People with moderate to severe mental illness have higher rates of somatic comorbidities and premature mortality than the general population (1, 2). Factors such as individual vulnerability, an unhealthy lifestyle, a poor diet, a lack of exercise, and sedentary behavior (3, 4), in addition to the use of new atypical antipsychotics as first-line therapy (5, 6), may lead to the rapid onset of weight gain (7). Recent studies in this field have reported that weight gain is only the beginning of a series of comorbidities such as metabolic disorders, metabolic syndrome (MetS), and premature cardiovascular complications (8, 9). The short-term consequence is poor adherence to treatment (10), while the medium-to-long-term consequences include physical or mental discomfort, impaired quality of life, and decreased life expectancy compared to the general population (11).

New evidence suggests that balanced dietary habits, physical activity (PA), and other lifestyle modifications may modulate brain function and promote changes in adaptive neural plasticity (12). In an incidence study (NEMESIS), it was observed that patients with mental illness who engaged in regular PA were more likely to recover from their illness compared to their counterparts who did not exercise (13), and the patients had enhanced mental capacity and cognitive function (14, 15). There is biological plausibility that exercise may have anti-inflammatory effects (16), and that PA allows for improvements in functional ability, cardiorespiratory fitness, and overall physical health (17). Lifestyle and behavioral interventions were demonstrated to be effective in reducing weight after 18 months in a large-scale study of obese individuals with severe mental illness (18). Weight loss can be achieved by combining an appropriate exercise program with healthy eating behaviors rather than by dietary restriction alone (19, 20). The involvement of a qualified professional in exercise interventions for a population of 594 patients with schizophrenia, with a mean age of 37.2 years, was observed to be significantly associated with lower dropout rates, higher-intensity physical activity, and improved adherence to treatment and group cohesion (21).

Psychiatric disorders usually begin during adolescence and early adulthood (6). The neurobiological etiology of the positive impact of PA on the psychiatric symptoms of schizophrenia remains unclear (22). However, the prevalence of excess body fat may be up to four times higher in this population than in the general population (mean age: 41 years) (23). This is especially true in patients with first-episode psychosis with a mean age of 22.2 years, as reported in an early intervention study, in whom providing information about diet and exercise may not be sufficient to prevent weight gain; thus, the need to implement effective lifestyle and life skills interventions as routine care from the beginning of treatment in young people with severe mental illness is crucial (24). Similarly, a randomized control study observed better weight management in the intervention group (behavioral interventions, diet, and exercise) within the first 3 months following the introduction of atypical antipsychotics in drug-naïve first-episode psychotic patients. These results were confirmed in a 14-week aerobic interval training program in 25 male subjects, aged 18–35 years, following their first episode of psychosis. The authors observed the effectiveness of aerobic training in reducing weight and waist circumference while improving maximal oxygen uptake (38% increase in VO₂ max and a 9 bpm decrease in resting heart rate) (25).

Furthermore, several clinical studies have investigated PA programs and suggested that exercise can relieve both depressive and anxiety disorders. An association between depression, sedentary behavior, and lack of PA has previously been reported (26). Based on 23 randomized controlled trials comparing physical exercise with different conditions (usual care, waiting lists, or no intervention), this meta-analysis showed that exercise had a moderate to large and significant effect on depressive symptoms in adult participants aged 18 and older compared with usual care and the control group, but the effect was not significant compared with psychological treatment and medication (27). A 12-week moderate-intensity exercise intervention showed a positive effect, with a reduction in symptoms and severity of anxiety and an increase in overall well-being. Cardiorespiratory fitness improved over a relatively short period in 15 patients suffering from obsessive-compulsive disorder (28). These results were in line with a randomized controlled trial that reported that anxiety decreased in the intervention group benefiting from PA and a sedentary lifestyle increased the risk of developing anxiety with cognitive and psychosocial changes in 39 young adults with anxiety aged 18–35 years in a 2-week program (1 week sedentary and 1 week PA with a pedometer) (29).

Finally, a group-based program should improve medium-to-long-term adherence to healthy habits, resulting in better compliance with appropriate psychotropic treatment, better quality of life, prevention of weight gain, and metabolic and cardiovascular outcomes (30).

It is challenging in clinical psychiatric practice to focus on improved physical and mental health conditions; however, we believe that it is crucial to investigate the effects of a multidisciplinary, group-based program aimed at improving the physical, nutritional, and mental well-being of young patients suffering from psychiatric disorders. Based on the current knowledge of the positive effects of regular PA on anxiety, depression, and psychotic symptoms, the 4-F program was established in the psychiatric department (PD) of the University Hospitals of Geneva, focusing on physical activity, education on healthy eating, and improved body perception and emotion regulation (20, 31).

In addition, we recently conducted a scientometric analysis of PA, mental health, and well-being to evaluate key themes and trends over the past decades. Our results strengthen and expand the central role of physical activity in public health and call for an optimization of the implementation of physical activity in health policies (32).

We can therefore assume that such an intervention can prevent weight gain and improve mental and physical health in young patients aged 18–35 years with severe psychiatric disorders. On this basis, we conducted a pilot study with a naturalistic design to investigate the effect of a group-based intervention.

A pilot study was conducted to explore the feasibility of the 4-F program as a real-world intervention. A total of 24 outpatients suffering from moderate to severe psychiatric disorders completed the 8-week intervention. Despite the limited sample size, a significant improvement in muscular endurance and coordination and an increase in general mental well-being were observed in these patients from baseline to T1, while depression scores slightly decreased in the 8-week program. Meanwhile, no significant decreases in weight, BMI, or body composition were observed. Only the subgroup of patients suffering from psychosis showed a slight decrease in the abdominal circumference (AC). A slight change in eating behavior was observed over time, with a tendency towards a decrease in the TFEQ hunger scores.

Patients who completed the 8-week program improved muscular endurance and coordination, with no change in flexibility or whole-body balance. In line with previous reports (43), the Eurofit test battery was used to evaluate physical fitness parameters in patients with schizophrenia or schizoaffective disorder. Both groups of patients had impaired speed of limb movement, strength, and abdominal muscular endurance compared to the healthy controls. This demonstrates that patients with psychiatric diseases have poor physical performance, exacerbated by unhealthy lifestyle habits, diet, and sedentary behavior; in addition, increasing illness duration may be a strong correlate of performance on several Eurofit test items. Possible reasons for the association of poorer physical fitness with longer illness duration include the cumulative long-term effect of poor health behaviors such as physical inactivity in patients who often suffer from psychomotor slowing. The Eurofit test may also be a valuable tool for evaluating physical fitness in inpatients with bipolar disorder, as some authors have reported significant correlations between Eurofit test items and age, illness duration, body mass index, smoking behavior, mean daily lithium dosage, and depressive and lifetime hypomanic symptoms (44).

In the 4-F program, a deliberate choice was made regarding the dosage of exercise. An 8-week group-based intervention was implemented following the recommendations of the World Health Organization (WHO) and the American College of Sports Medicine (ACSM) (45). The program consisted of two sessions per week, each lasting 60 min. One session included progressive, moderate-intensity aerobic exercise, while the other included ball team sports. It is worth noting that in the recent literature, various exercise groups have been studied, ranging in duration from 2 to 52 weeks (29, 46), with an average of 12 weeks (47). Session duration ranged from 10 to 90 min, with an average of 60 min, and frequency ranged from one to four times per week (48, 49). The quality and intensity of the physical activity varied, and it included low-intensity exercise (such as yoga or similar), moderate-intensity exercise (50), and moderate-to-vigorous intensity exercise (aerobic training) (51).

Despite some discrepancies in methodological design, these interventions had a real impact on the physical and mental health of patients suffering from severe psychiatric disorders.

It appears crucial to address their motivation for non-adherence with behavioral and motivational counseling (52).

An improvement in general mental well-being from baseline to post-intervention and a slight positive change in depression scores were observed in the 8-week program, while no difference in positive or negative scores on the PANSS was noted. This is in line with a previous 12-week program consisting of moderate-to-intense aerobic PA in which the authors observed enhanced cardiorespiratory fitness, well-being, and reduced psychiatric symptoms (53). In a longer 12-week randomized controlled study with PA interventions on first-episode psychotic patients, the authors reported a decrease in positive symptoms of PANSS and overall psychopathology. Additionally, exercise was found to be protective against the increase in negative scores observed in the control group (54).

This is consistent with a randomized control study that reported better weight management in the intervention group (behavioral interventions, diet, and exercise) in drug-naïve patients with first-episode psychosis in the first three months following the introduction of atypical antipsychotic drugs compared to a control group (55).

Not surprisingly, in the final sample of this study, 79.2% of the subjects were overweight or obese, and the prevalence of MetS was 37.5%. In the general population, this constellation of risk factors has been associated with the development of cardiovascular disease (56). This result is consistent with the results of a previous meta-analysis (57), which found that almost one in three unselected patients with schizophrenia met the criteria for MetS, and a study of bipolar and unipolar depressed patients who had a higher prevalence of MetS and BMI (BD = 46.9% vs. MDD = 35.1%, vs. general population = 22.1%) compared to the population sample (58). A recent meta-analysis showed that the prevalence of MetS in 18-year-old subjects with depression was 31.8% (59). This was in contrast to previous work conducted in 2009, wherein in a cohort of 153 psychotic patients, 46.4% were overweight or obese, while only 19% of them had MetS (19). These results indicate that before encouraging individuals with psychiatric disorders and who are overweight to increase their PA levels, it is essential to quantify their physical health and low PA levels. It is also important to establish a realistic and gradually attainable objective with them in terms of frequency, intensity, and duration of the exercises (60). The American College of Sports Medicine (ACSM) has defined the recommended exercise dosage, taking into account the frequency, intensity, time, and type of exercise as determinants of dosage (45).

Interestingly, for this cohort, no significant decrease in weight, BMI, WC, or body composition was observed. This may be due to the short duration of the program, the low participation rate, and the characteristics of the population studied (most of them were overweight or obese with multiple diagnoses).

In contrast, in an 18-month controlled study, the active group with a weight control program that included an educational activity significantly reduced their body weight and WC (61). In fact playing a team sport requires anticipation and speed to understand the actions of team members (22). This is consistent with previous reports from a 12-week randomized controlled study on psychotic patients, where the authors found no change in BMI after the PA intervention (53). In addition, a previous report of patients with first-episode psychosis who completed a 14-week aerobic interval training program found improved metabolic outcomes and cardiorespiratory fitness after the intervention, although their clinical status remained moderately to severely symptomatic and functionally impaired (25). Meanwhile, depression scores decreased slightly in the 8-week program. Several clinical studies have investigated PA programs for mood disorders and suggested that exercise can alleviate both depressive and anxiety disorders (62).

However, in this study, only the subgroup of patients suffering from psychosis had a slight decrease in the abdominal circumference (AC) after 8 weeks of the program. These results were confirmed in a 14-week aerobic interval training program with 25 individuals with a first psychotic episode. The authors observed the effectiveness of aerobic training in reducing weight and waist circumference while also improving maximal oxygen uptake (25). In the 14-week AIT study, greater WC reduction and weight loss were reported, whereas in a previous study, it took 12–18 months and 3–6 months, respectively, to obtain the same magnitude of reduction in WC and weight (61).

This suggests that AIT may induce a faster reduction in WC than traditional exercise training in a psychiatric population, as has been demonstrated in the general population (54). However, psychiatric population characteristics, such as lack of motivation or psychomotor slowing, should be considered when implementing a progressive intensity dosage.

No improvement in patients' VO₂ max was observed at the end of the program, whereas other authors reported a significant increase in VO₂ max in a 14-week aerobic interval training (AIT) program (25). This result was confirmed in patients with metabolic syndrome, where VO₂ max increased more after AIT than after moderate continuous training after 16 weeks and was associated with the elimination of more risk factors constituting the metabolic syndrome (54). In a 4-week, randomized, single-blind, controlled clinical trial in 57 patients with depression who received add-on aerobic exercise or no activity, the authors reported that VO₂ max and O2 pulse parameters increased over time only in the exercise group and remained unchanged in the control group (63).

In this 8-week intervention, there was no significant improvement in laboratory parameters (lipid profile or fasting glucose) over time, as in a previous controlled study of an exercise and dietetic program conducted in young patients with first-episode psychosis (24). Since the onset of the disease represents a critical period to prevent side effects and metabolic morbidities, it is crucial to implement effective lifestyle habits and acquire life skills through multidisciplinary training as routine care and include them in their routine care (as quickly as possible from the onset of the disease) from the initiation of treatment in young patients with serious mental diseases (24). This result must take into account that most of the patients had at least one psychotropic treatment (87.5%, and 54.2% benefited from an antipsychotic one), which differs from prior reports that observed blood lipid or glucose dysregulations when the patient was under atypical AP (64).

Interestingly, a slight decrease in the TFEQ hunger score was observed from baseline to post-intervention at T1, in line with previous works, which reported that the TFEQ disinhibition and hunger scores increased according to body mass index (19). PA may represent a valuable factor and predictor to help change the physiological imbalances caused by several psychiatric disorders and unhealthy lifestyles (65). There is evidence that exercise may influence the drive to eat through the modulation of hunger (66).

Finally, the effects of the 4-F program on clinical global impression (gravity and improvement) did not differ after 4 weeks of intervention, in line with a previous study showing that improvements on the Calgary Depression Scale (CDS) in both yoga and aerobic exercise groups at 3 months of intervention remained stable at 18 months of follow-up in both intervention groups (67).

The results of this pilot study demonstrate the feasibility of the 4-F program in assessing 8 weeks of adapted physical activity levels and improvements in muscular endurance and coordination in young patients with moderate-to-severe psychiatric disorders. Additionally, it highlights a notable increase in the overall mental well-being of these patients.

However, there are some limitations to this study. First, the hypotheses could not be tested due to a lack of adequate power and sample size calculations.

Second, the study was non-randomized and non-controlled due to the absence of an active control group. Nevertheless, the effect of a specific 8-week program on mental and physical outcomes was evaluated in an outpatient setting with a 4-week follow-up.

Third, the longitudinal analyses were conducted on a small sample size of participants; therefore, the results and conclusions should be regarded as preliminary and do not allow for definitive conclusions to be drawn. The dropout rate reached the upper limit of the range reported in previous findings [20 to 50% in outpatients (41)], and there were occasional missing data in some items of the scale, which could be attributed to multiple parameters. These include a lack of motivation and attrition due to the mental disease itself, outpatient inclusion, the COVID-19 outbreak with the subsequent quarantine periods, the low priority given to physical activity by psychiatrists, and other barriers that hindered engagement in the exercise program, such as the organization of daily routines (68). In addition, no significant differences were found when comparing the dropout rates between the three diagnosis groups. Response to physical activity was highly individualized, making it difficult to satisfy everyone. Creative ways, optimized motivation, and daily practice activities to improve mobility, coordination, and strength (to develop motor skills) are needed to monitor and enhance adhesion and compliance in this population (69, 70).

Finally, the Eurofit test as a speed of limb movement by plate tapping is expected to have a large learning effect when performed for a second time, so these preliminary results should be interpreted with caution (40, 43). Despite these limitations, several results indicate that an innovative program is feasible and can lead to an effective improvement in muscular endurance and coordination, increasing well-being over time. Moreover, this pilot study was conducted with a pragmatic and real-world approach, aiming to be more inclusive in terms of diagnosis, initiation of exercise, promotion of physical health, encouragement of healthy lifestyle habits, and prevention of weight gain and metabolic dysfunction.

The feasibility of this program will help us implement and develop a structured research plan, considering a larger cohort of patients with a control group, to strengthen our methodology and obtain strong results.

Despite the acknowledged limitations, these preliminary findings suggest that the implementation of an 8-week group-based program may be feasible and may lead to potential increases in muscular endurance and coordination, along with improvements in the general mental well-being of patients compared to baseline. This pilot study has the potential to guide the refinement of procedures to foster better patient involvement and adherence to the program, thus potentially reducing dropout rates. It also suggests the benefits of a multidisciplinary approach that focuses on both physical and mental health.

Additionally, the outcomes of this study provide a rationale for initiating subsequent longitudinal follow-up research in a larger and more controlled cohort of patients. Such extended investigations could significantly advance the understanding of these interventions, which have already shown promise in improving the quality of life and reducing morbidity and mortality in individuals dealing with severe mental illnesses.