The (im?)possibility of a biological substrate for mental disorders

ACHTERGROND Er bestaat een tegenstelling tussen de ‘medische’ kijk op een psychiatrische aandoening (als gegevenheid van de natuur in de zin van een biologisch substraat) en de constructivistische visie. DOEL Onderzoeken hoe de constructivistische positie zich verhoudt tot deze medische kijk op psychiatrische aandoeningen. METHODE Een beschouwing gebaseerd op een conceptuele analyse, met name van het boek The social construction of what? (1999) van de Canadese wetenschapsfilosoof Ian Hacking. RESULTATEN Er blijken verschillende objecten van constructivistische analyses een rol te spelen bij psychiatrische aandoeningen, de aandoening zelf en het idee of concept van de aandoening. Deze verschillende objecten interacteren daarbij ook nog met elkaar. Deze interacties kunnen expliciet gemaakt worden door indifferente soorten te onderscheiden van interactieve soorten. Zo wordt duidelijk dat als een aandoening niet gedetermineerd wordt door een biologisch substraat, dit niet automatisch betekent dat zo’n aandoening geheel losstaat van een mensonafhankelijke natuur. CONCLUSIE Hackings filosofie biedt de mogelijkheid om voorbij te gaan aan de tegenstelling tussen de constructivistische positie en de medische kijk op psychiatrische ziekten. BACKGROUND: The constructivist position is often used for psychiatric diseases, in contrast with the general medical view. In the medical view a biological substrate is decisive for a classification as 'disease', which is not the case in the constructivist position. AIM: We investigate how both positions relate to each other in psychiatric diseases. METHOD: Analysis based on a conceptual analysis of Ian Hacking's book The Social Construction of What? (1999). RESULTS: Different objects ought to be distinguished in a constructivist analysis of psychiatric diseases; the disease itself and the idea or concept of that disease. These different objects interact with each other. These interactions can be made explicit by distinguishing interactive kinds from indifferent kinds. Doing so makes it clear that even if a disease is not determined by a biological substrate, this does not imply that a biological substrate is something completely separate from that disease. CONCLUSION: Hacking's philosophy makes it possible to move beyond the opposition between the medical and the constructivist account of psychiatric diseases by combining both accounts

Effects of an 18-week exercise programme started early during breast cancer treatment: a randomised controlled trial

Background: Exercise started shortly after breast cancer diagnosis might prevent or diminish fatigue complaints. The Physical Activity during Cancer Treatment (PACT) study was designed to primarily examine the effects of an 18-week exercise intervention, offered in the daily clinical practice setting and starting within 6 weeks after diagnosis, on preventing an increase in fatigue. Methods: This multi-centre controlled trial randomly assigned 204 breast cancer patients to usual care (n = 102) or supervised aerobic and resistance exercise (n = 102). By design, all patients received chemotherapy between baseline and 18 weeks. Fatigue (i.e., primary outcome at 18 weeks), quality of life, anxiety, depression, and physical fitness were measured at 18 and 36 weeks. Results: Intention-to-treat mixed linear model analyses showed that physical fatigue increased significantly less during cancer treatment in the intervention group compared to control (mean between-group differences at 18 weeks: -1.3; 95 % CI -2.5 to -0.1; effect size -0.30). Results for general fatigue were comparable but did not reach statistical significance (-1.0, 95% CI -2.1; 0.1; effect size -0.23). At 18 weeks, submaximal cardiorespiratory fitness and several muscle strength tests (leg extension and flexion) were significantly higher in the intervention group compared to control, whereas peak oxygen uptake did not differ between groups. At 36 weeks these differences were no longer statistically significant. Quality of life outcomes favoured the exercise group but were not significantly different between groups. Conclusions: A supervised 18-week exercise programme offered early in routine care during adjuvant breast cancer treatment showed positive effects on physical fatigue, submaximal cardiorespiratory fitness, and muscle strength. Exercise early during treatment of breast cancer can be recommended. At 36 weeks, these effects were no longer statistically significant. This might have been caused by the control participants' high physical activity levels during follow-up

Efficacy of a multi-component intervention to reduce workplace sedentary behaviour in office workers

Objective: To investigate the efficacy of a work-based multicomponent intervention to reduce office workers’ sitting time. Methods: Offices (n=12; 89 workers) were randomised into an 8-week intervention (n=48) incorporating organisational, individual, and environmental elements or control arm. Sitting time, physical activity and cardiometabolic health were measured at baseline and after the intervention. Results: Linear mixed modelling revealed no significant change in workplace sitting time, but changes in workplace prolonged sitting time (-39 min/shift), sit-upright transitions (7.8 per shift) and stepping time (12 min/shift) at follow-up were observed, in favour of the intervention group (p<0.001). Results for cardiometabolic health markers were mixed. Conclusions: This short multicomponent workplace intervention was successful in reducing prolonged sitting and increasing physical activity in the workplace, although total sitting time was not reduced and the impact on cardiometabolic health was minimal.

The effectiveness and cost-effectiveness of strength and balance Exergames to reduce falls risk for people aged 55 years and older in UK assisted living facilities: A multi-centre, cluster randomised controlled trial

Background: Falls are the leading cause of fatal and non-fatal unintentional injuries in older people. The use of Exergames (active, gamified video-based exercises) is a possible innovative, community-based approach. This study aimed to determine the effectiveness of a tailored OTAGO/FaME based strength and balance Exergame programme for improving balance, maintaining function and reducing falls risk in older people. Methods: A two-arm cluster randomised controlled trial recruiting adults aged 55 years and older living in 18 assisted-living (sheltered housing) facilities (clusters) in the UK. Standard care (physiotherapy advice and leaflet) was compared to a tailored 12-week strength and balance Exergame programme, supported by physiotherapists or trained assistants. Complete-case analysis (intention to treat) was used to compare Berg Balance Scale (BBS) at baseline and at 12 weeks. Secondary outcomes included: fear of falling, mobility, falls risk, pain, mood, fatigue, cognition, healthcare utilisation and health-related quality of life; self-reported physical activity and falls. Results: Eighteen clusters were randomised (9 to each arm) with 56 participants allocated to the intervention and 50 to the control (78% female, mean age 78 years). Fourteen participants withdrew over the 12 weeks (both arms), mainly for ill health. There was an adjusted mean improvement in balance (BBS) of 6.2 (95% CI 2.4 to 10.0), reduced fear of falling (p=0.007) and pain (p=0.02) in Exergame group. Mean attendance at sessions was 69% (mean exercising time of 33 minutes/week). 24% of control group and 20% of Exergame group fell over trial period. The change in falls rates significantly favoured the intervention (incident rate ratio 0.31 (95% CI 0.16 to 0.62, p=0.001)). The point estimate of the incremental cost effectiveness ratio (ICER) was £15,209.80 per QALY. Using 10,000 bootstrap replications, at the lower bound of the NICE threshold of £20,000 per QALY, there was a 61% probability of Exergames being cost-effective, rising to 73% at the upper bound of £30,000 per QALY. Conclusions: Exergames, as delivered in this trial, improve balance, pain and fear of falling and are a cost-effective fall prevention strategy in assisted living facilities for people aged 55 years or older

Effects and moderators of exercise on quality of life and physical function in patients with cancer:An individual patient data meta-analysis of 34 RCTs

This individual patient data meta-analysis aimed to evaluate the effects of exercise on quality of life (QoL) and physical function (PF) in patients with cancer, and to identify moderator effects of demographic (age, sex, marital status, education), clinical (body mass index, cancer type, presence of metastasis), intervention-related (intervention timing, delivery mode and duration, and type of control group), and exercise-related (exercise frequency, intensity, type, time) characteristics. Relevant published and unpublished studies were identified in September 2012 via PubMed, EMBASE, PsycINFO, and CINAHL, reference checking and personal communications. Principle investigators of all 69 eligible trials were requested to share IPD from their study. IPD from 34 randomised controlled trials (n=4,519 patients) that evaluated the effects of exercise compared to a usual care, wait-list or attention control group on QoL and PF in adult patients with cancer were retrieved and pooled. Linear mixed-effect models were used to evaluate the effects of the exercise on post-intervention outcome values (z-score) adjusting for baseline values. Moderator effects were studies by testing interactions. Exercise significantly improved QoL (β=0.15, 95%CI=0.10;0.20) and PF (β=0.18,95%CI=0.13;0.23). The effects were not moderated by demographic, clinical or exercise characteristics. Effects on QoL (βdifference_in_effect=0.13, 95%CI=0.03;0.22) and PF (βdifference_in_effect=0.10, 95%CI=0.01;0.20) were significantly larger for supervised than unsupervised interventions. In conclusion, exercise, and particularly supervised exercise, effectively improves QoL and PF in patients with cancer with different demographic and clinical characteristics during and following treatment. Although effect sizes are small, there is consistent empirical evidence to support implementation of exercise as part of cancer care