Exercise as it relates to Disease/Does Physical Activity act as a protective barrier against Depression in adolescents?

What is the Background to this Research?
Major depression (MD) is a psychiatric syndrome that is estimated to effect up to 10- 20% of the general population. The symptoms of Major Depression can result in deterioration and impaired functioning in almost all aspects of a persons life . Depression is when an individual has continuous severely depressed moods/feelings, not only do theses moods last for longer periods of time, they also occur regularly. The high frequency of Mental illnesses among adolescents and the potential long term consequences from these Illnesses make the relationship between physical activity and depressive symptoms very important. Physical Activity is already identified to lower other risk factors for other health conditions such as Cardiovascular diseases, diabetes, cancer and obesity, but there is limited research to determine if it acts as a protective barrier to mental illnesses. Symptoms include:
 * Depressed mood
 * Weight gain/loss
 * Insomnia/ Hypersomnia
 * Restlessness/ Lethargy
 * Worthlessness/ Guilt feelings
 * Decreased interested/ pleasure
 * Recurrent thoughts of death/ suicidal thoughts

Treatment There is a variety of different treatments which on all depend on the severity of the patients depression and should be designed specifically to the individuals needs. Some cases only require psychological therapy such as psychotherapy, supportive therapy, cognitive therapy or group therapy. Moderate to severe cases require a combination of psychological and medical treatments, Anti-depressant medication is the most common used to treat Depression.

Physical Activity and depressive symptoms in adolescents: A prospective study
This study examines the relationship between Physical activity and depression using the research from with East London Adolescents: Community Health Survey (RELACHS). The aim is this study is to determine whether exercise/physical activity has any relationship with depression and to answer the question, does physical activity act as a protective barrier for adolescents from depression.

What kind of research was this?
The research was qualitative and was measured with Short Mood and Feelings Questionnaires. The data for this study came from RELACHS, an epidemiological study of adolescents. Participants were recruited from three local Education Authority (LEA) boroughs in East London: Hackney, Newham and Tower Hamlets in 2001. Social demographic measures such as: gender, ethnicity, religion and parental employment were collected from the questionnaire and routinely collected data. After obtaining further funding a follow-up study took place in 2003, where data was collected from the same participants.

What did the research involve?
The research involved conducting surveys on adolescents using specially designed Short mood and feelings questionnaires (SMFQ), linguistic regression analyses were then used to examine the relationship between physical activity and depressive symptoms both cross-sectionally and longitudinally. The SMFQ's included 13 statements regarding emotion and behaviour over the past 2 weeks. The results for the questions we added together to produce an overall magnitude of symptoms with a score of ≥8 indicating the presence of depression. The original validation against the Diagnostic interview Schedule for Children - Depressive Scale this threshold produced a positive predictive value of 80% and a negative predictive value of 68%.

What were the basic results?
Out of the 3,322 students who completed the questionnaires 84% (2,789) were valid responses and a further 2,093 (75%) in 2003 were followed up on. Nearly one quarter of the students showed enough depressive symptoms to be considered depressed. Levels of physical activity varied, with most students undertaking between 0.5 to 2-3 h of physical activity a week. There was moderate evidence for a cross-sectional association between physical activity and depressive symptoms for both girls and boys at baseline, with a decrease in the odds of depressive symptoms of 8% for each additional hour of exercise undertaken per week. Unfortunately there was no statistically significant association between physical activity and depressive symptoms in a longitudinal analysis.

How did the researchers interpret the results?
After conducting this study the researchers determined that there is a relationship between the number of hours of physical activity completed and depressive symptoms in adolescents. Furthermore, with each hour of physical activity completed there is an 8% decrease in the odds of an adolescents to have any depressive symptoms.

What conclusions should be taken away from this research?
This study suggests that there is an association between physical activity and lower risk factors of depression for adolescents although the results are tentative. Unfortunately before exercise can widely known as a protective barrier to teenagers or a specific recommended as a treatment/ prevention for this mental health illness more research is required, in particular longitudinally.

What are the implications of this research?

 * This study suggests that there is an association between physical activity and mental well-being in adolescents.
 * Further research is required into the methods/mechanisms of associating physical activity and depressive symptoms. The results suggest that the link cannot be explained by differences in socioeconomic within in this population.
 * Although there is a considerable amount of research conducted on adults with depression, there is limited on adolescents.