, and prescribing rationale, while also assessing the impact of the COVID-19 pandemic on primary therapy. Article was published in VICEVERSA in 2025.

Peter Pregelj, Breda Barbič-Žagar, Kirill Chernousov, Maja Badovinac

Key words

paliperidone, schizophrenia, schizoaffective disorder, psychosocial functioning

Abstract

Introduction: The epidemiological research investigated demographic data on patients with schizophrenia and schizoaffective disorder eligible for treatment with paliperidone, the phase of the illness and its main symptoms, psychosocial functioning, treatment regime, and reasons for prescribing paliperidone. The research also assessed the impact of COVID-19 pandemic on the primary treatment.

Method: Observational, multicentric, epidemiological research, which included 207 patients with schizophrenia or schizoaffective disorder in whom treatment with paliperidone was indicated in regular clinical practice in compliance with the Summary of Product Characteristics (SmPC). A single data capture was conducted. Data on 194 patients were used in the statistical analysis. Due to incomplete data, 13 patients were not considered in the analysis.

Results: At inclusion, 143 patients were diagnosed with schizophrenia and 51 with schizoaffective disorder. 58% of all patients were single, 29% were employed, 21% had suicidal thoughts, and 16% reported psychoactive substance abuse. Patients had impaired psychosocial functioning: moderately to severely impaired functioning or inability to function was reported by 67% of patients with schizophrenia and 65% of patients with schizoaffective disorder. A combination of antipsychotics was administered to 50% of patients with schizophrenia and 64% of those with schizoaffective disorder. Psychiatric comorbidity was present in 19% of patients. Over the last year, 80% of patients had received pharmacological treatment. 62% of patients did not reach remission. Main reasons for the discontinuation of previous pharmacological treatment were ineffective treatment, poor adherence, and poor psychosocial functioning. Main reasons for the initiation of treatment with paliperidone were expected improvement of positive symptoms, ineffective previous treatment, and expected favourable impact on patient’s psychosocial functioning.

Conclusions: The results showed a diminished quality of life of patients with schizophrenia and schizoaffective disorder. Over 60% of patients had at least moderately impaired psychosocial functioning, and only a small percentage of patients were employed or married. Patients were mostly treated with a combination of antipsychotics. Main reasons for the initiation of treatment with paliperidone prolonged-release tablets were expected improvement of positive symptoms, ineffective previous treatment, and expected favourable impact on psychosocial functioning.

Introduction

Schizophrenia and schizoaffective disorder are two of the most severe mental disorders. They
impact a patient’s perception, thoughts, emotions and behaviour. In both, patients experience
positive, negative, cognitive and affective (mood) symptoms (symptoms of mania, depression and/
or anxiety), though these are even more frequent and more pronounced in schizoaffective disorder.
(1, 2) It was once believed that schizophrenia has a worse prognosis than schizoaffective disorder.
However, cognitive functioning seems to be similarly impaired in patients with schizoaffective
disorder as in those with schizophrenia. (3, 4) Actually, cognitive functioning is one of the major
indicators of how a person with a psychotic disorder will function in the society. (5, 6)

Other concomitant mental disorders that impact patients with schizophrenia and schizoaffective
disorder are also common. (7, 8) The COVID-19 pandemic was an additional factor contributing
to the occurrence of mental disorders. It was then associated with increased incidence of mental
distress, insomnia, anxiety and depression, as well as some other mental disorders. (9)

One of the long-term goals of the treatment of patients with schizophrenia and schizoaffective
disorder is to restore the patient’s functioning to the level it was before the disease. Symptom
improvement does not always bring improvement of everyday functioning. Cognitive and negative
symptoms tend to persist in spite of the treatment. Full remission and functioning are impossible to
achieve in some cases, yet the treatment should aim to improve both. (10, 11)

Several antipsychotics are indicated for the treatment of both disorders. They differ in their binding affinity to receptors, pharmacokinetic and pharmacodynamic properties, and accordingly, efficacy in relieving different symptom groups. Paliperidone prolonged-release tablets are the only atypical antipsychotic approved in Europe for the treatment of schizophrenia in adults and adolescents 15 years of age and older, and schizoaffective disorder in adults. (12–14)

The epidemiological research investigated demographic data on patients with schizophrenia and schizoaffective disorder eligible for the treatment with paliperidone. The research defined the phase of the illness and its main symptoms, psychosocial functioning, treatment regime, and reasons for prescribing paliperidone tablets.

Methods

The observational, multicentric, epidemiological research conducted in Slovenia between
May 2022 and March 2023 included patients with schizophrenia or schizoaffective disorder in whom
treatment with paliperidone was indicated. It was carried out in compliance with the Declaration
of Helsinki, national legislation, study protocol and the Slovenian Code of Medical Ethics. The
research was approved by the Medical Ethics Committee of the Republic of Slovenia (14.12.2021)
and was notified to the Agency for Medicinal Products and Medical Devices of the Republic of
Slovenia (02.02.2022).

The research included patients of both genders, older than 18 years, diagnosed with schizophrenia
or schizoaffective disorder in whom treatment with paliperidone was indicated in compliance with regular clinical practice and the summary of main product characteristics (SmPC). A one time data collection from regular clinical practice was planned for every patient. Doctors collected demographic data, data on psychoactive substance abuse, employment status and marital status, psychosocial assessment as well as suicide risk, and primary diagnosis. Data collection in the research included data on the phase of the disorder, its manifestations, duration of the illness, treatment at the time of the visit, remissions and treatment continuation. In addition, it included reasons for the treatment with paliperidone, data on possible change of the primary diagnosis, patient adherence, concomitant mental disorders and their treatment, data on any complications or deterioration of the health condition due to measures adopted during the pandemic or due to COVID-19, and data on COVID-19 infection and recovery.

The research involved 46 investigators from different investigational sites and included 207 patients. Data on 194 patients were used in the statistical analysis. Due to incomplete data, 13 patients were not considered in the analysis. Calculations were made using Microsoft Office® Excel 2019.

Results

Patients
The mean age of patients included was 45.5 ± 14.3 years. There were more men (58.2%) than
women (41.2%). Gender of one patient was not recorded. Schizophrenia was the diagnosis in
143 patients and schizoaffective disorder in 51 patients. The investigators changed the diagnosis in
only 8.2% of patients during the visit. The diagnosis was given more than 5 years earlier to more
than 64% of patients. Most of patients who were already treated with paliperidone before inclusion
were diagnosed more than 10 years ago. Fewer patients than one third (29.4%) were married or
lived in cohabitation, 58.2% were single, 8.2% divorced and 4.1% widowed.

Most patients were retired. 49.5% of patients were receiving a disability pension and 11.3% had a
status of a retired person. One third of patients were employed, of them 16.5% full time, 4.1% part
time, 1.5% were self-employed, 7.2% were temporarily employed, and 1% had a farmer status.
3.1% were students and 5.7% of patients were unemployed.

The majority of patients (84.5%) did not abuse psychoactive substances, while 15.5% of patients
abused one or more than one psychoactive substance. More than a half abused illicit drugs, half of them smoked tobacco and abused alcohol, while 6.7% abused other psychoactive substances. Out of all, 21.1% of patients were at suicidal risk.

Phases and symptoms of psychotic disorder
Among patients with schizophrenia, only 16.8% reached the maintenance phase with full remission.
Most patients went through an acute or subacute phase of the disease (42.7%) or maintenance phase
with partial remission (40.6%). Data on the percentage of patients treated before with paliperidone is stated for each phase (Figure 1). Maintenance phase with full or partial remission was achieved in 62.0% of patients treated with paliperidone and in slightly fewer patients who were not treated with paliperidone (55.7%).

Patients with schizoaffective disorder were mostly in a mixed, manic or depressive phase of the
disease (25.5%, 21.6% or 17.6%). Only 11.8% of patients were in the maintenance phase with full
remission. Here too, patients were distributed with regard to the medication they were taking in
the previous treatment (Figure 2). Maintenance phase with full or partial remission was achieved
in 55.5% of patients in the group of patients treated with paliperidone, which was more than in the
group of patients treated with another medicine (30.9%).

Positive symptoms were the most frequently expressed symptoms in both diseases – in 89.5% of
patients with schizophrenia and 76.5% of patients with schizoaffective disorder. More than half of
patients with schizophrenia also reported on negative and cognitive symptoms. More than one half of patients with schizoaffective disorder reported on manic symptoms and depression symptoms, and 40% reported also on cognitive and negative symptoms (Figure 3).

Psychosocial functioning assessment
Investigators assessed psychosocial functioning based on a 7-stage scale.
1 – Very good functioning in various activities
2 – Good functioning, only occasional minor problems
3 – Slightly reduced functioning in certain areas, keeping some important relationships
4 – Moderately reduced functioning in certain areas with the possibility of conflict, a few friends
5 – Severely reduced functioning in several areas, no friends, serious problems with responsible
behaviour
6 – Inability to function in almost all areas, social isolation
7 – Inability to maintain social functioning and minimal personal hygiene

Psychosocial functioning was at least moderately reduced in 66.5% of patients with schizophrenia
and 64.7% of patients with schizoaffective disorder. Only 11.9% of patients with schizophrenia and
17.6% of patients with schizoaffective disorder were functioning well or very well (Figure 4).

Previous pharmacological treatment
In the year before they were included in the research, 80.4% of patients received pharmacological treatment. Most patients were treated with more than one medicine. Antipsychotics were the most usual treatment in both disorders, with additional antidepressants prevailing in schizophrenia and mood stabilisers in schizoaffective disorder (Figure 5)

Drugs of the first choice among antipsychotics for the treatment of the primary disorder before the trial
were paliperidone, olanzapine and risperidone. Among the patients diagnosed with schizophrenia
and schizoaffective disorder who were treated before the trial, 24% were taking paliperidone. Table 1 shows collected particularities about the duration and way of taking medicines.

Olanzapine was the treatment in 23.7% of patients and risperidone in an equal proportion of patients.
On average, the previous treatment with olanzapine lasted for 5.15 years and with risperidone 4.7
years. The average daily dose of olanzapine tablets taken by patients was 14.46 mg. Most patients
were taking risperidone tablets at an average daily dose of 4.56 mg, while three patients were taking
risperidone oral solution at an average daily dose of 5.33 mg.

Of all patients comprised in the statistical analysis, 45.5% were taking an antipsychotic as monotherapy and 53.8% of all patients were taking it in combination with other medicines. The information about one patient with schizoaffective disorder was not recorded. Treatment with more medicines was more common in patients with schizoaffective disorder (Figure 6).

Among the most commonly chosen medicines for the treatment of the primary disorder were:
antidepressant sertraline at an average daily dose of 106.67 mg, anxiolytic lorazepam at an
average daily dose of 2.03 mg, mood stabiliser lamotrigine at an average daily dose of 161.11 mg,
anticholinergic biperiden at an average daily dose of 3.75 mg, and hypnotic zolpidem at an average
daily dose of 5.00 mg. The graph shows the most commonly prescribed active substances (Figure 7).

Investigators assessed complete adherence in 55.1% of all included patients and partial adherence
in 38.5%, while in 6.4% they assessed nonadherence (Figure 8).

Pharmacological treatment one year before inclusion in the research did not achieve remission in 62.2% of patients. Remission was achieved in only 35.0% of patients with schizophrenia and 46.2% of those with schizoaffective disorder (Figure 9).

Psychiatric comorbidity was present in 18.6% of patients. More than half of these patients (58.3%)
were receiving pharmacological therapy for their treatment. Most of them (66.7%) were treated
with antidepressants, 23.8% with antipsychotics and 9.5% with anxiolytics. None of these patients
was treated with mood stabilisers, anticholinergics, hypnotics or sedatives.

Withdrawal of previous pharmacological treatment
During the visit of data collection for the research, medication was withdrawn in 60.3% of patients
who were pharmacologically treated during the previous year. They were withdrawn for various
reasons, and investigators could select several. The most common cause was inefficacy, poor patient
compliance and poor psychosocial functioning (Figure 10). Percentage of the cause was calculated
with regard to patients in whom therapy was withdrawn

Reasons for introducing paliperidone
The epidemiological research revealed that there were various reasons for the introduction of
paliperidone. Investigators could choose up to three for each patient from the checklist. Main
reasons for the initiation of treatment with paliperidone regarding both disorders were expected improvement of positive symptoms, ineffective previous treatment, and expected favourable impact on patient’s psychosocial functioning. However, in patients with schizoaffective disorder the third most frequent reason was expected improvement of mood symptoms (mania and depression symptoms) (Table 2)

COVID-19 infection and recovery
One half of patients recovered from COVID-19 and in one third (32.0%) the primary mental
disorder complicated or worsened because of either epidemiological measures, e.g., social isolation and fewer visits, or because of the infection itself.

Discussion

Results of the epidemiological research revealed that 16% of patients abused psychoactive
substances, with half of them being smokers. Data from other epidemiological studies show that
there are many more smokers among schizophrenic patients, between 70% and 85%. (15) The
significant difference between this and other studies may be explained by the fact that patients have difficulty confessing their harmful habits and doctors in clinical practice need to ask right questions and be persistent to obtain precise answers. Information about smoking is important when choosing the right treatment as smoking can change the activity of liver enzymes, primarily cytochrome P450 enzyme 1A2 and some other cytochrome P450 isoenzymes that metabolise medicines. It may be necessary that smokers need higher doses of medication. Studies in the past proposed that higher doses of risperidone were required in smokers because smoking slightly stimulates metabolism of risperidone, most likely via action on cytochrome P450 enzyme 3A4. (16) Paliperidone is the active metabolite of risperidone. A study in patients treated with paliperidone indicates that paliperidone plasma concentration is not significantly affected by smoking, meaning that paliperidone is a more adequate choice in smokers as dose-adjustments may not be necessary. (17)

In this study, only 29% of patients reported they were married or lived in cohabitation, which is
comparable with other studies that state that a small proportion of all patients, about 30%, were
married. (18, 19) Only 29% of patients in this study were employed. According to data in literature,
the percentage of employed patients with schizophrenia in Norway is 10.2% and in Germany 30.3%. (20) Being employed has a significant influence on the quality of a patient’s life. As studies reveal, employment contributes to enhanced patient’s social functioning and quality of life. (21)

At least moderately reduced psychosocial functioning was characteristic in more than 60% of patients included in the epidemiological research. In a study comprising patients from 6 European centres, social functioning disorders were observed in 78% of patients with schizophrenia. It was also noted that two thirds of patients were not capable of performing basic social roles even when psychotic symptoms were in remission. (19) Improvement of (psycho)social functioning remains one of the most demanding and important goals in the treatment of the two disorders. (19, 22) Data from other studies demonstrate paliperidone efficacy in improving social functioning of patients. A two-month non-interventional study in 153 patients with schizophrenia and schizoaffective disorder who were treated with Parnido (paliperidone) demonstrated a statistically significant improvement of social and work functioning of patients. (23) In one of the studies, the personal and social functioning assessed according to PSP (personal and social performance scale) has improved by 14.5% after six weeks of treatment with paliperidone tablets in doses from 3 mg to 12 mg. (24)

Results in this study revealed that more than 20% of patients were at suicidal risk. These data
are comparable with general data showing that probability of suicide is about 10 percent in
individuals with schizophrenia. Suicide is one of the main causes for the shorter life expectancy
of individuals with schizophrenia. Demographic and psychosocial factors that increase the risk
of suicide in individuals with schizophrenia include: younger age, being male, being unmarried,
living alone, being unemployed, being intelligent, being well-educated, good premorbid adjustment
or functioning, having high personal expectations and hopes, having an understanding that life’s
expectations and hopes are not likely to be met, having had recent (i.e., within past 3 months) life
events, having poor work functioning, and having access to lethal means, such as firearms. (25)

In both disorders, antipsychotics were the most frequently prescribed therapy (96.8%), along with
antidepressants prevailing in schizophrenia and mood stabilisers in schizoaffective disorder. More
than one half of patients treated with antipsychotics were concomitantly taking more than one
antipsychotic. Data from clinical practice indicate that combinations of antipsychotics are commonly
prescribed. Among patients included in this research, 50% of patients with schizophrenia and 64% of patients with schizoaffective disorder were treated with a combination of antipsychotics. This is in line with findings of other studies that show that about half of patients with schizophrenia are treated with a combination of antipsychotics. (26) Medicines containing paliperidone, olanzapine or risperidone were the most commonly chosen antipsychotics in the research.

In the research, the percentage of patients who were treated with paliperidone and achieved full or
partial remission and the percentage of patients who achieved remission with treatment with other
medicines were compared. Paliperidone contributed to a higher rate of achieving remission, as 62% of patients with schizophrenia who were treated with paliperidone before and 56% of those who had not taken paliperidone before achieved full or partial remission. The difference is more significant in patients with schizoaffective disorder of whom 56% of patients treated with paliperidone achieved remission and only 31% of patients treated with other medicines.

In addition to the primary mental disorder, other concomitant mental disorders were present in one
fifth of patients (19%). More than one half of them were concomitantly treated with anxiolytics,
antidepressants and antipsychotics. Data in other studies also state that 15% to 50% of patients have
different concomitant mental disorders. (27)

Patient adherence remains one of the main challenges in the treatment of mental disorders particularly as patients often have no faith in the efficacy of medication, experience adverse reactions or have other subjective reasons for discontinuing the treatment. An individual approach remains essential to ensure good adherence. (28) In this research, complete treatment adherence was achieved in only 55% of patients, while partial adherence or nonadherence was seen in 45% patients. Results of this research are comparable to data from an observational study in which nonadherence of patients with schizophrenia was assessed to be 41%. (28)

Psychiatrists withdrew the previous pharmacological therapy in more than 60% of patients at the data collection visit. Reasons for the withdrawal included inefficacy of the medication (42%), poor patient compliance (34%) and poor patient functioning. Other reasons for a change reported by doctors were poor tolerance of the medication, complicated treatment regimen and many side effects. In accordance with NICE guidelines, patient decision aids and considering patient’s needs and expectations are of extraordinary importance in the selection of the antipsychotic therapy as they bring more understanding of possible benefits and adverse reactions of their medicines and add to their quality of life. (29)

Mostly, reasons for the initiation of treatment with paliperidone were expected improvement
of positive symptoms, ineffective previous treatment, expected favourable impact on patient’s psychosocial functioning, and additionally, expected improvement of mood symptoms (mania and depression symptoms) in patients with schizoaffective disorder. The results referred to are in accordance with data from other studies and an extensive meta-analysis that demonstrated high efficacy of paliperidone in the management of positive symptoms, improvement in the quality of life and social functioning of patients. (30)

Doctors prescribed paliperidone prolonged-release tablets for the treatment of schizophrenia at an
average daily dose of 5.9 mg which was in accordance with the medicine’s SmPC that recommends a dose of 6 mg once daily in the morning in adult patients with schizophrenia. (14) Smaller average daily doses as recommended in the medicine’s SmPC for treating schizoaffective disorder were used in the research (3.9 mg). (14) The difference could be explained with the high rate of antipsychotic combinations used in those cases (64%).

Conclusion

The epidemiological research offered a more precise insight into the regular clinical practice
(real-world evidence research) in the treatment of patients with schizophrenia and schizoaffective
disorder eligible for the treatment with paliperidone. Results indicate that the quality of life is
worse in patients with schizophrenia. The majority of patients had at least moderately impaired
psychosocial functioning, and only a small percentage of patients were employed or married.
Patients were mostly treated with a combination of several antipsychotics. Main reasons for the
initiation of treatment with paliperidone prolonged-release tablets were expected improvement of
positive symptoms, ineffective previous treatment, and expected favourable impact on psychosocial
functioning. An individual approach was essential in selecting the therapy and it included the
doctor’s clinical decision along with considering a patient’s needs and expectations.

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Authors

Prof. Peter Pregelj, MD, Spec Psych, PhD
University Psychiatric Clinic Ljubljana

Breda Barbič-Žagar, MD
Krka, d. d., Novo mesto, Slovenia

Kirill Chernousov, MD
Krka, d. d., Novo mesto, Slovenia

Maja Badovinac
Krka, d. d., Novo mesto, Slovenia

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Published: January 2026