I read with great interest the recently published work by Ojagbemi et al. (Reference Ojagbemi, Bello, Owolabi and Baiyewu2020) in which the authors describe the prevalence, predictors, and association of prestroke neuropsychiatric symptoms with disability, poststroke depression (PSD), and mortality outcomes at 3 months. There is growing evidence that prior neuropsychiatric disorders constitute substantial risk factors for stroke (Barlinn et al., Reference Barlinn, Kepplinger, Puetz, Illigens, Bodechtel and Siepmann2015; Everson-Rose et al., Reference Everson-Rose2014). Depression, stress, negative emotions, anxiety, and irritability affect cardiovascular and cardiac diseases’ morbidity and mortality. Despite the conducted study, still little is known about the impact of preceding neuropsychiatric disturbances on stroke incident, outcomes, and risk. Furthermore, a lot of research has methodological limitations about prior neuropsychiatric disturbances and their association with stroke (Everson-Rose et al., Reference Everson-Rose2014). Thus, the study by Ojagbemi et al. (Reference Ojagbemi, Bello, Owolabi and Baiyewu2020) is notably desirable in this knowledge gap.

Preceding neuropsychiatric disorders can be interrelated to incident stroke. However, the researchers and medical staff consider possible confounding effects by pre-existent and cardiac and cerebrovascular diseases. Therefore, in the study, Ojagbemi et al. (Reference Ojagbemi, Bello, Owolabi and Baiyewu2020) investigated only patients who experienced a first-ever stroke. The authors made every effort to reliably assess patients. Thus, standardized tools were used in the work. Of those surveyed, 52% had neuropsychiatric symptoms before the stroke. The most common symptoms were depression – 39.3%, anxiety – 33.3%, problems with falling asleep – 27.3%, and others. In contrast, 31.3% of patients were diagnosed with PSD 3 months after the onset of stroke, meanwhile, in 42.6% of patients with depression before stroke. The major correlates of PSD included stroke severity and The Mini-Mental State Exam score. The presence of neuropsychiatric symptoms before a stroke resulted in a decrease in the results in terms of motor functioning, as well as a higher probability of death after a stroke after 3 months (Ojagbemi et al., Reference Ojagbemi, Bello, Owolabi and Baiyewu2020). The conducted meta-analyses indicate that depressive disorders increase the risk of the first-ever stroke by 40% in the general population (Barlinn et al., Reference Barlinn, Kepplinger, Puetz, Illigens, Bodechtel and Siepmann2015). It should also be emphasized that the prevalence of depression before stroke differs depending on the assessment method used. It has been proven that a clinical history suggests a higher incidence of depression before stroke than a case report or self-report. The results of meta-analyses show that depression at any point in life before a stroke increases the probability of PSD threefold (Taylor-Rowan et al., Reference Taylor-Rowan, Momoh, Ayerbe, Evans, Stott and Quinn2019). In the study by Ojagbemi et al. (Reference Ojagbemi, Bello, Owolabi and Baiyewu2020), no relationship was found between these two emotional disorders. This may result from too short period of observation of patients after stroke. Therefore, this observation should be extended. The authors are fully aware of the limitations of their study, which is correctly stated in the article. Depression may occur at any stage after a stroke – acute (up to 1 month), medium (1–6 months), and long-term (>6 months). Sometimes patients show symptoms of depressive disorders immediately after stroke. However, this may result from their acute reactive nature, which has nothing to do with a full episode of depression. Most reports treat depression as a disorder of the second or, slightly less frequently, the third of these phases. The peak incidence is 3–6 months after a stroke. After about a year, the prevalence decreases to about half of the level from the first 6 months, and after about 1 to 2 years, it returns to the baseline level (Hackett et al., Reference Hackett, Yapa, Parag and Anderson2005). That is why it is so important to extend the observation period of patients. Additionally, in a study by Caeiro et al. (Reference Caeiro, Ferro, Santos and Figueira2006), it has been proven that the prior history of mood disorders is a factor associated with the onset of PSD in the acute period after a stroke (up to 4 days). Interestingly, individual studies suggest that the presence of mental disorders even among relatives (especially depressive episodes, anxiety disorders in first-degree relatives) is another risk factor for PSD (Morris and Robinson, Reference Morris and Robinson1995; Morris et al., Reference Morris, Robinson, Raphael, Samuels and Molloy1992). It is estimated that PSD may affect nearly 50% of patients (Ayerbe et al., Reference Ayerbe, Ayis, Wolfe and Rudd2013). Understanding and thoroughly researching mood disorders prior to stroke are key to understanding the development of PSD. In addition, this acquired knowledge may help in setting treatment strategies, conducting screening, and education (Towfighi et al., Reference Towfighi2016). Nevertheless, the prevalence of depressive disorders before stroke varies from<1% to 52% (Liu et al., Reference Liu2017; Wulsin et al., Reference Wulsin2012). Moreover, PSD is believed to be the cause of slower recovery, deterioration of patients’ functioning and their quality of life below the level resulting from neurological dysfunction. What is more, PSD is also responsible for the cause of increased mortality.

The strength of the study by Ojagbemi et al. (Reference Ojagbemi, Bello, Owolabi and Baiyewu2020) is the combination of various socio-psychological characteristics and the use and estimation of the odds ratio of associations using regression analyses. The logistic regression model is widely and successfully used to identify risk factors in medical research and diagnosis. Additionally, the prestroke depressive disorder rate was estimated at 39.3%. In contrast, PSD occurred in 42.6% of stroke survivors with prestroke depression symptoms. In addition, the conducted research indicates that most cases of PSD do not result from unmasked and detected depression before stroke, nor is it a re-manifestation of previously existing disorders (Ayerbe et al., Reference Ayerbe, Ayis, Wolfe and Rudd2013).

The results obtained by Ojagbemi et al. (Reference Ojagbemi, Bello, Owolabi and Baiyewu2020) encourage further research in this area. Therefore, it would be important to increase the study group. It would also be beneficial to determine whether the severity and intensity of neuropsychiatric disorders in a particular way correlate with stroke and its long-term consequences. What is more, it is also important to conduct future research to determine the specific etiology of this relationship. Research shows that an important risk factor for PSD is the presence of depression in the patient’s family. Most studies of genetic predisposition concerning the occurrence of depression under the influence of stress factors concern genes of the serotonin system, mainly the serotonin transporter gene. These studies were also carried out in relation to PSD (Ayerbe et al., Reference Ayerbe, Ayis, Wolfe and Rudd2013; Kim et al., Reference Kim, Stewart, Kang, Bae, Shin and Kim2014; Kohen et al., Reference Kohen2008; Tenev et al., Reference Tenev, Robinson and Jorge2009). Having certain psychological characteristics can also predispose people to depression after their illness. Research shows that selective attention focused on negative traits may significantly affect the occurrence of emotional disorders (Rodin and Littlefield, Reference Rodin and Littlefield1991). That is why it is so important to conduct research in this area and to publish them. As scientists and medical staff, we still have many aspects to explore and establish on this topic. Understanding the nature of the relationship with depression before and after stroke should therefore help tailor better treatments. In terms of its etiology, stroke is characterized by high heterogeneity. This applies to both major types of stroke, i.e. ischemic and hemorrhagic (intracerebral and subarachnoid). The correct determination of the etiology of stroke is of key importance for the method of treatment, prevention, and in the case of suspected genetically determined diseases – also for the planning of genetic tests.