Depression is the common cold of mental disorders; most people will be affected by depression in their lives either directly or indirectly, through a friend or a family member. Depression is characterized by a number of common symptoms. These symptoms include a persistent sad, anxiety and feelings of guilt, worthlessness and hopelessness. They no longer take interest or pleasure in hobbies and activities they were once enjoyed [1].

This study focuses upon the prevalence of clinical depression among adolescent females. Adolescent girls are more than twice as likely to be diagnosed with mood disorders as boys, because they mature in term of emotional recognition faster than boys, and that sensitivity could make them more vulnerable to depression and anxiety [2]. There are two major diagnostic methods typically used to diagnose depression: the diagnostic and statistical manual of mental disorders DSM developed by the American psychiatric association and the method developed by the World Health Organization WHO in 1990.

The American psychiatry association method is the one mostly used in the United States and worldwide [3]. The aim of this study is to use an easy and efficient way to detect cases of clinical depression, like anonymous questionnaires. The use of anonymous questionnaire shows a higher rate of response among students because they find it impersonal and confidential [4].

In this study we used the patient health questionnaire PHQ-9 created by Drs Spitzers Williams and Kroenke with the support of an educational grant from Pfizer Inc. In this study the respondents were informed of the nature and aims of the study and the types of questions. In addition, the questionnaire was anonymous and the information gathered was used only for the purpose of this study. PHQ-9 depressive severity score is calculated by assigning scores of 0, 1, 2, 3 to the response category ‘not at all’, ‘several days’, ‘ more than have of the days’ and ‘ nearly every day’ respectively.

PHQ-9 total score for nine items ranges from 0 to 27, where total scores 0-4, 5-9, 10-14, 15-19 means none, mild, moderate, moderately severe, severe respectively. The questionnaire used in this study was in Arabic language and downloaded directly in Arabic form the Pfizer website [5].

The results in this section are classified only by the final score result of the questionnaire regardless of the different ages, as the aim of this study is to calculate the overall prevalence of depression among the respondents. Out of the total 262 females who participated in the study the final results based upon scoring of the PHQ-9 questionnaire came out as the following (Tables 1a and 1b):

Table 1a: Illustrates the frequency of different ages based on public health questionnaire (PHQ-9).

Table 1b: Illustrates the frequency of different ages.

• 45.4% Score 0-4 = None.

• 31.7% Score 5-9 = Mild.

• 13.7% Score 10-14 = Moderate.

• 7.6% Score 15-19 = Moderately severe.

• 1.5% Score 20-27 = Severe.

This study measured the overall prevalence of clinical depression among Libyan females; the respondents sampled in this study were fully oriented with questions and answers found in the questionnaire. Furthermore, the results of the study showed a high prevalence as 7.6% and 1.5% of the respondents diagnosed with severely moderate and severe depression respectively. These results were compared to previous similar studies and found nearly similar results.

Overall 8.8% of respondents reported diagnosed with anxiety and 4.3% with depression, and more female students reported anxiety and depression than male student [6].

The mental health services in Libya were woefully inadequate before and after the civil war following the Arab spring 0f 2011, the mental healthcare that does exist in Libya is mainly in the form of highly centralised institutional in-patient services [7]. Therefore, more focus on detecting cases of clinical depression in primary health centres, schools and other institutions by using easy methods like questionnaires, especially in Libya.

This study has some limitations, one of the limitations is the small number of the sample used that may not adequately represent the entire Libyan female population, another limitation is that this study looked at the total prevalence of depression in the sampled respondents regardless of their socioeconomic class or family history of mental disorders.

Depression is a real clinical disorder of a high prevalence in our society as shown by the numbers of this study, therefore more specific measures should be taken in order to detect cases of clinical depression and provide them with the appropriate counselling as this was the aim of this study.

For their advice and assistance throughout this study I would like to express my sincere gratitude and appreciation to the following:

• Dr. Hajer Elkout, a teaching staff member at the University of Tripoli, Faculty of Medicine Department of Family Medicine.

• Dr. Taha Mahmoud Gharghni, MBBCH, University of Tripoli, Faculty of Medicine.

• The Administrations of the (24^th December) School and the High Centre of Comprehensive Professions.