Psychiatry

Alzheimer's Disease & Dementia
Dementia is a clinical syndrome characterized by impairment of multiple higher cortical functions that include memory, orientation, thinking, comprehension, calculation, capacity for learning, language, judgment,  executive function and visuo-spatial function. It is usually accompanied or preceded by deterioration in emotional control, social behavior or motivation.
Alzheimer's disease is the most common cause of dementia. Sporadic cases usually present after >60 year while familial types are rare and present in <60 year of age (early-onset dementia).
Short-term memory loss is the most common early symptom. Other spheres of cognitive impairment manifest after several years.
Anxiety

Anxiety disorders are disorders wherein the patient experiences uncontrollable fear or anxiety with behavioral disturbances that affects normal functioning.

Generalized anxiety disorder is having excessive anxiety and worry occurring for at least 6 months about several events or activities. The person finds it difficult to control the worry.
Panic disorder is when the person experienced recurrent unexpected panic attacks.
Social anxiety disorder is marked and persistent fear of social or performance situations in which the person is exposed to unfamiliar people or to possible scrutiny by others.

Attention Deficit/Hyperactivity Disorder
Attention Deficit/Hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by the presence of impairing levels of inattention, disorganization &/or hyperactivity-impulsivity.
Symptoms that suggest ADHD includes hyperactivity, acting without thinking, inattention/daydreaming, fidgety, restless, excessive talking, aggressive behavior, academic underachievement, disorganized and has difficulty in completing task.
Bipolar Disorder
Bipolar I disorder is primarily defined by manic or mixed episodes that last for at least 7 days, or very severe manic symptoms needing immediate hospital care. The patient also has depressive episodes which may last for at least 2 weeks.
Bipolar II disorder is usually misdiagnosed. It is characterized by occurence of ≥1 major depressive episodes with at least 1 hypomanic episode.
Cyclothymic disorder or cyclothymia is a mild form of bipolar disorder. Patients have  episodes of hypomania alternating with mild depression that lasts for 2 years.
Rapid-cycling bipolar disorder patients have ≥4 episodes of major depression, mania, hypomania or mixed symptoms within a year.
Depression

Depression is a mood disorder wherein the patient have a pervasive sad mood or loss of interest in most activities for at least 2 weeks.

It can cause significant distress & impairment. It is also a chronic, episodic and relapsing syndrome.

Treatment can either be by psychotherapy alone or pharmacotherapy alone or psychotherapy combined with pharmacological therapy.

Insomnia

Insomnia can be either having difficulty in initiating sleep, maintaining sleep or experiencing early morning awakening wherein returning to sleep is not easily attained.

These disturbances can cause significant distress and impairment in daytime functioning.

It is the most prevalent sleep disorder in the general population thus accurate diagnosis and effective treatment is necessary.

Obsessive-Compulsive Disorder
Obsessive-compulsive disorder is characterized by the presence of either obsessions or compulsions, but more commonly by both symptoms that can cause marked impairment or distress.
Obsession is a recurrent, persistent, intrusive, unwanted thought, image or urge that cause distressing emotions (eg anxiety and disgust).
Compulsion is a repetitive behavior or mental act that the person feels driven to perform, in order to lessen the distress caused by the obsession.
Anxiety is the central feature of obsessive-compulsive disorder.
Premature Ejaculation
Premature ejaculation is a male sexual dysfunction characterized by short, easily stimulated ejaculation that occurs always or nearly always before or within one minute of vaginal penetration.
It is involuntarily controlled and causes negative personal consequences like distress, frustration and avoidance of sexual intimacy.
Exact etiology and risk factors are unknown.
Premenstrual Dysphoric Disorder
Premenstrual dysphoric disorder is a cyclical disorder presenting with distressing mood and behavioral symptoms that occur during the late luteal phase of the ovulatory cycle; it is a severe form of premenstrual syndrome.
It results in considerable impairment of the patient's personal functioning that occurs in approximately 5% of women of reproductive age.
Schizophrenia
Schizophrenia is a devastating mental illness characterized by symptoms eg hallucinations, disorganized thinking, loss of goal-directed behaviors and deterioration in social role functioning.
Positive or psychotic symptoms are delusions, hallucinations, and distorted perceptions.
Negative symptoms include flat or blunted emotions, lack of motivation or energy, lack of pleasure or interest in things, and limited speech.
Disorganized symptoms are confused thinking, disorganized speech and behavior.
Cognitive symptoms include impairment in attention verbal fluency memory, and executive functioning.
Tourette's Syndrome & Other Tic Disorders
Tics are sudden, rapid, non-rhytmic, repetitive, motor movements or vocalizations. The mean age of onset is approximately 5 years old.
Tourette's syndrome is the most common form of tic disorder.
There is a strong genetic component showing a 10- to 100-fold increase in the rates of tics and Tourette's syndrome among first-degree relatives of Tourette's syndrome patients.
Simple motor tics are restricted to a single or a few muscle groups and last less than a fraction of a second.
Complex motor tics involve larger muscle groups, usually last longer and appear purposeful and goal-directed.